Owner: Chief Engineer Civil Approved by: John Stapleton A/Principal Engineer Technology & Standards Authorised by: Richard Hitch Chief Engineer Civil Disclaimer This document was prepared for use on the RailCorp Network only. RailCorp makes no warranties, express or implied, that compliance with the contents of this document shall be sufficient to ensure safe systems or work or operation. It is the document user’s sole responsibility to ensure that the copy of the document it is viewing is the current version of the document as in use by RailCorp. RailCorp accepts no liability whatsoever in relation to the use of this document by any party, and RailCorp excludes any liability which arises in any manner by the use of this document. Copyright The information in this document is protected by Copyright and no part of this document may be reproduced, altered, stored or transmitted by any person without the prior consent of RailCorp Page 1 of 72 UNCONTROLLED WHEN PRINTED Engineering Manual Structures TMC 300 STRUCTURES GENERAL Version 2.2 Issued July 2010 Engineering Manual
Transcript
Owner: Chief Engineer Civil
Approved by: John Stapleton A/Principal Engineer Technology & Standards
Authorised by: Richard Hitch Chief Engineer Civil
Disclaimer This document was prepared for use on the RailCorp Network only. RailCorp makes no warranties, express or implied, that compliance with the contents of this document shall be sufficient to ensure safe systems or work or operation. It is the document user’s sole responsibility to ensure that the copy of the document it is viewing is the current version of the document as in use by RailCorp. RailCorp accepts no liability whatsoever in relation to the use of this document by any party, and RailCorp excludes any liability which arises in any manner by the use of this document. Copyright The information in this document is protected by Copyright and no part of this document may be reproduced, altered, stored or transmitted by any person without the prior consent of RailCorp
Page 1 of 72 UNCONTROLLED WHEN PRINTED
Engineering Manual Structures
TMC 300
STRUCTURES GENERAL
Version 2.2
Issued July 2010
Engi
neer
ing
Man
ual
RailCorp Engineering Manual — Structures Structures General TMC 300
Document control Revision Date of Approval Summary of change
2.2 Changes detailed in chapter revisions below
2.1 May 2009 Format change throughout; C8-1 Transoms deleted & incorporated in TMC 311; Appendix 3 deleted; Appendices 4 to 7 renumbered
2.0 October 2007 Updated References; added definition of “site supervisor”; addition of management requirements; added competencies; Updated and new requirements based on changes to structures standards; C4-7.2: tensioning of bolts; New C4-10: track baulks; C4-12: additional details from Construction Specification S20 re nameplates; C5-1: lift structures; C5-2: additional parameters for risk assessment; C6-1: types of trackside structures; C11-6: additional requirement re water not dripping onto tracks; C11-9: CTN 07/04 re name signs; Inclusion of definitions for ballast kerb & ballast retention wall; Details of Withdrawn Standard Plans; New: CTN 00/01 Transom Bolts; New Standard OHWS Drawings
1.0 December, 2006 First issue as a RailCorp document
Summary of changes from previous version Chapter Current Revision Summary of change
Control Pages
2.2 Updated version details
4 2.2 New C4-9.1 General; C4-9.2 clarification of approval requirements
C7-3.3 2.2 Add guard rail insulation requirements from CTN 08/06
RailCorp Engineering Manual — Structures Structures General TMC 300
Chapter 3 Competencies............................................................................................................................ 9 Chapter 4 General Requirements for Bridges and Structures............................................................. 10
Chapter 13 Miscellaneous Structures ...................................................................................................... 43 C13-1 Overhead Service Crossings .................................................................................................... 43 C13-2 Noise Barrier Walls ................................................................................................................... 43 C13-3 Rockfall Shelters ....................................................................................................................... 43 C13-4 Lighting and Communications Towers...................................................................................... 43 C13-5 Structures Over & Adjacent to Tunnels .................................................................................... 43
Chapter 14 Air Space Developments........................................................................................................ 45 C14-1 Existing Developments ............................................................................................................. 45 C14-2 Refurbishment of Existing Developments................................................................................. 45 C14-3 Design Requirements ............................................................................................................... 45 C14-4 Construction Requirements ...................................................................................................... 48 C14-5 Information to be Supplied at the Design Stage ....................................................................... 49 C14-6 Documentation to be Submitted Prior to Construction ............................................................. 50
Chapter 15 External Developments .......................................................................................................... 51 C15-1 General Requirements.............................................................................................................. 51
Appendix 1 Terms Used in Bridges and Structures ................................................................................ 52 Appendix 2 Withdrawn Standard Plans .................................................................................................... 58
RailCorp Engineering Manual — Structures Structures General TMC 300
This Manual outlines miscellaneous requirements for installing and maintaining structures. It includes relevant information from the Structures Design Standards.
The Manual covers:
− General requirements such as structural bolts, excavation works, and the operation of the ballast stabilising machine near structures
− Collision protection of existing structures
− Safety refuges, handhold devices and limited clearance signs
− Guard rails
− Structures including underbridges, overbridges, footbridges, overhead wiring structures, signal gantries, tunnels, retaining walls, platforms miscellaneous structures, air space developments and external developments
− Typical structures configurations.
The Manual is intended for use by staff and contractors undertaking construction and maintenance work on structures or in the vicinity of structures.
The Manual is primarily intended for use by structures staff and contractors but includes some requirements for personnel involved in track work and platform upgrading work.
C1-2 References C1-2.1 Australian & International Standards
NSW Rail Safety Act 2002
NSW Heritage Act 1977 and Heritage Regulation 1999
AS 1252-1996 “High strength steel bolts for structural engineering”
AS 1449-1994 “Wrought alloy-steels – Stainless and heat-resisting steel plate, sheet and strip”
AS 1657-1992 “Fixed platforms, walkways, stairways and ladders – Design, construction and installation”
AS 1720.1-1997 “Timber Structure – Design methods”
AS 3600 -2001 “Concrete structures”
AS 4100 -1998 “Steel structures”
AS 4292-2006 “Railway safety management”
AS 4678 -2002 “Earth-retaining structures”
AS 5100-2004 “Bridge design”
C1-2.2 RailCorp Documents EP 08 00 00 07 SP - Safety Screens for Bridges over 1500 V OHW Equipment
ESC 215 - Transit Space
ESC 380 - External Developments
SPC 301 - Structures Construction
RailCorp Engineering Manual — Structures Structures General TMC 300
C1-2.3 Other RTA Technical Direction TD 2002/RS02 “Policy for Safety Screening of Bridges”
RTA-2000 “Bridge Waterway Manual”
Austroads-1994 “ Waterway Design”
C1-3 Definitions, abbreviations and acronyms Site Supervisor: A qualified civil engineer or a competent person with delegated
engineering authority for civil construction supervision. Terms used in the design, construction and maintenance of RailCorp’s bridges and structures are provided in Appendix 1 of this Manual.
RailCorp Engineering Manual — Structures Structures General TMC 300
− Compliance with the requirements for bridges and structures detailed in this Manual.
− Installation, inspection and maintenance tasks are undertaken by people who have the required competencies.
C2-2 Renewals Manager/Project Manager Establish systems to ensure:
− Construction and installation tasks are undertaken by people who have the required competencies.
− Approved designs are used for the replacement and refurbishment of bridges and structures.
C2-3 Team Manager/Site Supervisor Ensure that construction, installation and maintenance tasks are undertaken by people who have the appropriate competencies.
RailCorp Engineering Manual — Structures Structures General TMC 300
Chapter 3 Competencies The construction and installation of bridges and structures shall be carried out by persons with the appropriate civil construction competencies and under the supervision of a Site Supervisor.
The inspection of bridges and structures shall be carried out by persons with:
Chapter 4 General Requirements for Bridges and Structures C4-1 General
Bridges shall be managed in accordance with the Railway Bridge Policy.
Bridges and structures within the RailCorp network are to be designed, installed and maintained in a condition appropriate to the traffic task and safe operations, at the lowest overall life-cycle and operational cost.
Bridges and structures will be generally designed for a design life of 100 years, in accordance with AS 5100 “Bridge design”. Major assets in service such as steel truss bridges, long viaducts and tunnels will however be maintained and preserved for an indefinite service life.
Work is to be done in accordance with relevant RailCorp Engineering Manuals. Work is to be done by persons with appropriate technical competencies and engineering authority as detailed in TMC 001 “Civil Technical Competencies and Engineering Authority”.
C4-2 Heritage All construction and maintenance personnel are required to be aware of any heritage restrictions or requirements before undertaking maintenance work on an existing structure, where the configuration or components are being materially altered.
A Certificate of Heritage Status is to be obtained before major alterations are carried out or before a redundant structure is demolished.
C4-3 Clearances Horizontal and vertical clearances for bridges, structures and services attached to bridges and structures are to comply with RailCorp’s Engineering Standard ESC 215 “Transit Space”.
The area extending one metre below design rail level of Normal Structure Gauge 1994 as detailed in ESC 215 Figure 1 shall be kept clear of structures and structure footings.
The design of trackside structures shall also provide clearances for safe places as detailed in Chapter 6 of this manual.
Clearances from the track to piling equipment when constructing substructures shall take account of transit space, safeworking and construction requirements. The minimum clearance is the kinematic envelope (out-of-gauge load) plus 200 mm.
C4-4 Approved Materials Approved construction materials for main structural elements are steel and concrete.
Apart from transoms, timber materials shall not be used as structural elements in the design of structures.
Masonry is approved for existing structures and for cladding of new structures where this is required in special circumstances such as for heritage reasons.
Materials and finishes should be chosen to minimise future maintenance due to the close proximity of the structure to the tracks and commuter usage. Stainless steel fasteners are to be specified where access for inspection and replacement purposes is difficult.
In locations that are vulnerable to vandalism and graffiti, appropriate measures are to be taken to prevent access to the adjoining rail infrastructure. Anti-graffiti paints should be specified in areas where there is a high risk of graffiti.
Trackside structures shall not be painted in safeworking colours of red, orange and green.
RailCorp Engineering Manual — Structures Structures General TMC 300
C4-5 Standard Plans Over the years Standard Plans have been developed for many rail assets. Many of the plans have been superseded with the development of new standards.
Books of Standard Plans are still in existence in some offices. The Standard Plans are available in the Plan Room. Whilst this is necessary for the maintenance of old assets originally built to the plans, the plans are generally not suitable for use in the design of new assets.
The Standard Plans listed in Appendix 2 are withdrawn from use for design of new assets and refurbishment/upgrading of existing assets. Plans may be used on particular projects if approval is obtained from the Chief Engineer Bridges and Structures.
C4-6 Services Services and service ducts shall be located so as not to impede access to the structure and to the services for inspection and maintenance.
No services are to be placed under bridges or through culverts without the approval of the Chief Engineer Civil.
No services are to be attached to bridges and structures without the approval of the Chief Engineer Civil. Proposals are to include a risk assessment of the impact on the structure and other RailCorp assets in the area.
No services are to be carried in an open channel system.
Where service ducts are attached to a bridge walkway, they must be positioned so that they do not encroach on the safe working area or create a trip or other safety hazard.
When approval is given to place a pipe under a bridge the trench shall be excavated no closer than 3m to the footings of any abutment or pier. The excavation shall not undermine the bridge footing or lead to instability due to sliding of the abutment or pier. The stability of the abutment or pier shall be checked for the temporary open trench condition and it shall be demonstrated that the requirements of AS 5100 have been met.
When approval is given to install a pipe through a concrete culvert, the pipe shall be located close to the culvert wall and as close to the soffit as possible. The pipe is to be located by grouting under and over the pipe to present a smooth surface to the water passing through the culvert. The pipe is to return underground at each end of the culvert as quickly as practical.
C4-7 Structural Bolts and Anchors C4-7.1 Structural Bolts
Most of RailCorp’s connections for bridges and structures comprise bolts, designated 4.6 or 8.8, of snug tight, friction or bearing type or huck bolts, in accordance with AS1252-1996 “High strength steel bolts for structural engineering”.
Structural connections are generally the weakest elements of a bridge or structure. To reduce the risk of structural failure due to inadequate connection capacity, the following policies are to be followed by construction and maintenance personnel:
− The preference is to use huck bolts;
− High strength bolts (8.8TF or TB) can be used provided a certificate of compliance is available from an Agency acceptable to the Chief Engineer Civil for the batch of bolts;
− If a certificate of compliance (for the bolt and particular batch) is not available, one of the following options shall apply:
∼ Bolts of the same batch shall be tested in accordance with AS1252-1996 by a NATA registered laboratory. It shall be permissible to demonstrate compliance with AS1252-1996 up to one month after installing the bolts;
∼ With prior engineering design approval, it shall be permissible to increase the bolt size
RailCorp Engineering Manual — Structures Structures General TMC 300
Upon completion of the works, the Structures Manager or equivalent shall appropriately file all certificates of compliance.
