The University of Sheffield

Department of Civil and Structural Engineering

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Bridge Engineering Researchat

The University of Sheffield

Dr Paul Reynolds

Vibration Engineering Section

http://vibration.shef.ac.uk/

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

The Department of Civil and Structural Engineering

• 27 academics – 11 in structures• Particular research strengths in

– structures (dynamics, NFR, fire, computational mechanics)

– concrete materials (durability, sustainability)– groundwater protection and restoration

• Areas of interest specific to bridge engineering– use of FRP composites in bridges– masonry arch bridges and parapets– vibration serviceability of footbridges

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

The Centre for Cement and Concrete (CCC)

• Established 1993• Director: Professor Peter Waldron• Academic Members: 17• Researchers: 48• Manager: Dr Kypros Pilakoutas

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Vibration Engineering Section

• VES was established by Prof. Peter Waldron in 1993

• Currently managed by Drs Paul Reynolds and Aleksandar Pavic

• Expertise in vibration serviceability of civil engineering structures, including:– floors– sports stadia– footbridges

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

London Millennium Bridge

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Vibration Serviceability of Footbridges

• VES has been engaged in footbridge VS research since 1993

• London Millennium Bridge raised awareness of the problems– SLE is a relatively uncommon particular

problem that needs to be fully understood– there are much more common issues that

require further research

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Areas of Current Uncertainty

Source Path Receiver

Pedestrian Excitation• individual pedestrians• small groups• large crowds

Vandal Loading

Non-Pedestrian Excitation

Modelling• inclusion of non- structural components• boundary conditions• simplified methods?

Designing in Damping• the future?

Acceptable Levels ofVibration• stationary vs. moving

Levels of Vibration tocause “lock-in”• horizontal• vertical

Synchronous Lateral Excitation (SLE)

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

VES Approach to VS

Analytical Modelling Dynamic Testing

Finite Element Analysis• (usually ANSYS)

MATLAB simulations• time domain simulations using convolution methods• Monte-Carlo simulations to examine statistical models of human excitation

Modal Testing• using shaker excitation• using natural/ambient excitation

Vibration ResponseMeasurements• controlled pedestrians• vandal loading

Remote Monitoring

FE model correlation• MAC/COMAC etc.

FE model updating• FEMtools software

LEARNING HOW TOMODEL BETTER

FOOTBRIDGEDYNAMICS

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Shaker Modal Testing

Aberfeldy Footbridge – Scotland

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Shaker Modal Testing

InputLinear

SystemOutput

controlled shaker excitation acceleration responsemeasurement

natural frequenciesmode shapesmodal damping ratiosmodal masses

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Shaker Modal Testing

• Lateral Modes

f = 0.98 Hzζ = 1.0 %

f = 5.72 Hzζ = 1.7 %

f = 2.73 Hzζ = 1.2 %

f = 8.50 Hzζ = 2.7 %

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Shaker Modal Testing

• Vertical Modes

f = 1.52 Hzζ = 0.4 %

f = 2.49 Hzζ = 0.7 %

f = 1.86 Hzζ = 0.70 %

f = 3.01 Hzζ = 0.8 %

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Shaker Modal Testing

• Torsional Modes

f = 3.48 Hzζ = 5.5 %

f = 5.10 Hzζ = 4.2 %

f = 4.29 Hzζ = 3.2 %

f = 6.05 Hzζ = 3.3 %

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Shaker Modal Testing of London Millennium Bridge

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Ambient Vibration Testing

Royal Victoria Dock Bridge – London

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Ambient Vibration Testing

f = 0.39 Hzζ = 1.7 %

f = 1.27 Hzζ = 0.8 %

f = 2.58 Hzζ = 0.4 %

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Pedestrian Response Tests

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Areas of Current Uncertainty

Source Path Receiver

Pedestrian Excitation• individual pedestrians• small groups• large crowds

Vandal Loading

Non-Pedestrian Excitation

Modelling• inclusion of non- structural components• boundary conditions• simplified methods?

Designing in Damping• the future?

