BUILDING TECHNOLOGY 1 [ARC 3512]

Project 2 - Industrialized Building System

OOI SHIN TZE 0302058PANG KIAN MING 0309798QUA YU XUAN 1001A75473TAN HONG LOONG 0305483

TIOW TZE JINN 1101P13103WONG CHEA YEE 0302420WU HAO WEN 0302883

1.0 INTRODUCTION

The Industrialized Building System (IBS) Roadmap 2003 - 2010 was published by the Construction Industry Devel-opment Board (CIDB) outlines several well-thought strate-gies and aggressive steps to promote the use of IBS in Malaysia. The government is taking the leading role in persuading the construction industry to adopt a more sys- tematic approach and meth-adology in con- struction. The effort, started in 1998, is a strategic change in the con-struction industry.

Besides the aim of gradually reducing the dependency on foreign labour and sav- ing WKH� FRXQWU\·V� ORVV� LQ� IRUHLJQ�exchange, IBS provides the opportunity for the play- ers in the construction industry to project a new image of the in-dustry to be at par with other manufacturing-based industry such as the car and electron-ic industries. The adoption of IBS promises to elevate every level of the construction in-dustry to new heights and im-age of professionalism.

,I�,%6�LV�DGRSWHG��HIÀFLHQW��FOHDQ��VDIH�DQG�LQQRYDWLYH�DUH�VRPH�of the new attributes that will be associated with the construc-tion industry. With these outstanding features, plus attributes-such as professionally managed and handled, workers with relevant skills, proper coordination and manage- ment as well quality will inevtably make IBS an excellent option for those involved in the industry to become global industry players in WKH�LQWHUQDWLRQ��DO�DUHQD�WKDW�GHPDQGV�KLJK�TXDOLW\��HIÀFLHQF\�and professional services.

It has been noticed that despite all the advantages adopting ,%6��D�VLJQLÀFDQW�SRUWLRQ�RI� WKH�FRQVWUXFWLRQ� LQGXVWU\�SODWHUV�still has a biased perception of IBS. It is admitted presently WKDW�VZLWFKLQJ�R�,%6�ZRXOG�QRW�JXDUDQWHH�VLJQLÀFDQW�VDY��LQJV�in the cost constructed. However, IBS has demonstrated that the savings in the construction time is able to compensate the high construction cost incurred.

Examples

IKEA, MUTIARA DAMANSARA The Curve, MUTIARA DAMANSARA

Sunway Medical Centre, SUBANG JAYA

%ULFNV¿HOG�1 Primary School, Kuala Lumpur

Subang Square. Subang Jaya

2.0 Case Study7KH�,%6�V\VWHP�LV�VXLWDEOH�IRU�EXLOGLQJV�WKDW�QHHG�D�KLJK�GHJUHH�RI�ÁH[LELOLW\�LQ�terms of larger clear distances between columns. As a result, the longer span JLYH�ELJJHU�RSHQ�VSDFHV�DQG�D�JUHDWHU�IUHHGRP�IRU�GHVLJQLQJ�WKH�ÁRRU�DUHDV��The system can be used for buildings that offer a certain luxury of space such DV�LQ�WKH�FDVH�RI�RIÀFH�EXLOGLQJV��VFKRRO�EXLOGLQJV��KRVSLWDOV��XQLYHUVLW\�EXLOG-ings, commercial buildings and car parks.

7D\ORU·V� 8QLYHUVLW\� LV� RQH� RI�the buildings that is construct-ed by the Industrialised Build-LQJ�6\VWHP��,%6���7D\ORU·V�ZDV�built with The Precast Build-ing-framed Build- ings Sys-tem. This system is employed for low-rise to medium-rise buildings. If this system is used for commercial buildings such as hypermarkets or car parks, the number of storeys is generally not more than ÀYH�� +RZHYHU�� LI� WKH� V\VWHP�LV� XVHG� IRU� RIÀFH� EXLOGLQJV��the num- ber of storeys could UHDFK�XS�WR�ÀIWHHQ�

7D\ORU·V� 8QLYHUVLW\� XVHG� SUH-cast concrete frame system to save on cost and time.

3.0 Precast Concrete Structures

The concept of precase (Also known as “prefabricated”) construction includes those buildings, where the majority of structural components are standardize and produced in plants in a location away from the building, and then transported to the site for as-sembly. These components are manufactured by indus-trial methods based on mass production in order to build a large number of buildings in a short time at low cost.