C4-7.2 Tensioning of Bolts Structural bolts are to be tensioned in accordance with the requirements of SPC 301 “Structures Construction” S26 “Erection of Structural Steel”.
Direct-tension indication devices may be used provided they conform to the requirements of AS 4100 “Steel structures” - Clause 15.2 and they are used strictly in accordance with the manufacturers’ instructions.
C4-7.3 Anchors Both mechanical and chemical anchors are commonly used to attach minor structures such as OHW masts and traffic barrier posts to bridges and other major structures.
A number of proprietary products such as ‘Chemset’ and ‘Dynabolt’ anchors are available for a range of applications. The load carrying capacity of these products is normally based on concrete strength. The manufacturers however do not accept any liability for their anchors if they are not installed properly in the right type of material in accordance with the manufacturer’s written instructions.
There have been many cases of failures of anchors installed in aged structures or in unsatisfactory materials, e.g. aged concrete or fragmented brickwork. As such if there is any doubt as to the quality of the material into which the anchors are to be installed or type of anchor to be used, reference should be made to the Chief Engineer, Civil Section.
C4-8 Buried Metal Structures Buried metal structures (e.g. corrugated metal pipes) are generally not suitable for use in electrified areas and are not to be used for drainage or structure repairs/ replacements.
C4-9 Excavation Works C4-9.1 General
Excavation works for structures are to be planned and managed in accordance with SMS-06-GD-0378 System Guide Excavation and Earthworks.
C4-9.2 Structure Footings When excavating adjacent to structures, there is a risk that the footings may be undermined or the structure destabilized, resulting in structural failure and potential collapse.
Excavations in the vicinity of structure footings are therefore not permitted unless documented engineering advice and approval are obtained.
No excavation should be made within this 5m distance without prior analysis of structure stability with respect to the effects of the excavation.
No excavation shall be made below the base of the footings of any structure (for example bridges, retaining walls and station platform walls) without prior analysis of structure stability with respect to the effects of the excavation.
The approval will be in the form of a certification by a competent geotechnical/ structural engineer with relevant engineering authority, based on the results of an appropriate geotechnical and/or structural investigation.
This requirement extends to the footings of all structures such as bridge piers, abutments, wingwalls, tunnels, retaining walls, platform walls, overhead wiring structures, signal gantries and towers.
RailCorp Engineering Manual — Structures Structures General TMC 300
C4-10 Track Baulks Standard design details have been developed for track baulks for concrete sleepered track. The designs cover openings less than or equal to 2.5 metres, and openings 3 metres to 6 metres.
The standard drawings are:
CV 0352342 Standard - Track Baulks for Concrete Sleepers < 2.5m Opening, General Arrangement
CV 0352343 Standard - Track Baulks for Concrete Sleepers < 2.5m Opening, Steelwork Details
CV 0352344 Standard - Track Baulks for Concrete Sleepers 3m - 6m Openings, General Arrangement
CV 0352345 Standard - Track Baulks for Concrete Sleepers 3m - 6m Openings, Steelwork Details Sheet 1 of 3
CV 0352346 Standard - Track Baulks for Concrete Sleepers 3m - 6m Openings, Steelwork Details Sheet 2 of 3
CV 0352347 Standard - Track Baulks for Concrete Sleepers 3m - 6m Openings, Steelwork Details Sheet 3 of 3
C4-11 Electrical Requirements C4-11.1 Earthing and Bonding
Earthing and bonding of metallic components on structures is required so as to mitigate touch potential hazards and corrosion of steel.
Requirements for earthing and bonding of metallic components on bridges and structures are:
− Steel and concrete bridges shall be insulated from earth.
− Overhead wiring structures on bridges and platforms shall be bonded via a spark gap.
− Overhead wiring fittings attached to a bridge shall have tertiary insulation and be bonded via a spark gap.
− Vertical safety screens shall be insulated from the bridge structure.
− Horizontal safety screens shall be insulated from the bridge structure and shall be bonded via a spark gap.
− Other metallic components such as walkways, refuges and handrails shall be insulated from the structure.
− Utility services, such as water, gas, communications and lights, shall be insulated from the structure. There shall be a 2 metre separation between light columns and any other metallic structure.
Insulation panels may be required in fences and vertical safety screens to prevent transfer of potential.
Electrical requirements are specified in RailCorp Electrical Engineering Standards for Earthing, Bonding and Electrolysis. If in doubt, advice should be sought from the Electrical Maintenance Engineer for the area.
C4-11.2 Clearances to Electrical Services and Equipment Electrical services within the rail corridor include aerial lines, 1500V dc overhead traction wiring and equipment and exposed low voltage equipment.
Bridges and structures are to be designed and constructed to ensure that minimum clearances are observed to electrical power lines and equipment, as laid down within the Australian Standards, the regulations of the relevant electrical authorities and RailCorp’s Electrical Engineering Standards.
Where high voltage aerial lines are located above the bridge, measures shall be taken to ensure that the risk of transferred potential associated with fallen conductors is mitigated.
RailCorp Engineering Manual — Structures Structures General TMC 300
The deck structure in the vicinity of overhead wiring beneath the bridge shall be designed to provide an impenetrable barrier intended to prevent persons from contacting 1500V dc equipment.
C4-12 Nameplates and Plaques New underbridges and underbridges that undergo major refurbishment are to be provided with nameplates, indicating the kilometrage and year of construction. The nameplates will normally be of brass construction and fitted to the outside of the bridge kerb at the Sydney end.
For ballast top bridges, plaques or stencilling are also to be installed in a visible location on the top of the kerbs, providing a warning that excess ballast and lifting of the track above the design level are not permitted over the bridge.
New overbridges and footbridges and bridges that undergo major refurbishment are to be provided with nameplates, indicating the Constructing Authority (e.g. RailCorp) and year of construction. The nameplates will normally be of brass construction and fitted to a suitable location on the Down side of the bridge (e.g. bridge kerb or balustrading end-post).
The name plate shall comprise of a 200 mm X 350 mm brass plate with the required information engraved on a raised surface. Each letter or number of the text on the first or second line shall be 20 mm high and suitably wide.
The raised portion and the edges of the name plate shall be polished.
The name plate shall be fixed on at approximately 500 mm from the edges of the external steel main girder’s webs at Sydney abutment end.
The fixing shall be by 4 off 10 mm diameter countersunk brass screws.
C4-13 Advertising Signs Fixing details shall be in accordance with design codes and practices. They shall not impact on the structural integrity of the bridge. They shall only be made into existing structural members with the approval of the Chief Engineer, Civil. They shall not create an obstruction that causes water to pond or debris to accumulate on the bridge structure.
Fixings and ladders for the sign shall not impinge on the clear walking space of footbridges and pedestrian walkways.
Signs and fixings shall not prevent access for inspection and maintenance of the bridge, including the structure immediately behind the sign.
Vibrating forces generated by dynamic ballast stabilizing machines can be quite powerful and under certain conditions may excite critical vibration frequencies in nearby structures. Fortunately, most structures have critical frequencies in the low portion of the stabiliser's vibration range. For these reasons, the stabiliser must not be operated at frequencies below 40Hz over ballast top underbridges.
When starting the vibration units they MUST be engaged onto the rails and brought up to the required vibrating frequency as fast as possible. Conversely when stopping the vibration units they MUST be stopped as fast as possible. This will prevent any possible critical vibration frequency ranges from being prolonged. Starting and stopping the vibration units MUST occur only when the machine is moving.
The dynamic stabilising machine must finish its run-out ramp, i.e. at zero pressure and vibrators turned off whilst moving, no closer than 10 metres to the nearest extremity of a bridge abutment or return wingwall. The reverse is to apply at the start of the operation, i.e. when moving away from the structure.
RailCorp Engineering Manual — Structures Structures General TMC 300
− Brick or masonry underbridge spans over 5 m long where the parapets directly contain the ballast (concrete bridges are OK);
− A masonry or any other type of culvert less than 5 metres span and only if the culvert has a minimum of 1 metre fill between the top of the culvert and the underside of the ballast bed and only if free of structural defects.
− A modern pre-stressed concrete reinforced concrete or steel underbridge, only with concrete piers and abutments and only where these substructure elements have been constructed/renewed at the time of the deck construction.
In order to avoid possible damage to structures or the machine itself, the stabiliser must NOT be used in the following circumstances:
− On any track with heavily fouled or cemented ballast;
− On transom top or open top bridges;
− On ballast top timber bridges;
− On ballast top steel trough bridges;
− In tunnels;
− On track which is within 5m of multi-storey buildings;
− On concrete slab track;
− Over pits;
− Over any level crossing that has not been recently tamped;
− At locations near old or fragile signalling equipment as specified by a Signalling Engineer;
− Through turnouts, crossovers and diamonds and similar locations where the track has not been recently tamped and then only with care and with the roll clamps open;
− Through platforms where the ballast between sleeper ends and the platform wall is heavily fouled.
The above operating procedures and restrictions assumes that bridge components are free of structural defects. If this is not the case, reference should be made to the Civil Maintenance Engineer for further direction.
RailCorp Engineering Manual — Structures Structures General TMC 300
Chapter 5 Collision Protection of Existing Structures C5-1 General
Supporting structures (including bridges, airspace developments, lift structures) within the rail corridor require some form of protection against damage from a derailed vehicle, which in turn could result in collapse of the structure onto the train. This requirement is now taken into consideration during the design of all new structures, in accordance with the provisions of collision protection and loading in AS 5100.
C5-2 Assessment of Damage Potential Existing supporting structures (including temporary structures) may not be adequately protected from a derailed vehicle. The Civil Maintenance Engineer is responsible for the assessment of potential damage and the implementation of appropriate protection to these structures where warranted, in accordance with the guidelines below.
In general, only those structures carrying vehicular or pedestrian traffic over the track are to be included in the assessment.
The risk assessment is to be performed in accordance with RailCorp’s Safety Risk Management System and should take into account the following parameters:
− Site condition, cutting, embankment etc.
− Derailment history
− Type of structure, i.e. potential for collapse damage to trains
− Track geometry
− Track speed
− Type of rolling stock
− Future usage and growth in patronage.
The risk analysis shall also consider any other relevant site specific criteria.
Following the risk assessment, the Civil Maintenance Engineer is to prepare a list of structures requiring additional protection in priority order. He should also advise supervising officers of the priorities and costs, for inclusion in resource allocations
For those structures determined by the risk assessment as requiring additional protection, an appropriate device should be installed. The preference is to use deflection walls, however lower order protection devices such as earth mounds, gabions or guard rails etc. may be used if approval is obtained from the Chief Engineer Civil.
Specific locations may be referred to the Chief Engineer Civil for guidance and design input.
C5-3 Deflection Walls Deflection walls shall comply with the structural configuration and geometric requirements of AS 5100.1. In addition, they shall have the leading faces rounded or vee-shaped.
In the case of retrofitting a deflection wall to an existing vulnerable pier or column, as well as infill walls, end walls shall extend parallel to the track, 3 metres on the approach side of the pier or column.
C5-4 Guard Rails Where guard rails are determined to be the most appropriate device for providing protection at a specific location, they are to be installed in accordance with RailCorp’s standard design and configuration (refer to Chapter 7).
RailCorp Engineering Manual — Structures Structures General TMC 300
Chapter 6 Safety Refuges C6-1 Provision of Safe Areas
Provision is to be made for a ‘safe area’ adjacent to trackside structures for infrastructure and other authorised staff to stand during the passage of a train.
The principles adopted for the determination of clearance requirements are as follows:
− a ‘safe area’ will be a place where no part of a person or piece of equipment encroaches closer to the track than the kinematic envelope (out-of-gauge load) plus a safety margin of 200mm;
− the minimum depth for a safe standing area is 400mm;
− the kinematic envelope is the widest swept path of the rollingstock. Where out-of-gauge loads normally operate or are capable of operating, this outline is to be used;
− the basic premise is that a location is deemed to be safe unless otherwise indicated.
A ‘safe area’ must be provided along wall structures where the wall is longer than 20 metres.
In lieu of calculating kinematic envelopes, the default clearances to the front of the ‘safe area’ are:
− 2230mm on tangent track
− 2500mm on curved track.
C6-2 Locations with Limited Clearances C6-2.1 Clearance less than kinematic plus 600mm:
When the clearance dimension from the track centreline to the structure is less than kinematic plus 600mm, refuges are to be provided for wall structures longer than 20 metres.
C6-2.2 Clearance between kinematic + 600mm and kinematic + 1200mm When the clearance dimension from the track centreline to the wall structure is between kinematic plus 600mm and kinematic plus 1200mm, handhold devices as specified in C6-6 are to be provided for wall structures longer than 20 metres.
C6-2.3 Limited Clearance Sign Owing to physical constraints, it may not always be possible to provide refuges or handhold devices along new or existing wall structures.