Acceptable Levels ofVibration• stationary vs. moving

Levels of Vibration tocause “lock-in”• horizontal• vertical

Synchronous Lateral Excitation (SLE)

Areas for Future Research

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Durability High strength

Low weight

Driving Interests for FRP

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

ChalgroveFootbridge

(1995/96)

Eurocrete – Case Studies

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Oslo Footbridge(1996/97)

Eurocrete – Case Studies

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

US Department of Transportation

Sierrita de la Cruz Creek Bridge

(2000)

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Flexure and Cracking

Punching Shear

Shear

Bond

Design Philosophy Plate Bonding

Column Confinement

RCEBR

Shear Strengthening

Research on FRP at Sheffield

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

fib Task Group 9.3http://allserv.rug.ac.be/~smatthys/fibTG9.3 Eurocrete Project (94-97)

EU TMR ConFibreCreteNetwork (97-02)

http://www.shef.ac.uk/~tmrnet

CurvedNFRCRAFT Eureka (03-05)

http://www.curvednfr.com

Sheffield Involvement in FRP Research

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Required Bridge Research on FRP

• Demonstration/monitoring projects

• Design Guidelines

• Whole-life costing studies

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Permanent Formwork Systems

Steel deckingCorrosion

Fire protectionConstant thicknessOne way spanning

Need additional finishes

Pre-cast concreteHeavy

GRCLow stiffness (tensile

stress↓)Small (1~2 m span)

panels

Omni-plank typeCrack in tension zone

during casting

Permanent Formwork

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

DrainageDrainage

TunnelsTunnels

ArchitecturalArchitectural

BridgesBridges

Light self-weight

Easy to create complicated

shapes

Good Durability of the cover

Fast to install

Corrosion protection to the

steel reinforcement

GRC Permanent Formwork

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Bridge Permanent Formwork

• Combination of new materials

• Development of integrated permanent formwork solutions

• Solve the problem of formwork connections

• Case studies

• Design guidelines

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Tyre Recycling

Shredded Bending Tests

Pyrolysed

Research Work

Bond Tests

Cube Tests Design Rules

Bridge Applications:• Foundations• Decks

http://www.shef.ac.uk/tyre-recycling

Steel Fibres Recycled from Waste Tyres

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Masonry parapet research

• EPSRC project (also involving Universities of Liverpool & Teesside) recently completed

• Concerned with: (i) fundamental behaviour; (ii) developing reinforcement strategies

• Key findings:– Typically failure via large-panel

formation (resistance then due to inertia & base friction)

– But very weakly mortared walls fail in loose block failure modes

– Diagonal reinforcement effective (even when mortar bond v. weak)

– Analysis tools now developed which can simulate behaviour in many cases

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Masonry parapet research:potential follow-on work

• Do bridge owners wish to support follow-on developments?1. Transformation of mechanism analysis research software into usable tool

for practitioners

2. Update CSS guidance note and BS6779-4 to reflect our much improved understanding of how masonry parapet walls resist vehicle impacts

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Masonry parapet research:mechanism analysis software

• Method (published in Int. J. Impact Eng, 2002) identifies critical mechanism from a library of possible ones:

• Quick & easy to investigate the influence of different parameters

x

x

5

5

C

A

DE

B

B

A

D

A

B

x2

B

AD

x4

A

DE

B

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Masonry parapet research: update to design codes

• Original numerical modelling work which underpinned CSS document and BS6779-4 has now been significantly improved upon

• Also potential for inclusion of more guidance on reinforcement strategies

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

•Sophisticated Sophisticated masonry block masonry block modelling modelling capabilitycapability

•Simple uncoupled Simple uncoupled backfill interaction backfill interaction model model

1funded to date by Network Rail

RINGRING11: : Masonry arch bridge analysis Masonry arch bridge analysis softwaresoftware

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Lateral earth pressures based on modified Rankine theoryLateral earth pressures based on modified Rankine theory

h

passive

h=KP v

Example modified distributions

Current backfill interaction models

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Key Project Aims

• Development of RING to include fully coupled modelling of soil and masonry elements

• Develop optimised field investigation techniques for backfill characterisation

• Calibrate on field, model and laboratory tests: load and kinematic data

Work sponsored by Essex County Council in collaboration with Mouchel Essex

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Image analysis provides soil displacement vectors

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

Additional aims:

• Incorporate current geotechnical design code principles into assessment methodology

• Develop soil and masonry reinforcement modelling capability in RING with automatic optimisation (sponsored by EPSRC)

Presentation to the Joint Bridge Researchers’ and Owners’ Forum, Cambridge University, 27 October 2003.

For more information …

• Dr Paul Reynolds– Tel: 0114 222 5074– p.reynolds@sheffield.ac.uk

• Web sites:– http://vibration.shef.ac.uk/– http://www.shef.ac.uk/civil/

• This presentation will be posted at:– http://vibration.shef.ac.uk/presentations/bridgeforum/