The main features of this con-struction process are as follows: - The division and specialization of the human workforce- The use of tools, machinery and, other equipment, usually automated, in the production of standard, inter changeable parts and products.- Compared to site-cast concrete, precast concrete erection is faster and less affected by adverse weather conditions. - Plant casting allows ��LQFUHDVHG�HIÀFLHQF\��KLJK� quality control and greater ��FRQWURO�RQ�ÀQLVKHV��

This type of construction requires a restructuring of entire conventional construction process to enable interaction between design phase and produc-tion planning in order to improve and speed up construction

The precast concrete-framed building is one of the most popular forms of industrial- ised building systems pre-ferred by architects and engi-neers. The framed buildings consist of slab. beam and column components that are fabricated or “manufactured” off-site us- ing machines and formworks. The fabrica- tion process is carried out sys-tematically to produce similar components repeatedly. This building system offers quality materials, fast- track erection, robustness, durability and sta- bility. The system is widely re-garded as struc- turally sound and architecturally versatile.

3.1 Pre-cast Concrete Frame

Precast frames can be con-structed using either linear elements or spatial beam-col-umn sub-assemblages. Pre-case beam-column sub-as-semblages can be placed away from the critical frame regions; however, linear ele-ments are generally preferred EHFDXVH�RI�WKH�GLIÀFXOWLHV�DV-sociated with forming, han-dling and erecting spatial el-ements.

The use of linear elements generally means placing the connecting faces at the beam-column junctions. The beams can be seated on corbels at the column, for ease of construction and to aid shear transger from the beam to the column. The beam-column joints accomplished in this way are hinged. However, rig-id beam-column connections are used in some cas-es, when the continuity of longitudinal reinforcement through the beam-column joint needs to be ensured. The components of a precase reinforced concrete IUDPH�DUH�VKRZQ�LQ�WKH�ÀJXUHV�

3.1.1 Pre-cast Concrete ColumnsPrecast columns are manufactured in a variety of sizes, shapes and lengths. The concrete surface is smooth and the edges are chamfered. Columns generally require a minimum cross-sectional dimension of 300 x 300 mm, not only for reasons of manipulation but also to accomodate the column-beam connections. The 300 mm dimension provides a two-hour ÀUH�UHVLVWDQFH�PDNLQJ�LW�VXLWDEOH�IRU�D�ZLGH�UDQJH�RI�EXLOGLQJV��

Columns with a maximum length of 20m to 24m can be manufactured and erected in one piece, i.e. without splicing, although a common practice is to work also with single storey columns.

Precast Columns may be provided with single or multiple FRUEHOV� WR�VXSSRUW� ÁRRU�RU� URRI�EHDPV��JLUGHUV� IRU�RYHU-bead cranes, etc. The corbels are either completely under the beam or within the overall depth of it. This may occur, for example, where it is unacceptable for the connection to project below ceilings or into service zones. Standard dimensions for normal corbels are given in the table. The indicated values for the allowable support load “N” are characteristics values without partial safety margins.

3.1.2 Pre-cast Concrete Beams

Large precast elements are normally supported on elastometic supporting pads in neoprene rubber to ensure a good distribu-tion of the stresses over the contact area. The effective bearing length is determined by the ultimate bearing stress in both the abutting components and the bearing pad, plus allowances for tolerances and spalling risk at the edges.

The pads should be placed at some destance from the support edge load transfer at the edge may results in damage. The pad should allow for the beam and the support edge is avoided.

3.1.3 Pre-cast Concrete Floor Slabs

Precast hollow core slab or precase half slabs are types RI� ÁRRULQJ� V\VWHP�ZKLFK� DUH�used depending on suitabilit RI�ÁRRU�VWUXFWXUH��3UHFDVW�KRO-low slabs are normally used for long span structure such DV�RIÀFH�EXLOGLQJV� WR�SURYLGH�spacious areas. While precast half slabs are used for short span structures ranging from WZR� WR� ÀYH�PHWHUV�ZKLFK� DUH�suitable for residential dwell-ings. Since precast slabs are manufactured individually, each slab is joined to each other to form a diaphragm and is strenghten with cast in-situ structural concrete topping of thickness ranges between 50mm to 75mm

Long Span Precast Hollow Floor Slab

Long Span Precast Hollow Floor Slab

Short Span Precast Hollow Floor Slab

3.1.4 Pre-cast Concrete WallPrecast concrete wall is non-load bearing wall and is suitable for most types of buildings. It can be used for homes, townhouses, condo-miniums, apartments, hotels and schools and other. The wall panels are designed ac-cording to structural require-ments for strength, safety and RWKHU� IHDWXUHV� DV� VSHFLÀHG��Openings for doors and win-dows are casted into walls at PDQXIDFWXULQJ�SODQW��8WLOLW\�ID-cilities such as electrical and telecommunication conduit RU� ER[HV� DUH� ÁXVKPRXQWHG�and also casted in the pan-HOV�DW�WKH�VSHFLÀHG�ORFDWLRQV��Capenters, electricians and plumbershave to make some VOLJKW� DGMXVWPHQWV� WR� À[� WKH�XWLOLW\� ÀWWLQJV� DFFRUGLQJO\� DV�their normal practices.