Where refuges or handhold devices are required but are not provided, wall structures shall have warning signage attached. The sign is shown in C6-7.
Warning signs should be considered for wall structures less than 20metres in length where clearance is less than kinematic plus 1200mm.
The sign is a warning that there is insufficient clearance to stand safely when trains are passing.
C6-3 Locations with Adequate Clearances When the clearance dimension from the track centreline to the wall structure is greater than kinematic + 1200mm, no physical protection or signage is required.
C6-4 Location of Refuges, Handhold Devices and Limited Clearance Signs The spacing of safe areas/ refuges/ handhold devices along a wall structure is not to exceed 20 metres. The spacing at each location is to be determined by a risk assessment, taking account of factors such as train speed, available sighting distances, existence of warning light systems.
RailCorp Engineering Manual — Structures Structures General TMC 300
Refuges/ handhold devices shall be provided on one side only of a single track where there are structures closer than the clearances for safe places on both sides of the track.
Where clearances are restricted on only one side of a single track, refuges/ handhold devices are not required. Limited clearance signage is required on the side of the obstruction.
Where refuges/ handhold devices are required on multiple tracks, they shall be provided in a staggered pattern on both sides of the track group.
The limited clearance sign is attached to the wall structure so as to be clearly visible to personnel standing on or adjacent to the track. The sign is required at access points to the limited clearance area.
The sign is to be attached at each end of the wall structure e.g. ends of retaining walls, tunnel portals, entrance to cuttings etc, and at locations along the structure wall where access is available to the track adjacent to the structure.
If access is only available from the end of the structure, no signs are required along the wall.
If access is continuously available, for instance the structure is on one side only, signs are to be installed at maximum 20 metre intervals along the structure.
C6-5 Refuge Details The floor of the refuge is to be at cess level or with a maximum step up above the cess level of 200 mm.
The minimum dimensions of refuges are to be:-
Height: 2000 mm
Width: 1500 mm
Depth: 700 mm If the refuge is to contain telephones, fire extinguishers or other essential items, the width is to be increased to provide the same clear floor area.
The floor of the refuge is to be level. The refuge is to be kept clear of cables, pipes or other obstructions.
Handrails must be installed in all refuges to assist staff in keeping their balance during the passage of a train.
C6-6 Handhold Device Details A schematic layout for a handhold device is shown below.
It comprises two vertical pipe handrails 40 mm diameter, located 1000 mm apart and each protruding 400 mm from the fixing point on the structure.
The pipes are to be manufactured from galvanised steel.
Each handrail extends vertically from 900 mm above cess level to 1800 mm above cess level.
RailCorp Engineering Manual — Structures Structures General TMC 300
The prime purpose of guard rails on underbridges is to keep derailed or derailing bogies/wheels tracked parallel to and in close proximity to the running rails. This action prevents a derailed train from falling over the side of the bridge.
In the case of through girder and through truss type underbridges, the guard rails prevent impact with key structural supporting elements.
For through girder, through truss and direct fix bridges concrete upstands may be provided in lieu of guard rails. The upstands shall be designed for a 80 kN lateral load. The design shall take account of cross drainage requirements. The upstand shall comply with the relevant configuration requirements for guard rails.
In addition, the guard rails, by way of a baulking effect, provide additional support to the track at the bridge ends.
C7-2 General Requirements Guard rails shall be installed on the following underbridges:
− Through span bridges and their approach spans;
− Transom top bridges;
− Ballast top and direct fix bridges over twenty metres in length.
For other ballast top bridges, a risk assessment should be undertaken in accordance with RailCorp’s Safety Management System, to determine whether guard rails are required. The following criteria are to be taken into account:
− Height of bridge;
− Bridge span;
− Bridge configuration e.g through girder, through truss where vulnerable to train impact loads;
− Abutment configuration;
− Probability and consequence of a derailment;
− Track alignment and configuration;
− Train speed, density and type of traffic.
In addition, guard rails may be provided to protect columns on overbridges and air space developments where the columns do not meet the collision protection requirements of AS 5100.
C7-3 Guard Rail Details C7-3.1 Configuration
Guard rail installations are to comply with the following requirements:
− Guard rail shall be new rail or recycled rail Category 1 (White rail).
− Guard rail section is to be the same as the running rail or one section size less than the running rail.
− Top of guard rail is to be no higher than the adjacent running rail and no more than 50 mm below the running rail.
− Each guard rail is to be plated and fastened on both sides to every transom/sleeper.
− For underbridges, guard rails are to extend parallel between the abutments
− For air space developments and overbridges, guard rails are to extend parallel for a minimum 20 metres in advance of the vulnerable support on the train approach side.
RailCorp Engineering Manual — Structures Structures General TMC 300
− Guard rails are to extend parallel for a minimum of 3 metres beyond the abutment or vulnerable support on the train departure side.
− Where rail traffic is bi-directional, the guard rail is to extend parallel for 20 metres beyond the vulnerable support on both approach and departure sides of air space developments and overbridges.
− A tapered nose section (“vee”), minimum 3.6 metres long, is to be installed on the train approach side of the guard rail. The design of the vee shall be in accordance with Drawing Number 785-570. The nose of the vee shall be bolted.
− Where traffic is bi-directional, the tapered guard rail section is to be installed at both ends of the guard rail.
− Clearance between gauge face of running rail and adjacent face of guard rail is to be 380mm.
− Block-out holes for guard rail fastenings in concrete sleepers shall be grouted with an approved high strength grout.
For fixing details, dimensional set-out and componentry detail and sizes, standard guard rail drawings are available:
785-568 Bridge guard rails Ballast top bridge Arrangement for concrete sleepered track
785-570 Bridge guard rails Ballast / Transom top bridge Arrangement for timber sleepered track
785-571 Bridge guard rails Timber sleepered track Details of special plating for tapered nose
C7-3.2 Special Installations Where expansion joints exist, specific design details of guard rail installations will be required. Approved track fixings are to be used. The design is to be certified by a competent design engineer.
Where noise and vibration limiting track fixings are used and there is a mismatch in height between the bridge ties and the end treatment ties, the guard rail and vee shall be supported on all ties with approved products such as rubber pads and fastened to all ties with approved track fixings.
C7-3.3 Signalling Interface Suitable isolation arrangements are to be made, where required, in track circuited and electrified areas.
The tapered nose section (“Vee”) is to be insulated with an approved component - refer to Figure 3. Generally one insulated joint is satisfactory. This insulation requirement applies to new installations and where refurbishment of the guard rails is undertaken.
RailCorp Engineering Manual — Structures Structures General TMC 300
Where guard rails exceed 50 metres in length, additional insulation and bonding arrangements may be required. Design drawings are to specify that insulation and bonding arrangements shall be in accordance with the requirements of the Chief Engineer Signals. See RailCorp Engineering Standard ESG 100.17 - Signal Design Principles Track Circuits.
C7-4 Joints in Guard Rails Whilst no joint is permitted in running rails on bridges, guard rails may have minimal joints with at least two bolts on each side.
If standard fishplates are used, six bolts are required.
If modified fishplates are used, the four bolts shall all have the nuts on the inside. Fishplates shall be modified by machining, not by oxy-acetylene cutting.
No joints are permitted in the vee.
Issued July 2010 UNCONTROLLED WHEN PRINTED Version 2.2
RailCorp Engineering Manual — Structures Structures General TMC 300
− protect authorised personnel from falling when crossing a bridge;
− provide a safe pathway for train crew in the event of a train having stopped or failed on a bridge;
− facilitate track inspection;
− facilitate the replacement of transoms, sleepers and other track components.
Refuges serve the following purpose:
− provide a safe area on a bridge for authorised personnel to stand clear of a passing train.
Note: Standard width walkways do not provide a safe area or refuge.
Handrails serve the following purpose:
− protect authorised personnel and train crew from falling off the side of the bridge and approaches.
C8-2 Walkways C8-2.1 General
Walkways shall be installed on underbridges where the height from bridge deck to the lowest invert level is greater than 2 metres.
Many existing underbridges fail to meet the above requirements. For these structures, undertake a risk assessment and implement a programme of retrofitting of walkways, refuges and handrails in accordance with relative priorities.
When designing the location of walkways on underbridges, consideration is to be given to particular site characteristics such as flood issues (e.g. afflux and debris), track curvature, sighting distances and train lengths.
On single tracks where walkways are required, they should be installed in the following order of preference:
− downstream side of a bridge over water where flood levels are high;
− on the ‘outside’ of a bridge on a curve;
− on the same side of the track on adjacent bridges spaced less than one train length apart, with the ‘worst’ safety access bridge governing the side.
One walkway is to be provided on single track bridges and on double track bridges less than 15 m long. Two or more walkways are required on double track bridges longer than 15 m and on multiple track bridges. Refer to the typical configurations for walkways, refuges and handrails as shown in Appendix 3.
Where provided, walkways are to be extended with suitable detailing at each end of the bridge to provide a safe transition to the approaches and adjoining rail embankments. Particular attention is to be given to the detail where the last walkway panel abuts the face of the abutment, to ensure that adequate support is provided to the walking surface.
C8-2.1.1 Design Criteria The following design criteria shall apply to walkways on underbridges:
RailCorp Engineering Manual — Structures Structures General TMC 300
− normal loading is to be self-weight plus 5 kPa live load, i.e. when no special storage bays are provided;
− on major bridges where special storage bays, designated by signage, may be provided, general walkway loading may be reduced to 3 kPa live load. The reduced walkway loading is also to be designated by signage;
− on transom top bridges, there should generally be no gap between the end of the transoms and the walkway deck;
− where a grating is required in the 4-foot or on the transom ends, a proprietary material is to be used that will not lift or deform. Products such as expanded metal are not to be used where they are prone to deformation and lifting at the ends, thereby creating a trip hazard or the risk of being picked up by a passing train;
− on excessively wide ballast top deck bridges, i.e. 3 metres and greater from centreline of track to edge of bridge, no discrete walkway will be required. In this case a handrail will be provided up to 4 metres from the centreline of track, irrespective of deck to invert height;
− for through truss/girder bridges, structural elements are permitted to locally infringe clearance requirements when fitting internal walkways subject to a waiver being obtained from Chief Engineer Track. This is preferred to the provision of external walkways, from which a track patroller could not effectively inspect the track;
− the minimum clear walking space is to be 600 mm. Consideration may be given to providing a wider walkway that affords a ‘continuous refuge’, where the particular circumstances (e.g. sighting distances, traffic volumes, bridge length) warrant such provision;
− for transom top bridges, the surface of the walkway is to be at or below underside of transom and not greater than 300mm below top of transom;
− on ballast top bridges, the normal standard is to set the walking surface of the walkway level with the top of the kerb;
− walkway components are to comply with Australian Standards AS 3600, AS 4100 and AS 1657.
C8-2.1.2 Walkway Storage No walkway shall be loaded beyond the design value. If storage requirements exceed this value, storage bays are to be provided and designated by signage. 5 kPa live load equates to 300 kg loading per metre length of 600 mm wide walkway.
C8-2.1.3 Services Services and utilities for RailCorp and external parties shall be located so as not to infringe on the walking or standing areas.
They are to be located to the outside of the walkway and extra width of walkway shall be provided to achieve the minimum walking space specified above.
C8-2.2 Refuges Refuges shall be provided on underbridges over 20 metres in length.
Refuges may be required on bridges less than 20 metres where site conditions warrant their installation.
The distance between refuges is not to exceed 20 metres over the length of the bridge. The spacing at each location is to be determined by a risk assessment, taking account of factors such as train speed, available sighting distances, the existence of warning light systems.
Refuges shall have a minimum clear space of 700 mm depth and 1500 mm width.
To establish the need for refuges and/or signage, the default clearances from the centreline of the nearest track to the front of a refuge are:
− 2230 mm on straight track
− 2500 mm on curved track
RailCorp Engineering Manual — Structures Structures General TMC 300
Where circumstances prevent the installation of refuges and the clearance from the track centreline to the back of a walkway is less than the kinematic envelope (out-of-gauge load) plus 600 mm, warning signs are to be installed as detailed in C8-3.5 below.
C8-2.3 Handrails Handrails are to be provided on the outside of walkways and refuges and also on the opposite side of a ballast top underbridge where the height from deck to invert exceeds 2 metres.
Handrails are to consist of vertical posts together with a top rail and intermediate rail. Specific layouts are to be in accordance with the proprietary specifications of approved suppliers. The height of the top rail is to be not less than 950mm above the deck surface.
C8-2.4 Configurations Typical configurations for walkways, refuges and handrails on underbridges are shown in Appendix 3.
In most situations, walkways will be cantilevered on the outside of both transom top and ballast top structures. In addition, a walking area by way of a grating may also be required on transom top bridges in the 4-foot and on the transom ends.
Walkways shall generally comply with the layout, fixing and componentry detailed on the following drawings:
CV 0041442 Standard Steel Walkway (With Refuge) to suit 9m to 15 m Fabricated Steel Girder Spans
CV 0042333 Standard 1500 Wide Steel Walkway (Without Refuge) to suit 9 m to 15 m Fabricated Steel Girder Spans
C8-2.5 Safety Marking and Signage Safety Marking
Delineation of the ‘safe areas’ to walk and stand on a walkway/ refuge is to be provided by a line 75mm wide and painted in Safety Yellow.
Restrictions on Use Each walkway shall display a sign at each access end showing ‘Authorised Persons Only’. An ‘Authorised person’ is a person authorised by RailCorp or its agents to enter onto and cross rail bridges.
The sign is also to incorporate a warning regarding the restriction on loading.
Details of a typical sign are provided in Appendix 4.
Limited Clearances An additional sign is to be attached to all underbridges with walkways where the clearance from track centreline to the walkway handrail is less than the kinematic envelope plus 500mm. The specification for this sign is provided in Appendix 4. Where similar signs have previously been provided, they should be replaced with the new sign when due for replacement.
C8-3 Bearings and Deck Joints Bearings and joints shall be designed to provide sufficient access for the inspection, maintenance and replacement of the bearings and joints.
The minimum vertical distance between the underside of the main beams and the bearing shelf shall be 500mm.
Jacking points shall be provided on the bearing shelf.
RailCorp Engineering Manual — Structures Structures General TMC 300
The track structure will normally be ballast top or direct fixation. Transom top bridges shall only be used where there are special factors that prevent the use of ballast top or direct fix.
Mechanical rail joints are not permitted on bridges. Anchoring of track and provision for expansion switches shall be in accordance with TMC 231 “Sleepers and Fastenings”.
The noise emitted from the underbridge should be the same level (within ±2 dBA) as that emitted from the track on the approach and departure from the bridge. This requirement applies to bridges in urban areas only. Ballast top structures are deemed to meet this requirement.
New bridge decks, except transom top, shall be structurally continuous without gaps or open joints to prevent matter and debris penetrating the deck within the spans. Where precast beams with gaps are used, there shall be a continuous deck slab rather than joints at the top surface.
Bridge decks installed during refurbishment/replacement of existing bridges shall wherever possible be structurally continuous.
C8-4.2 Ballast Top Ballast top underbridges are preferred to transom top due to ease in maintaining the track and provide for a significant reduction in track degradation adjacent to bridge ends.
The distance between the inside face of the ballast kerb and centre line of track is to be no less than 2150 mm.
The height of the kerb is to be no less than 600 mm. On superelevated track, a wider deck or higher kerb may be required to ensure that ballast is fully retained on the bridge. Ballast shall not spill onto underbridge walkways.
C8-4.3 Transom Top Transom top bridges are generally not to be used for new or replacement bridges. If a transom top bridge is proposed for a particular situation, the prior approval of the Chief Engineer Civil is to be obtained.
C8-4.4 Direct Fixation Direct fixation of the track to bridge decks may be considered where constraints such as limited vertical clearances exist below or above the track.
In situations where the deck is comprised of individual concrete girders with transverse stressing, the track is to be supported on monolithic girders to secure the track gauge.
Direct fixation bridges shall have concrete upstands to prevent a derailed train from falling over the side of the bridge. The upstands shall comply with the requirements of Chapter 7.
If concrete upstands cannot be provided, direct fixation bridges shall have guard rails in accordance with Chapter 7.
Track fastenings shall be approved elastic fastenings.
The maximum height of grout bed under the rail fixings shall be 60 mm. Where the hog of the girders results in a gap under the rail greater than 60 mm high, packers may be used but they shall provide for full lateral restraint to the holding down bolt.
High impact epoxy grouts/mortars or specially developed grouts are to be used under the rails on direct fixation bridge decks to accommodate the high dynamic effects and movement of the deck. There shall be no metallic elements in the epoxy. Standard cementitious grouts shall not be used.
The grout bed shall provide sufficient edge distance to the bolt to avoid cracking of the grout.
RailCorp Engineering Manual — Structures Structures General TMC 300
The transition from ballasted track to the direct fixation bridge deck shall be designed to ensure a smooth transition. Some structural configurations are detailed in Section C8-6 of this manual.
C8-5 Drainage and Waterproofing New underbridges, except transom top bridges, shall have positive drainage systems to prevent water discharging from the bridge to the watercourse or road below. Decks are to be structurally continuous in accordance with Section C8-4.1.
For the refurbishment/replacement of existing underbridges, decks shall where possible have positive drainage systems. Where this is not possible, the waterproofing of the bridge deck is to be achieved by the use of membranes approved by the Chief Engineer Civil, and protected in turn from mechanical damage from the track ballast by the installation of shock mats or similar materials.
Drainage of bridge decks shall generally comply with the requirements of RailCorp engineering standard TMC 421 “Track Drainage”. The drainage system shall be cleanable. The minimum pipe size shall be 225 mm diameter.
Drainage systems shall be designed to capture the water and drain it away from the track structure at the bridge end.
New ballast top bridges shall be provided with a waterproofing membrane to protect the deck concrete. The membrane shall be protected by a ballast mat.
C8-6 Bridge Ends C8-6.1 General
Problems have always existed at the ends of underbridges with regular deterioration of the track “top” or vertical geometry. Other related problems include the loss of ballast profile and fouling of the ballast due to formation failures.
The loss of top may be a result of:
− settlement of the subgrade, owing to inadequate compaction or poor drainage behind the bridge abutment;
− settlement of the track ballast both initially and following maintenance, and particularly settlement relative to the bridge itself;
− additional vibration set up because of the sharp difference in track stiffness between the bridge and the ballasted track;
− ballast losses due to inadequate formation width at the interface with the abutment and exacerbated by the additional vibration;
− wide tie support at the bridge abutment between the last transom and the first sleeper leading to increased forces and impact;
− movement or rotation of the abutment allowing settlement of the fill behind;
− cracking and rotation of ballast walls and wingwalls.
The design of new underbridges and the major refurbishment of existing underbridges shall provide for the stability and compaction of the bridge ends.
This applies to ballast top, direct fix and transom top bridges.
A high level of ballast compaction around bridge ends will assist in their stability and reduce the extent of track settlement. This can be achieved by compaction of the bottom ballast using suitable off track plant prior to laying of the track, and compaction of the top ballast using whacker-packer type equipment or a dynamic stabiliser. Stability of the bridge abutments must be considered before permitting the use of the dynamic stabiliser or off-track rollers.
C8-6.2 Functional Requirements
RailCorp Engineering Manual — Structures Structures General TMC 300
− provide a transition between solid and flexible track support systems;
− maintain the integrity of the ballast profile at the end of the bridge;
− maintain the integrity of the ballast condition;
− maintain the tie support across the interface.
C8-6.3 Approved Configurations RailCorp has approved a number of structural configurations for improving the performance of bridge ends. Selection of the most appropriate configuration for each location will be influenced by the following factors:
− traffic density, tonnage and speed;
− feasibility of implementation;
− whether the improvement is part of a construction, upgrading or maintenance activity.
Typical details and drawings of approved configurations are provided in Appendix 3. These configurations include:
− engineered backfill
− reslilient pads and vibration isolation rail fasteners
− approach slabs
− ballast retention walls
− intermediate rail support on ballast walls.
C8-6.3.1 Engineered Backfill The formation immediately behind the abutments can be constructed in layers of selected compacted fill reinforced with geogrid. Provision shall be made for drainage below the compacted fill.
A typical layout of engineered backfill is shown in Appendix 5.
C8-6.3.2 Resilient Pads and Vibration Isolation Rail Fasteners On transom top and direct fixation structures, resilient pads or vibration isolation rail fasteners may be installed on concrete sleepers on the bridge approaches and on the bridge.
Reference should be made to RailCorp’s standard drawings and layouts for the use of these components.
Timber transoms may be installed instead of sleepers on the bridge approaches to increase the stability of the bridge ends.
The use of concrete sleepers just at bridge ends in timber sleepered areas is not recommended, unless vibration isolation rail fasteners are fitted to the concrete sleepers and transoms.
C8-6.3.3 Approach Slabs A transitional stiffness can be provided between the bridge approaches and the bridge deck itself by the installation of concrete approach slabs.
Where bridges are located on a skew, the end of the approach slab shall be shaped to be perpendicular to the track, to avoid rocking of the sleepers.
Approach slabs may be used in conjunction with track slab and ballast top, transom top and direct fixation bridges. When installed on a ballast top bridge, they should be provided with kerbs lining up with the kerbs on the deck of the bridge.
C8-6.3.4 Ballast Retention Walls
RailCorp Engineering Manual — Structures Structures General TMC 300
Ballast retention walls may need to be installed at bridge ends to prevent loss of ballast from the track. Retaining the ballast profile will reduce the rate of deterioration in the track top and also assist the track’s lateral stability.
Ballast retaining walls may be typically constructed from posts and guardrailing or precast concrete walls. Typical layouts are shown in Appendix 5. Reference should also be made to RailCorp’s standard drawing CV 0115011 Standard Ballast Retaining Wall.
C8-6.3.5 Intermediate Rail Support on Ballast Walls The maximum spacing between the centre of the last sleeper and the centre of the first transom on a bridge should be limited to 600mm.
In situations where centres in excess of 600mm cannot be avoided, a specially designed support must be installed at the ballast wall, enabling the tie spacing to be restored to normal and reducing the forces at the bridge end.
This configuration includes the use of a resilient rubber pad on top of the ballast wall, which provides support to the rail when deflecting under load. A typical layout is shown in Appendix 5. Reference should also be made to RailCorp’s standard drawing CV 0162590 Standard Intermediate Rail Support at Bridge Ballast Walls.
C8-7 Scour Protection C8-7.1 General Requirements
Scour protection is incorporated in the design of new bridges where there has been a previous record of scouring or where a hydrological and hydraulic assessment indicates that there is a potential for scouring around the bridge.
Scour protection may also be required to be provided to existing structures where scouring and damage have occurred. In these instances, reference should be made to the Chief Engineer Civil, to provide an appropriate design for the particular circumstances.
Scour protection is to be designed generally in accordance with the RTA “Bridge Waterway Manual” September 2000 and Austroads “Waterway Design” 1994.
C8-7.2 Culverts Scour protection will not normally be required when any one of the following criteria apply:
− The calculated velocity of flow through the culvert opening at design flow is less than 1.5 metres/per second.
− The bed and banks consist of sound rock or are protected by sound rock bars, and the toe of the embankment is protected.
− The gradient of the channel downstream is flatter than one percent.
− The calculated velocity of flow through the culvert opening at design flow is less than 2.5 metres/per second and the streambed consists of gravel or stones with 50 percent by weight exceeding 150mm.
Geometric considerations may require slope protection where scour protection of the bed is unnecessary.
If scour protection is required downstream of the culvert, it shall extend for a distance not less than 1.5 times the opening height from the end of the culvert. It shall also incorporate a cut-off extending 500 mm below the bottom of the protection or to rock, whichever is the lesser, and shall be carried to the wing walls or up the sides of the channel to at least the serviceability limit states level. Negotiations will be required with adjoining landowners if this requirement results in the scour protection extending outside the railway boundary.
Scour protection shall be specially designed for channels with a grading steeper than one percent.
RailCorp Engineering Manual — Structures Structures General TMC 300
C8-7.3 Underbridges Scour protection shall be provided to footings and pile caps where there is a potential for undermining resulting from scouring of the watercourse under the bridge.
The railway formation around the abutments and wings of a bridge is to be provided with appropriate scour protection where there is a history of scouring and washaways, or where hydrolgical and hydraulic assessments indicate a potential future problem. Similar protection of the railway embankment adjoining the bridge may also be necessary.
C8-7.4 Alternative Construction Materials Alternative forms of scour protection approved for use around culverts and bridges include:
− Grassing of embankment faces;
− Hand placed loose rock (rip rap);
− Sand bags filled with lean grout (e.g. 1 cement to 19 loam);
− Revetment mattresses (concrete filled);
− Gabion baskets or Reno mattresses (rock filled);
− Mortared spall;
− Precast concrete headwalls;
− Cast in situ concrete headwalls;
− Cast in situ concrete aprons and cutoff walls.
C8-8 Protection of Bridges over Roadways Protection of bridges over roadways is to be in accordance with TMC 312 “Underbridge Impact Protection”.
RailCorp Engineering Manual — Structures Structures General TMC 300
Chapter 9 Overbridges and Footbridges C9-1 Lifting of Overbridges
Before lifting an overbridge, a comprehensive work method shall be developed to address the potential effect of the work on the stability of the bridge structure.
In some early bridge designs, the bridge abutments relied on the superstructure to provide lateral support against overturning.
Appropriate investigation of the stability of the structure during and after the lifting process needs to be undertaken as part of the risk assessment.
− The work method must ensure that:
− The bridge is securely constrained against any possible movement during the lifting operation, in particular when any fastenings are removed or ineffective;
− Trestles are secured against lateral movement at the base;
− Jacking operations are undertaken evenly and in small increments (20 mm), with a thorough check of bridge stability undertaken after each stage.
If the bridge is to be lifted clear of its abutments, the bridge ends are to be secured by increasing the height of the abutment wall, or by using diagonal bracing, or by other suitable means.
The detailed work method needs to be approved by a suitably competent civil engineer before undertaking any work.
New bridge decks shall be structurally continuous without gaps or open joints to prevent matter and debris penetrating the deck within the spans. Where precast beams with gaps are used, there shall be a continuous deck slab rather than joints at the top surface.
Bridge decks installed during refurbishment/replacement of existing bridges shall wherever possible be structurally continuous.
C9-2.2 Stepways Stepway riser and tread dimensions for footbridges are to be 150 mm and 300 mm respectively.
Stepway risers are to be closed in to prevent visibility from beneath the structure.
C9-2.3 Barriers, Safety Screens and Protection Screens C9-2.3.1 Definitions
Barriers are defined as the fence or walls along the sides of overbridges and footbridges, installed to protect road vehicles, cyclists and pedestrians from falling over the edge of the bridge.
Safety screens are defined as impenetrable barriers intended to prevent persons from contacting 1500 volt DC equipment and to protect 1500 V DC equipment from damage.
Protection screens are defined as screens installed on overbridges and footbridges to prevent accessibility to a safety screen and to restrict objects from falling or being thrown onto the track below.
C9-2.3.2 Barriers Bridge barriers for new structures and major refurbishments are to be designed in accordance with AS 5100. The barriers provided above the rail corridor shall be at least medium performance level and should be subject to a risk assessment to determine whether a higher performance level is required.
RailCorp Engineering Manual — Structures Structures General TMC 300
The approach barriers to new, extended or refurbished overbridges and footbridges must also comply with AS 5100.
Pedestrian barriers and balustrading for new structures and major refurbishments are to be a minimum height of 1200 mm. Where the bridge provides access to a railway station, the requirements of the RailCorp Station Design Guide are to be accommodated.
C9-2.3.3 Safety screens Safety screens shall be installed to prevent contact with the 1500 V overhead wiring.
For new and refurbished bridges, vertical safety screens shall be used. They shall be insulated from the bridge structure.
Where horizontal screens are attached to the face of the structure on existing bridges, the screen shall be bonded via a spark gap.
Design and construction requirements are detailed in RailCorp Electrical Standard EP 08 00 00 07 SP “Safety Screens for Bridges over 1500 V OHW Equipment”.
Safety screening is also to be provided to footbridge landings, ramps and stairs where they are adjacent to the overhead wiring.
C9-2.3.4 Protection screens Prevention of objects falling or being thrown from overbridges and footbridges shall be achieved by the provision of one of the protection measures listed in AS 5100, including full enclosure (footbridges), provision of solid opaque walls with a minimum height of 2.4 metres, or the provision of protection screens.
Protection screens shall be installed on all new overbridges and footbridges in the 1500 V (electrified) area. They are also to be installed when a bridge or bridge barrier is being replaced.
Attention is to be paid when designing protection screens to the detail at the ends (e.g. adjacent to the abutments), to prevent persons gaining access to the outside of the bridge and then the overhead wiring.
For other existing overbridges and footbridges, the requirement for protection screens is to be assessed on the basis of a risk assessment in accordance with RailCorp’s Safety Management System. The assessment should include a review of incident data. Reference should also be made to RTA Technical Direction TD 2002/RS02 “Policy for Safety Screening of Bridges” for guidance on the risk assessment.
Where required to be installed, protection screens are to be designed in accordance with AS 5100. The design should provide a balance between functionality, aesthetics, effectiveness and value for money, giving due consideration to the following factors:
− Safety for train users/operators: the ability of the screen to prevent objects from being thrown onto the track;
− General safety and train operation: the ability of the screen to prevent trespassers from climbing onto safety screens, thereby endangering their lives and impacting on train traffic;
− Pedestrian amenity: the ability of the screen material and design to provide adequate ventilation, suitable acoustics, light to the inside of the bridge, and views through the screen to the surrounding environment;
− Visual aesthetics: the likely visual impact of the screened bridge as viewed by people in the surrounding area;
− Sharp edges: the design shall minimise any exposed sharp edges on the pedestrian side;
− Modular construction: barrier screens should be designed to be modular, so that individual panels can be replaced;
− Costs: the likely construction and maintenance costs, including initial, ongoing, life span, vandal damage, and graffiti.
RailCorp Engineering Manual — Structures Structures General TMC 300
C9-2.4 Service Ducts Provision may be required for accommodating services owned by RailCorp (e.g. high voltage, low voltage, signalling, communications) or services owned by other authorities and utilities (e.g. telephone, water supply, sewer lines, power and gas).
Ducts are to be provided for both current services and future services where appropriate.
Services shall be segregated where necessary, e.g. power and signalling.
The location and fixing of such service ducts is to be designed so that future access to the services for maintenance is facilitated and access to the main structure for inspection and maintenance is not impeded.
Service ducts are to be provided within the structure (e.g. under footways), in preference to exposed service lines.
C9-2.5 Drainage A drainage system shall be provided on all overbridges and footbridges and shall be directed away from platforms and other RailCorp infrastructure and shall not discharge onto the rail corridor. The drainage system shall be cleanable. The minimum pipe size shall be 225 mm diameter.
C9-3 Deck sheeting Asbestos/fibrous cement deck sheeting is no longer approved for use on footbridges. Where installed on existing structures, it is to be progressively replaced on a programmed basis.
C9-4 Formwork – bondek Permanent formwork located above 1500 V OHW must be of a non-corrosive and non-conductive material, to eliminate the potential safety risk of decay and subsequent contact with the wiring.
No "Bondek" or other similar steel permanent formwork is to be utilised above electrified track or track that may be electrified during the expected life of the structure (approximately 100 years).
Acceptable products for permanent formwork above electrified tracks include fibreglass.
C9-5 Bird Nesting Design features such as spikes may be required to prevent birds nesting on the bridge structure.
C9-6 Electrical requirements Designs shall provide for earthing and bonding of all metallic components on the bridge including reinforcing steel, prestressing steel, barriers, safety screens, protection screens, overhead wiring fittings and utility services.
Refer to Section C4-11 for details.
C9-7 Name Signs C9-7.1 General
Name signs shall be installed on overbridges designated by the Civil Maintenance Engineer.
The name description shall be a readily recognisable name such as Erskineville Road, Pennant Hills Road or Sunnyholt Road.
C9-7.2 Signage Requirements C9-7.2.1 Type of Signage
Name signs shall be painted using stencils and sprayed directly on the designated overbridges.
RailCorp Engineering Manual — Structures Structures General TMC 300
Alternative methods of installing signs, including the attachment of a sheet metal sign, may only be used with the approval of the Chief Engineer, Bridges and Structures.
C9-7.2.2 Location For single and double tracks, the signage shall be installed as follows:
− Bridge abutment or wing wall: to the left of the track as seen by the train driver as the train approaches the structure and vertically between 1500 mm and 3500 mm above rail, or
− Bridge girder, deck or superstructure: to the left of the track as seen by the train driver as the train approaches the structure. The left edge of sign shall not be more than 2000 mm from the centre of the track.
− For locations with more than 2 tracks, the sign location shall be determined on a case by case basis with due consideration of train driver angle of vision, predominant track usage, train direction and other site specific factors.
C9-7.2.3 Detail of Text The stenciling details for the text shall be:
− Black lettering
− White background
− Font type in accordance with AS1744 Series E with Medium spacing
− Font size of 160 mm.
The paint/spray shall be retro reflective.
At locations where vandalism may be an issue, signs are to have an anti-graffitti coating applied.
Typical details are:
E R S K I N E V I L L E R D
N O R T H K I A M A D R
Figure 4
2260
160
2250
Issued July 2010 UNCONTROLLED WHEN PRINTED Version 2.2
160
RailCorp Engineering Manual — Structures Structures General TMC 300
Chapter 10 Overhead Wiring Structures and Signal Gantries C10-1 Existing Structures
Where existing overhead wiring structures or signal gantries require refurbishment or replacement, the opportunity is to be taken to design the replacement/ refurbished structure in accordance with the current and proposed future line usage and business requirements.
In these instances, field requirements are to be referred to the Chief Engineer Civil for detailed design.
C10-2 General Design Requirements To minimise maintenance, overhead wiring structures and signal gantries are to be configured using smooth, clean faced structures without a proliferation of small members, fittings and metal to metal interfaces.
In addition the following design criteria will apply:
− the minimum thickness of major steel structure components is to be 8 mm;
− steel structures and fittings are to be galvanised, unless approval is given by the Chief Engineer Civil to use alternative coatings (e.g. coatings to meet heritage requirements);
− the minimum size of fillet welds is to be 6mm;
− designs must ensure that moisture and debris collection pockets are not created;
− the top surface of footings and holding down bolts are to be clear of the track ballast, cess and sub grade levels;
− the structures are to be designed for a serviceable life of 100 years.
C10-3 Standard Structures A range of standard overhead wiring and signal gantry structure types exists within the RailCorp system. Refer to Appendix 6 for a list of standard drawings.
The standard structures listed in Appendix 6 are drawings that provide standard fabrication and construction details. All standard drawings must be read in conjunction with a structure diagram containing details for a specific location. A competent Engineer (certified structural) must undertake the design for each structure, determine which standard structure type if any is suitable for the location under consideration, produce the structure diagram and have the design verified.
Both strength and serviceability limit states must be satisfied. A standard structure cannot be simply nominated for multiple locations over a particular span because the loading from the overhead wiring varies significantly depending on the wiring system in use, distance between structures, number of wires being connected, the radius of the track and out-of-running or anchor wire angles. All these design loads, along with wind load, need to be considered when a structure type is nominated from the above list.
A large range of structure sizes is available for use and the designer must nominate the most economical structure for the location under consideration. Preference shall be given to SHS portals before nominating double PFC portals or double UB portals.
If existing standard structures are not suitable for a particular location, then a non-standard structure can be used provided approval from the Chief Engineer Civil is obtained.
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Existing tunnels within RailCorp’s network may not conform to current standards and policies with respect to emergency procedures in the event of a major irregularity (e.g. fire or derailment etc.).
The Chief Engineer Civil will determine whether additional emergency facilities are to be installed in the existing tunnels.
C11-2 Refuges General policies and procedures with respect to the provision of refuges in tunnels are covered in Chapter 6 of this Manual.
C11-3 Provision for Services Provision may be required when designing tunnels for accommodating services owned by RailCorp (e.g. electrical and signalling cables) or services owned by other authorities and utilities.
Services are to be positioned in accordance with the following requirements:
− Transit space standard ESC 215;
− Clear of any walking areas where they might present a trip hazard;
− Not to interfere with or obstruct emergency walkways;
− Not to obstruct access to or reduce the capacity of refuge areas.
The location of any services is also to be selected so that future access for maintenance of the services is facilitated.
Other specific requirements for cabling in tunnels are detailed in Section 10.11 of this Standard.
C11-4 Drainage Drainage systems shall collect and dispose of any groundwater and rainwater that enters the tunnel in order that the track infrastructure is kept well-drained and maintenance costs minimised.
Seepage of groundwater can cause corrosion to structural elements of the tunnel and overhead wiring. Appropriate measures are to be implemented to protect these components from corrosion.
C11-5 Tunnel Invert The migration of fines into the tunnel from within the rock mass beneath the tunnel invert must be prevented by appropriate invert treatment.
C11-6 Seepage and Drainage The rate of inflow of groundwater into the tunnel is to be limited in order to not adversely affect surrounding property and infrastructure caused by changes to the groundwater level and flow regime.
The rate of inflow into the tunnel must also be controlled to avoid impact to any existing surface water courses.
The seepage rate of water into the tunnel shall be limited to a maximum of 0.1 litres/second per any continuous 100m length of single track tunnel.
Drainage systems shall be designed to collect and dispose of any seepage and surface water that enters the tunnel in order that the track infrastructure is kept well-drained to minimise maintenance.
The drainage system shall be configured so that in the event of a blockage, any overflow will not affect train operations or the reliability of the infrastructure.
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All drainage discharge from the tunnel shall be treated to be of such quality as to meet the requirements of the relevant authority for discharge to the stormwater system.
The drainage system design and configuration shall consider the need for maintenance staff to access adjacent equipment without having to stand in the drain.
No water seeping through the tunnel structure is to drip onto the track.
C11-7 Tunnel fittings Seepage of groundwater can cause corrosion to structural elements of the tunnel and overhead wiring. Appropriate measures are to be implemented in the design to protect these components from corrosion.
All fittings and fastenings securing overhead wiring and other services to the tunnel structure are to be stainless steel grade 316 to AS 1449 “Wrought alloy-steels – Stainless and heat-resisting steel plate, sheet and strip”.
Mechanical and chemical anchors should be designed and installed taking into account the long-term strength of the natural ground and tunnel linings allowing for deterioration over time.
C11-8 Stray Currents Tunnel linings and fittings shall be designed to mitigate the effects of stray currents from the overhead wiring system.
C11-9 Name Signs C11-9.1 General
Name signs shall be installed on tunnels designated by the Civil Maintenance Engineer.
The name description shall be a readily recognisable name such as Zig Zag No. 5 or Woy Woy Tunnel.
C11-9.2 Signage Requirements C11-9.2.1 Type of Signage
Name signs shall be painted using stencils and sprayed directly on the designated tunnels.
Alternative methods of installing signs, including the attachment of a sheet metal sign, may only be used with the approval of the Chief Engineer, Bridges and Structures.
C11-9.2.2 Location For single and double tracks, the signage shall be installed as follows:
− Tunnel approach: to the left of the track as seen by the train driver as the train approaches the structure and vertically between 1500 mm and 3500 mm above rail, or
− Tunnel approach: to the left of the track as seen by the train driver as the train approaches the structure. The left edge of sign shall not be more than 2000 mm from the centre of the track.
− For locations with more than 2 tracks, the sign location shall be determined on a case by case basis with due consideration of train driver angle of vision, predominant track usage, train direction and other site specific factors.
C11-9.2.3 Detail of Text The stenciling details for the text shall be:
− Black lettering
− White background
− Font type in accordance with AS1744 Series E with Medium spacing
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Chapter 12 Retaining Walls and Platforms C12-1 New Retaining Walls
From time to time, it may be necessary for maintenance staff to install a new retaining wall, to rectify a land slip or to provide additional clearances for maintenance purposes.
All retaining walls over 900 mm high are to be referred to the Chief Engineer Civil for structural design.
For retaining walls within 3 metres of a track centreline, the top of the footings shall be located at least 1 metre below rail level. This will permit the proper functioning of cess drainage and future ballast cleaning and track reconditioning activities.
Designs are to include appropriate provision for drainage (e.g. top drains and weep holes).
Provision will need to be made for a safety handrail on top of a retaining wall where the wall height exceeds 2 metres.
C12-2 Refurbishment and Replacement Where existing retaining walls or station platforms require refurbishment or replacement, the opportunity is to be taken to design the replacement/ refurbished structure in accordance with the current and proposed future user requirements. An example is a platform wall that has a sub-standard height or which impedes the track drainage. Field requirements should be referred to the Chief Engineer Civil for detailed design.
C12-3 Surface Finishes At locations where vandalism may be an issue, walls shall have an anti-graffitti coating applied.
Where shotcrete is used in refuges, the shotcrete surface shall be steel-floated.
C12-4 Earthworks Earthworks associated with the backfill of retaining walls and station platforms are to be designed in accordance with AS 4678 “Earth-retaining structures” for compaction and drainage.
C12-5 Temporary Platforms The provision of temporary station platforms may be required during new construction works or as part of major maintenance work.
If a temporary platform is required to be in service for twelve months or more, it is to be designed for full loading requirements as detailed in standards.
If a temporary platform will be required for less than 12 months, relaxation of the loading requirements may be allowed.
C12-6 Platform Configuration and Drainage Platform ends are to be finished vertically; ramped ends are not permitted as they facilitate the mounting of the platform by a derailed train.
The length of platforms is to be determined on the basis of operating requirements and likely future requirements for passenger train consists, and in accordance with the RailCorp Station Design Guide.
The height of platforms shall be in accordance with ESC 215 “Transit Space”.
The width of platforms is to be determined on the basis of usage requirements and in accordance with the RailCorp Station Design Guide.
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Platform surfaces (including temporary platforms) are to be constructed in durable and impermeable materials that will resist warping, slipping and tripping.
Unrestrained earth slopes beneath open platforms are to be designed to prevent spillage of material onto the track.
Vertical platform walls or piers adjacent to the track are to be placed no closer than 750 mm to the edge of the cantilevered coping, to allow for adequate ballast profile and drainage.
Track drainage is to be specifically designed at platforms, particularly in cases where natural run-off from the track structure is interrupted by the platform wall. Where practicable, the top of the footings should be located a minimum of 1 metre below rail level, to facilitate future ballast cleaning and track reconditioning and to ensure that the platform is not undermined during such activities.
The slope of the platform surface is to be designed so that run-off is directed away from the track. A positive drainage system is to be provided to collect and dispose of all stormwater.
C12-7 Platform Copings The lateral and vertical placement of platform copings in relation to the track is to be in accordance with ESC 215 “Transit Space”.
Coping materials are to be designed to be non-conductive.
When refurbishing an existing platform coping, a steel edge may be used subject to the installation of an insulating material to the top of the steel edge. Paint shall not be used as insulating material.
The use of other materials including fibreglass is subject to the approval of the Chief Engineer Civil.
C12-8 Services For new structures, services shall be located within utility ducts within the platform.
For existing structures, services, such as cables and ducting, may be attached to the platform wall under the coping. Services shall preferably be located no lower than 500 mm from the underside of the coping and extend laterally no more than 300mm from the platform wall towards the track.
C12-9 Excavation and Upgrading Works C12-9.1 General
Reference should be made to Section C4-9 of this Manual for procedures and restrictions relating to excavation works in the vicinity of platforms and retaining walls. Particular care must be taken to avoid disturbance to or destabilisation of existing structural footings and underground services.
C12-9.2 Platforms When undertaking excavations or other civil works on filled station platforms, there is a risk that the platform wall may be destabilised owing to the weight of heavy plant exerting undue pressure on the back of the wall. All motorised plant (with the exception of light equipment) must therefore not be used within 1.5 metres from the rear face of any earth retaining platform wall.
While excavating in filled platforms, damage may also be sustained to ground anchors that may have been installed to support the wall. The anchors typically come in the form of round steel bar or old rails, extending either horizontally or sloping downwards from the top of the wall and terminating in a concrete block. Whilst it is useful to consult old platform details, it is inconclusive to rely on these being ‘work as executed’ and care must therefore be taken when excavating.
It may be necessary to prop a platform so that it can be secured during upgrading works on the platform. Platforms with brick walls must be propped for work involving the use of heavy motorised plant. Other platform walls require assessment by a structural engineer.
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The sample design for propping detailed in Figure 6 is suitable for platform resurfacing works involving the use of a 2 tonne non-vibratory roller. If a heavier roller or a vibratory roller is to be used, a propping system shall be designed and approved by a person with the appropriate design authority.
SAMPLE ONLYNot to be used without
design approval
Figure 6 – Sample propping details
C12-9.2.1 Track Requirements If the propping system utilises the track structure, propping must be from the rail nearest the platform and the approval of the Chief Engineer Track is required.
If the propping design in Figure 6 is to be used, the following track requirements must be met:
− No rail traffic is to operate on track where propping is placed
− The track situation must be reviewed by a qualified Track Examiner and the Civil Maintenance Engineer must be consulted
− Propping is not to be used in the Summer period (November to March) if the work location has Priority One WTSA ranking. Propping would impose an unacceptable risk for the track section.
− If the track structure has concrete sleepers and the ballast profile and ballast condition is good, an Engineering waiver is not required.
− If the track structure has timber sleepers in good condition, with 100% resilient fastenings and the ballast profile and ballast condition is good, an Engineering waiver is not required.
− If timber sleepers are fastened with lock and dogspikes or dog screws the track has to be reviewed on a case by case basis and an Engineering waiver will be required before work can commence.
C12-9.2.2 Controls Control measures will be required for work on the platform when propping is used.
The control measures for work involving the sample propping design include:
− Asphalt compaction equipment MUST NOT exceed 2 tonnes fully loaded
− The compaction equipment MUST be non-vibratory
− NO work is to be undertaken on the track whilst the propping is in place. No machinery is to pass over the track unless work on the platform ceases. The machinery passing over the track must be directly supervised and the track checked for any damage to the propping prior to work on the platform resuming
− The platform coping MUST be monitored by a surveyor for lateral deflection during construction
Issued July 2010 UNCONTROLLED WHEN PRINTED Version 2.2
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− The track MUST be inspected and certified by a qualified Track Examiner after completion of the work. Any track movement or disturbance must be reported to maintenance staff
− Patrol staff MUST inspect the site closely for disturbance during regular patrol
− Screw jacks MUST NOT be over-tightened (snug tight only).
C12-9.2.3 Responsibility of Works Supervisor It is the responsibility of the person supervising the platform work to ensure that the track requirements are complied with and that the control measures are implemented.
The supervisor shall liaise with the possession manager, the Civil Maintenance Engineer and others as required.
If no work is to be undertaken on the track, the supervisor must make arrangements to prevent it.
If track patrol staff are to check for track movement, they need to be instructed to do this by the Civil Maintenance Engineer.
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Chapter 13 Miscellaneous Structures C13-1 Overhead Service Crossings
Overhead service crossings are free-standing structures carrying utility services such as water or sewer mains.
Requirements are:
− design of the structure is to be such that the number of elements that are likely to be struck by a derailed train is minimised. Any columns at track level supporting the structure are to comply with the requirements for pier and column protection;
− access to RailCorp’s infrastructure must be maintained as specified for the particular site;
− provision must be made for any future railway track advised by RailCorp.
C13-2 Noise Barrier Walls Noise barrier walls are structural elements erected for the purpose of attentuating the transmission of train noise to adjacent properties. They may be installed adjacent to the rail lines or along the rail corridor boundary.
The barriers are to be designed so as to provide access for maintenance and access to other rail infrastructure.
C13-3 Rockfall Shelters The stability of railway cuttings may deteriorate over time, resulting in the risk of earth slips and rockfalls over the track.
The collapse of cuttings or earth slips may be rectified under normal circumstances with remedial earthworks or techniques such as shotcreting etc. Where this type of action is not possible (e.g. because of access difficulties or height of cutting etc.), it may be necessary to consider the installation of a rock shelter structure to protect the track.
Rockfall shelters protect the track from falling rocks. The need to provide a rockfall shelter shall be determined by a geotechnical risk assessment.
Rockfall shelters and supporting elements such as columns shall be designed to resist impact loads from falling rocks. The design loads are to be determined on a site specific basis.
Where rockfall shelters are to be constructed, the vertical clearance between the ultimate approved rail level and underside of structure, and lateral clearance beside the tracks, are to be as specified in ESC 215 “Transit Space”.
Where applicable, provision is to be made for ‘safe areas’ for infrastructure staff to gain refuge from a passing train in accordance with Chapter 6 of this document.
The design shall consider the future maintenance of the rockfall structure and the roof shall be designed for any temporary plant and equipment required for maintaining the roof.
C13-4 Lighting and Communications Towers The design loads for lighting and communications towers shall be in accordance with the relevant Australian Standards for the type of structure.
The towers shall be designed and configured to meet the functional and performance requirements specified for each site by the tower owner.
C13-5 Structures Over & Adjacent to Tunnels Structures to be constructed over and/or adjacent to tunnels are to be suitably designed to take account of the interface with the tunnel.
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Work methods shall be designed, staged and monitored to avoid damage to the railway tunnel. Work method statements are to be approved by RailCorp personnel with appropriate engineering authority.
Prior to the commencement of works, a dilapidation survey of the tunnel and other rail infrastructure in the vicinity of the proposed works shall be undertaken. The existing condition of the rail infrastructure is to be agreed and recorded.
During construction works, the maximum peak particle velocity in the tunnel lining shall not exceed 20 mm per second.
Before commencing excavation within 5 metres of the tunnel, vibration monitors are to be installed inside the tunnel as close as possible to the point of excavation. Any cracks generated in the tunnel lining are to be monitored during excavation and repaired on completion of the work.
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Chapter 14 Air Space Developments C14-1 Existing Developments
Many existing airspace developments do not comply with the provisions of AS 5100 with respect to collision loading and protection.
If the air space development structure has an alternative load path available, no additional protection is required.
If an alternative load path is not available, the supports are to be subjected to a risk analysis. Reference should be made to Chapter 5 of this Manual with respect to the undertaking of risk assessments and implementation of additional protective measures.
C14-2 Refurbishment of Existing Developments Where major refurbishment of an existing airspace development is proposed, the structure is to be treated as a new development and the provisions of C14-3 are to be applied.
Major refurbishment works are defined to include:
− any alterations to the columns or supports;
− anything which increases the load on the columns or supports;
− any works which increase the height of the building;
− any works which will increase the level of patronage to the development;
− any refurbishment to buildings within the development that in the opinion of RailCorp is not insignificant or minor such as refurbishing an individual shop. For the avoidance of doubt, if there are several shops being refurbished at or around the same time, such refurbishments will be accumulated and will be considered as a whole rather than individually; and
− any other works or refurbishment that in the opinion of the RailCorp is of a major nature.
C14-3 Design Requirements C14-3.1 General
The following requirements shall be met by any air space development over RailCorp’s infrastructure:
− the development must satisfy all Local Government, State, and Federal Authority requirements without any concession for being on railway land;
− the development shall comply with RailCorp’s specified noise, vibration and track drainage requirements;
− planning should allow for up to twelve months’ notice where track possessions and/or electric traction power outage are required for construction;
− preliminary and detailed drawings and specifications for the proposed development are to be submitted to RailCorp for comment and acceptance.
C14-3.2 Access The following access requirements must be incorporated in the design:
− where the existing access by the rail authorities or the public between a station and the adjacent public streets is proposed to be changed, the Developer must obtain written approval for the suitability and capacity of passageways, steps, escalators, etc.
− approved arrangements must be made for access of commuters and workers to island platforms, and for workers’ areas between tracks.
− access to RailCorp’s facilities must be maintained as specified for the particular site.
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C14-3.3 Site Considerations Developers must fully investigate ground conditions and any peculiarities of the site.
RailCorp accepts no liability for generation of noise and vibration by normal railway operations (including track maintenance), or for its transmission into buildings or structures built over or adjacent to the track area. All aspects of noise must be investigated including reverberation in any enclosed railway air space.
Subject to RailCorp’s agreement, development proposals may provide for complete or substantial removal of existing buildings and/or structures from the platforms and affected areas, in the interest of better access and column locations. If such a course of action is proposed then the cost of temporary and ultimate relocation of the displaced activities to the satisfaction of RailCorp shall be borne by the Developer.
C14-3.4 Clearances to Railway Tracks Horizontal and vertical clearances for air space developments are to comply with RailCorp Engineering Standard ESC 215 “Transit Space”.
Provision must be made for any future railway track advised by RailCorp.
On platforms, the minimum clear space between the track centreline and any supporting structure is to be as specified in the Transit Space Standard.
No part of the development shall intrude inside the clearance lines without the specific approval of RailCorp.
C14-3.5 Services The proposed development must make full provision for supporting, relocating, and accommodating all existing and foreseeable future services (RailCorp and utility) to and on the site. The Developer is to meet the cost of such installations and alterations. The location of services is to be designed so that future access for maintenance is facilitated.
Services shall not be located below the underside of the floor of the airspace development above the rail corridor and equipment.
Openings or penetrations above the overhead wiring are not permitted.
Gas, water, drainage, sewerage, mechanical, telephone, data, or electrical services for the development shall be housed in service ducts and brought down to ground level, preferably at the street boundary.
Drainage shall not be suspended above the track and shall not discharge into the rail corridor.
Plans of such services showing their construction and locations are to be submitted to RailCorp for approval before any work on their installation is commenced.
C14-3.6 Fire Rating For new developments, the portion of the structure adjacent to and over the tracks is to be fire rated to the satisfaction of RailCorp, and is to be capable of isolating the track and platform area from fire in the superstructure.
A 4-hour fire resistance level must be provided between RaiICorp infrastructure and the air space development.
For refurbishment of existing developments, the appropriate fire resistance level is to be determined under the ‘fit for purpose’ provisions of the Building Code of Australia.
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C14-3.7 Seismic Loading Airspace developments are classified as Type III, i.e. essential to post-earthquake recovery, for design for seismic loading.
C14-3.8 Electrical Requirements To limit the transfer of stray traction currents from the electrified tracks to the surrounding area, it will be necessary for all metallic service pipes installed in the development to be insulated electrically from the street mains by insulating joints or other approved means, and for the electrical installation of the building to be so designed that the above provisions would not be short circuited by the connection of the neutral conductor.
All plans and specifications for the installation shall be forwarded for RailCorp’s approval before commencing the work. RailCorp will, however, not accept any liability whatsoever for the transfer of any stray current to the development structure.
Where applicable, the Developer is to make provision for the attachment of overhead wiring supports and safety screens, particulars of which will be supplied by RailCorp.
The electricity supply required for the development shall be obtained by the Developer from the Local Supply Authority. In general, this may entail a substation dedicated to the development, with isolating transformers separating the electrical installation within the development from the Local Authority’s mains.
C14-3.9 Lighting and Ventilation All RailCorp property covered by the development is to be illuminated to adequate levels as required by the Australian Standards. Additional lighting may be required because of “tunnel” effects.
All RailCorp property affected by the development is to be suitably ventilated and/ or air conditioned to comply with AS 1668 and appropriate Local Council Health Code requirements.
Where a public entrance between a railway station and an adjacent public street is through the development, an emergency lighting circuit connected to the RailCorp supply is to be provided to light the access in the event that the supply to the development fails.
C14-3.10 Aesthetics All visible surfaces of station-level buildings, structures, columns, etc., provided or upgraded as part of the development are to be architecturally designed and treated to produce a modern public amenity of pleasing appearance at no cost to RailCorp.
The decking over the track shall be of reinforced or pre-stressed concrete construction and there must be no exposed pipe or service component of the building visible from below.
C14-3.11 Protection of RailCorp Property The development is to be constructed in such a way that prevents objects or materials being thrown, dropped, or falling due to accident, onto a track or platform from any portion of the structure.
The structure is to be designed so that the structural integrity of the platform and concourse levels is retained in the event that significant damage occurs to the structure above.
The structure is to be designed so that it can be demolished to the level of the “deck” or “roof” over the railway tracks, platforms, and access ways, without disturbance to rail operations or commuters.
The Developer is required to obtain RailCorp’s approval for the method by which the “deck” or “roof” over the railway tracks and platforms may be constructed or demolished.
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The Developer, prior to being given final approval to commence construction, must enter into a legal agreement to indemnify RailCorp against all loss or damage to RailCorp’s property and all claims that occur as a result of the development.
All RailCorp property must be fully protected during construction and all site work including clearances to the tracks must conform to RailCorp’s Transit Space Standards and safe working requirements.
All construction carried out on railway property shall comply with the requirements of the relevant Authorities and legislation including OHS and environmental requirements.
C14-4.2 Dilapidation Surveys Prior to the commencement of works and prior to the issue of an Occupation Certificate, a joint inspection of the rail infrastructure and property in the vicinity of the proposed works shall be carried out by representatives of the Developer and RaiICorp. The existing condition of the rail infrastructure is to be agreed and recorded.
Any impact on the rail infrastructure is to then be monitored during the implementation of the works. The submission of detailed dilapidation reports may be required as a result.
Particular attention is to be given to proposed developments in the vicinity of rail tunnels. In such instances, joint inspections by the Developer and RaiICorp shall be required prior to the commencement of the works, during the works, prior to the issue of the Occupation Certificate and following occupation.
C14-4.3 Risk Assessment A Rail Related Risk Assessment Plan and Safe Work Method Statements are to be submitted by the Developer for RaiICorp’s approval prior to commencing any works on site.
The Rail Related Risk Assessment Plan shall be prepared in accordance with the RailCorp Safety Management System and shall address the following:
− An identification of both hazards and risks to both the development and RailCorp’s facilities;
− A risk ranking in accordance with the Safety Management System;
− Controls showing how the risk to RaiICorp’s facilities will be managed.
The Safe Work Method Statements are to detail the following:
− Detailed work methods including the incorporation of the controls as stated in the Risk Assessment Plan;
− An emergency response plan.
C14-4.4 Demolition, Earthworks and Construction Impacts The demolition of any existing air space developments is to be planned in such a way that there is no risk of debris falling onto the rail lines or other RailCorp facilities. If such a risk cannot be fully eliminated, the Developer shall be required to take every possible action to minimise the risk and will be required to meet the costs of any protection of the rail infrastructure, disruption to rail operations and removal of the debris.
The impact of any proposed excavation work is to be assessed to ensure that the rail lines and other RailCorp facilities are not undermined or destabilised. Similarly, any ground filling works are to be planned and designed so that there is no risk of collapse onto the adjoining rail lines during construction.
Ground vibrations that may result during any demolition works or earthworks are to be assessed to ensure that there will be no adverse effects on RaiICorp’s facilities. If large-scale demolition,
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excavation or filling work is involved, the Developer shall be required to install a vibration monitoring system to monitor vibration levels in the vicinity of the adjacent RailCorp facilities.
Hydraulic rock breakers are not to be used within 5 metres of any railway tunnel.
The Developer shall be required to arrange a structural investigation by an appropriately qualified person to address the above impacts. The safeguarding of RailCorp’s facilities is also to be included by the Developer in his general construction and demolition plans, risk assessment and Work Method Statements.
C14-4.5 Drainage and Pollution Control During construction, the Developer is to observe extreme care to prevent water from collecting on or near the rail infrastructure. If rail services are disrupted by drainage from the development, the Developer shall be liable for any expenditure incurred by RaiICorp in restoring or maintaining alternative services.
The Developer shall also take extreme care to prevent the release of any form of pollution from the development and will be responsible for the removal and rectification of any damage arising from pollution.
C14-4.6 Electrical Restrictions Minimum safe working clearances to electrical power lines and equipment located within the rail corridor are to be observed in accordance with WorkCover and RailCorp Safety Management System requirements.
This relates to:
− Persons, tools, equipment and material
− Metal ladders
− Cranes or Plant
− Scaffolding
− Metal measuring tapes
− Excavation or boring near electrical underground cables.
C14-4.7 Crane and Other Aerial Operations During construction, the use of cranes and other equipment in the vicinity of any overhead wiring or transmission lines must be strictly controlled. The Developer shall demonstrate to RaiICorp that all crane and other overhead operations will be properly managed, and enter into an agreement with RaiICorp for such operation.
Minimum working clearances for cranes and other aerial equipment to exposed electrical equipment within the rail corridor are prescribed in Clause 14-4.6 above.
C14-4.8 Track Possessions and Power Outages On any occasion where construction activity necessitates the stopping of trains or isolation of electrical supplies, the Developer shall be required to meet all associated costs incurred by RailCorp.
It should be noted that planning and arrangements for track possessions and electric traction power outage are on a long-term basis requiring up to twelve months notice.
C14-5 Information to be Supplied at the Design Stage The following documentation as a minimum shall be submitted by the Developer with a development proposal to RaiICorp:
− Full survey details in both hard copy and electronic form, locating the development with respect to the railway boundary and rail infrastructure;
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− Details of a services search, identifying any rail services or infrastructure affected by the development both within and outside the railway corridor;
− A report covering environmental issues and proposed protective measures during both construction and ongoing use of the development, including noise, vibration, air quality, water quality and pollution control.
− In electrified areas of RaiICorp’s network, a report on Electrolysis Risk and measures proposed to safeguard the proposed development from damage;
− Details of proposed lighting, signs and reflective materials visible within the rail corridor;
− If applicable, a heritage impact statement;
− If a building or structure is proposed to be located within 20 metres of an operational rail line, details of proposed collision protection and, where required, a risk assessment of damage from a derailed train;
− Future maintenance plan for the development where impacting on RaiICorp’s facilities.
C14-6 Documentation to be Submitted Prior to Construction The following documentation shall be submitted by the Developer to RaiICorp as appropriate, prior to the commencement of construction:
− Dilapidation survey report;
− A Rail Related Risk Assessment/ Management Plan and detailed Safe Work Method Statements for all demolition works, earthworks, drainage and building construction etc.;
− Details of all proposed cranage and other aerial operations;
− Environmental management plan with respect to safeguarding the rail corridor.
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Chapter 15 External Developments C15-1 General Requirements
Developers proposing new developments adjacent to the railway corridor will be required to plan the development so that there will be no adverse effects on the rail infrastructure or rail operations.
Issues to be taken into consideration by the Developer will include the impact of the proposed development on the stability and safety of RaiICorp’s facilities, electrical clearances and restrictions, noise and vibration, drainage, foundations within the rail corridor, boundary fencing and security, landscaping and lighting, future rail works, impact on existing level crossings and rail user facilities, and general safety during the construction and ongoing use of the development.
Proposed new developments adjacent to the railway corridor shall comply with the provisions of ESC 380 “External Developments”.
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Timber planks used to retain the filling behind an abutment.
APPROACH SLAB Slab (usually reinforced concrete) laid above the formation behind bridge abutments and designed to provide a transition zone for track stiffness onto the bridge.
B
BALLAST KERB Longitudinal member at the outer edge of a ballast top span to prevent ballast spilling over the side.
BALLAST LOG Timber, masonry or steel member sitting on top of the abutment ballast wall to hold back track ballast.
BALLAST RETENTION WALL
Longitudinal member at the bridge end to retain the ballast profile.
BALLAST TOP Underbridge with continuous deck supporting metal ballast.
BALLAST WALL Top part of the abutment wall to hold back earthworks and track ballast.
BARRIER The fence or walls along the sides of overbridges and footbridges, installed to protect road vehicles, cyclists and pedestrians from falling over the edge of the bridge.
BEARING Seating area of a load-carrying member; may be a separate fabricated member attached to the girder ends.
BODY BOLT Vertical bolt in timber girders and corbels causing pairs of members to deflect together.
BRACING Horizontal or diagonal member attached to main members to stiffen those members, or to minimise sidesway.
BRIDGE A structure spanning a river, road, railway, or the like, and carrying vehicles, persons or services.
BROAD FLANGE BEAM
A steel girder designed in the 1920’s with thicker and wider flanges and reduced height of web for use in locations where greater vertical clearance was required.
BUFFER STOP Structure provided at the end of a rail line or siding to prevent rolling stock from running off the end of the track and/or colliding with an adjacent structure.
BUTT TRANSOM Intermediate transom linking the ends of girders from adjacent spans.
C
CAISSON A cylinder or rectangular ring-wall for keeping water or soft ground from flowing into an excavation. It may later form part of the foundation.
CAPPING Impermeable layer of fill located immediately above the main formation and designed to shed water to the sides of the track.
CATCHMENT Area of land from which water flows into an underbridge.
CHECK A separation that runs parallel to the timber grain and usually on the surface. It results from stresses that develop as the surface layers of wood loose moisture.
COMPOUND GIRDER Timber girder made from two or more sections bolted firmly together on top of each other.
RailCorp Engineering Manual — Structures Structures General TMC 300
The face of a member that is in compression. For beams it is usually the upper face and in particular near mid-span. For a cantilever or a continuous member it is the lower face over the supports.
COPING The longitudinal edge of a station platform.
CORBEL Short longitudinal member seated on a headstock providing a bearing for adjacent girders.
CORROSION The gradual removal or weakening of metal from its surface by chemical attack. Generally, it requires the presence of water and oxygen, and is helped by carbon dioxide, sulphur dioxide and by other materials in small quantities in the air or water.
CRACK Open fissure on the surface of a member, but not necessarily right through the member.
CULVERT Arch, box-shaped or piped underbridge having integral walls, roof and floor.
D
DAMAGE The sudden worsening of the condition of a structure, its elements and component materials due to the effect of a sudden event such as fire, flood, accident or vandalism.
DEBRIS Rubbish or other loose material lying near an underbridge and which impedes smooth water flow through the bridge opening, or collected against a structure.
DECAY Deterioration on or in a timber member causing loss of strength.
DECK Part of bridge superstructure directly carrying the load.
DEFECT Deterioration of a member of a structure from its original condition.
DEFLECTION Downwards displacement or sag of a bridge girder when loaded by vehicles or persons, or displacement of a structure from its design position under load.
DEFLECTION WALL Structural wall installed to protect the supports of a structure adjacent to the track from collapse caused by a derailed train.
DEFLECTOMETER Instrument for measuring deflection in girders - also referred to as “mousetrap”.
DETERIORATION The gradual worsening of the condition of a structure, its elements and component materials due to the effects of traffic and other loadings, the action of the environment on the structure and/or the actions of the constituents of component materials over a period of time.
DIVE Form of tunnel where one rail track passes under another track that is located at ground level
DRIVING MARK Mark cut into (timber) pile indicating in roman numerals the distance to the pile tip.
E
ENHANCEMENT The improvement of the condition of a structure above its design or initially planned level of service. Forms of enhancement include strengthening, widening, lengthening, raising and improved safety such as better barriers.
F
FLOOD LEVEL Mark stencilled on No.1 Abutment of underbridges indicating height and date of maximum previous flood.
FOOTBRIDGE Bridge over the track carrying pedestrian traffic only. May be freestanding or combined with an overhead booking office.
RailCorp Engineering Manual — Structures Structures General TMC 300
FOOTWAY Pedestrian access attached to, or included in, an overbridge.
FORMATION Ground immediately beneath the capping and track.
FLYOVER Bridging structure where one rail track passes over another which is at ground level.
G
GANTRY An overhead structure consisting of side masts or columns joined at the top by a horizontal bridging member.
GIRDER Horizontal main load-bearing member of a structure supporting the remaining components of the superstructure.
GUARD RAIL Old rail or steel angle, placed in pairs, fixed to transoms or sleepers between the running rails to guide derailed wheels across an underbridge/vulnerable site.
H
HANDHOLD DEVICE A system of handrails provided along a wall structure to provide support for personnel.
HEADSTOCK Horizontal member(s) attached at or near the top of a trestle or pier, on which the superstructure bears.
I
INTERMEDIATE
TRANSOM
Timber transverse member set between top and bottom girders in a ballast top span.
INVERT Base or floor of a structure.
J
JACK ARCH Form of bridge decking in which small concrete or masonry arches infill run between main longitudinal steel girders.
M
MAINTENANCE The actions necessary to preserve the serviceability, reliability and safety of a structure at or near its current level and to slow the rate of deterioration.
MAST An independent vertical column located adjacent to the track for the support of overhead wiring etc.
MINOR OPENING Underbridge less than 10 metres in length.
O
OBVERT Underside of bridge superstructure.
OVERBRIDGE Bridge carrying road vehicles or livestock over a track.
P
PACKING Piece of timber, steel, or other hard material, placed or driven between members to adjust their relative position.
PARAPET A type of barrier comprising a solid wall or post and rail fence along the sides of overbridges and footbridges, installed to protect road vehicles, cyclists and pedestrians from falling over the edge of the bridge.
PIER Intermediate support of bridge spans between abutments, built of solid construction and usually in concrete or masonry.
RailCorp Engineering Manual — Structures Structures General TMC 300
PILE A vertical or inclined member driven or cast in the ground to support a trestle, pier, sill, abutment, wall or other superstructure. Includes:
- Batter pile: set at an angle to the vertical to resist sidesway;
- Planted pile: set in excavated hole then backfilled and compacted;
- Plumb pile: vertical pile;
- Potted pile: set in concrete below ground level;
- Pumping pile: a pile that is moving vertically in the ground under load;
- Spliced pile: two or more pile sections joined end-to-end by plates;
- Stump pile: pile section left in the ground after top removed.
PIPE Hollow longitudinal void near the centre of a timber member where the heartwood is usually situated.
PITTING An extremely localised form of corrosive attack that results in holes or hollows in metal. Pits can be isolated or so close together that they may look like a rough surface.
PORTAL An overhead structure consisting of side masts or columns joined at the top by a horizontal girder.
PROTECTION SCREEN
Screen installed on overbridges and footbridges to prevent accessibility to a safety screen and to restrict objects from falling or being thrown onto the track below.
R
REFUGE A ‘safe area’ provided along a bridge, retaining wall or in a tunnel.
ROCKFALL SHELTER A structure installed over and beside a rail track to prevent loose material from adjacent cuttings falling on to the rail line.
ROT Internal decay of a timber member caused by fungal attack.
REHABILITATION The actions necessary to restore a structure to its originally intended level of service in order to retain it in service for as long as possible. It is characterised by major repairs that are remedial in nature, are more costly and less frequent than those undertaken for maintenance.
REPAIR The actions necessary to increase the current level of serviceability, reliability and/or safety of a structure.
RUNNER Longitudinal member bolted to girders and transoms to hold transoms to correct spacing.
S
SAFE AREA A place where people and equipment will not be hit by a passing train.
SAFETY SCREEN Impenetrable barrier intended to prevent persons from contacting 1500 volt DC equipment and to protect the equipment from damage.
SAFETY WALKWAY An area along an underbridge where personnel can walk without falling through to the ground.
SCALING The gradual and continuous loss of surface mortar and or aggregate over irregular areas of concrete. It most frequently affects horizontal surfaces exposed to the weather or traffic, but could also be an indication of frost or salt attack.
SCREWING UP Maintenance process of tightening up body and other bolts to improve the load capacity of a timber bridge.
SERVICE CROSSING Structure carrying commercial product or utilities over or under a track and across the railway corridor.
RailCorp Engineering Manual — Structures Structures General TMC 300
SHAKES (IN TIMBER) Complete or partial separation, usually across the timber grain and due to causes other than shrinkage. Possible causes of shakes are due to felling of the tree, impact loading, stream forces or wind force.
SHEAR ZONE That area of a member near to a support, where a force acts through the member.
SHEETING Timber planks or steel panels, restraining the fill behind a wall type structure.
SILL Concrete or masonry footing supporting a trestle.
SOFFIT The underside of a bridge superstructure.
SPALLING Drummy or loose concrete, masonry or stone surfaces, which may have been initiated by corrosion of reinforcement or by heavy impact.
SPAN Deck of a bridge between adjacent substructure supports.
Also the distance between girder supports.
SPANDREL WALL A wall carried on the extrados (upper convex surface) of an arch, filling the space below the deck.
SPLIT Fissure in a timber member running parallel to the grain, from one face right through to the opposite face.
STATION PLATFORM Line-side structure built to provide public access to passenger trains.
STRAIN The lengthening or shortening of a member under load.
STRENGTHENING The form of enhancement which increases the load carrying capacity of a structure above the original design level. It is characterised by major repairs which are more costly and less frequent than maintenance.
STRESS Internal “pressure” in a member under load.
SUBSTRUCTURE The supports for a bridge deck including trestles, piers, abutments and foundations.
SUBWAY Underbridge passing over a pedestrian pathway.
SUPERSTRUCTURE The deck or “top part” of a bridge spanning between supports.
T
TENSION FACE The face of a member that is in tension. For beams it is usually the lower face and in particular near mid-span. For a cantilever or a continuous member it is the upper face over the supports.
TEREDO Marine borer which destroys timber in tidal areas.
TERMITE Insect (incorrectly called white ants) which attacks timber by eating the cells, causing strength loss.
THROUGH SPAN Span type where the main girders rise above track level.
TIP END SHEETING Sheeting behind extended timber girder ends of abutments.
TRANSOM Structural member (usually timber) laid across girders for attachment of rails on transom top spans.
TRANSOM TOP Underbridge where the track is directly fixed to the superstructure and metal ballast is not provided.
TRESTLE Intermediate support for bridge spans between abutments, usually constructed as a timber or steel frame.
TROUGHING Pipe in timber member starting at the top face.
TRUSS Girder made from two horizontal members (top and bottom chords), joined by vertical and diagonal members.
RailCorp Engineering Manual — Structures Structures General TMC 300
Appendix 5 Approved Bridge End Configurations Engineered Backfill
NEW FORMATION LEVEL (TOP OF CAPPING LAYER - SEE DRG No. SP521
GRADED BACKFILL
Class "GMB20" back fill to RTA MR Form 744 compacted as for embankment fill or equiv. To be
over the full width o
EMBANKMENT FILL Suitable fill (see ConstructionStandard) to be placed in 150mmlayers and compacted at optimum moisture content to 95% of the dry placed f
embankment.
Issued July 2010 2.2 UNCONTROLLED WHEN PRINTED Version
Figure 14
density as measured by themodified compaction test inaccordance with AS1289 E2-1-1977.
Geotextile, Bidum U34 or equiv.
Geotextile, Bidum U34 or equiv. only to be used if existing embankment has 10% or more of material passing a 5mm sieve, or if any silty or clay materials are present.
"Tensarplaced aovcentre li
Geotextile, Bidum U34 or equiv.
Geogrid SS2" to be s 2/4m sheets
erlapped 300mm on ne of track
Agricultural drain to grade down at 1:30 from centre line of track to each side of embankment.
Granular fill around tural drain agricul
30 degrees
1000
300 typ
RailCorp Engineering Manual — Structures Structures General TMC 300
STANDARD FLEXBEAM POST1800 LONGDRILL ON SITE TO SUIT
600 MIN.
VARIES TO SUITSITE CONDITIONS
FLEXBEAMGUARDRAIL
900
(TY
P)
600
25 MPaCONCRETEFOOTING
SECTIONN.T.S.
A-
FORMATION LEVEL
NOTE:BALLAST CAN BE EXCAVATED AND SUPPORTEDWITH STAR PICKETS AND TWO LAYERS 20mmPLYWOOD WHILE CONSTRUCTION OF FLEXBEAMGUARD RAIL TAKES PLACEFLEXBEAM MUST NOT ENCROACH ON STRUCTUREGAUGE.
Figure 15
Issued July 2010 2.2 UNCONTROLLED WHEN PRINTED Version
RailCorp Engineering Manual — Structures Structures General TMC 300