Precast concrete wall manufactured in facto-ry has smooth surfaces on both sides. Thus the ZDOO� ÀQLVKHG� VXFK� DV� SDLQWLQJ� RU� RWKHU� GHVLUHG�textured surfaces are easily applied. Wall panels can be easily designed to undertake both struc-tural requirements for strength and safety, as well as aesthetic and sound attenuation qualities are desired. Speedy construction and durability of ÀQLVKHG�VWUXFWXUHV�DUH�KDOOPDUNV�RI�SUHFDVW��ZDOO�panels.

3.1.5 Pre-cast Concrete Stairs

Precast concrete stair slabs are usually designed to span longitudinally into WKH� ODQGLQJV�DW� ULJKW� DQJOHV� WR� WKH� VWDLU� ÁLJKWV� RU� VSDQ�EHWZHHQ� VXSSRUWLQJ�beams. In monolithic construction, the stair slab can be designed with contin-uous end restraints over the supports. But in instances where staircases are precast, the construction is generally carried out after the main structure, with pockets or recesses left in the supporting slabs or beams to receive the stairs ÁLJKWV��:LWK�QR�DSSUHFLDEOH�HQG�UHVWUDLQWV��D�SUHFDVW�VWDLU�VODE�FRXOG�WKHUHIRUH�be designed as simple slab between supports.

In design, the dead load is calculated along the sloping OHQJWKV�RI�WKH�VWDLUV�EXW�WKH�OLYH�DQG�ÀQLVKLQJ�ORDGV�DUH�based on the plan area. If the risers were to be covered ZLWK�ÀQLVKHV��DGGLWLRQDO�ORDGV�ZRXOG�KDYH�WR�EH�DGGHG�LQ�the design. The effective span is measured horizontally between the centres of the supports of the actual horizontal length of the precase stair slab where dry connections are used at the supports. The thickness of the waist is taken as the slab thickness.

The basic span-effective depth ratio maybe increased by 15% to 23 (= 20 x 1.15) if the VWDLU�ÁLJKW�RFFXSLHV�DW�OHDVW�����RI�WKH�VSDQ��This will apply to precase stair slabs without landings.

The supporting nibs of the precase stair slab maybe constructed with either dry or wet con-nections (Extended bearings). The design of reinforcement of the nibs can be based on:- Simple bending- Strut and tie force model- Shear friction

4.0 Precast Concrete Structures Connections%HDPV�DQG�FROXPQV�DUH�FRQQHFWHG�WR�IRUP�DQ�LQWHJUDWHG�IUDPH�V\VWHP�EHIRUH�WKH�ÁRRU�VODEV�DUH�SODFHG��+HQFH�structural connectors are required to connect all the structural components of beams, columns and slabs. The most important connections are beams to column, column to column and column to base and these connec-tions are either structurally pinned or rigid. The complete precast frame must be designed to comply with the required strength, stiffness, ductility and reliability

4.1 Connection Beam to ColumnThe simplest connection of beam to column is to place beam on top of column. However, for two or three storey building, it is suitable to use column with corbel or nib support.

(A) Column to beam connection with corbel

(B) Column to beam connection with nib support

(C) Column to rectangular beam connection

(D) Column to edge beam connection

4.2 Connection Column to Column

In all joints design, the connection must able to resist the applied struc-tural forces. It should also be shown clearly wherever the joint func-tions as a pinned or moment connection.Column-to-column splices are made other by bolting mechanical con-nectors anchored in the separate precast components or by the conti-nuity of the reinforcement through a grouted joint.

4.3 Connection Column to Pocket Foundation

3UHFDVW�FROXPQV�DUH�À[HG�WR� WKH� IRXQGDWLRQV�ZLWK�SRFNHWV��SURMHFWLQJ�UHLQIRUFLQJ�EDUV�RU�KROGLQJ�GRZQ�EROWV��7KH�ÀUVW�VROXWLRQ�LV�PDLQO\�XVHG�IRU�IRXQGDWLRQV�RQ�JRRG�VRLO��WKH�VHF-ond and third in the case of foundation piles.

Pocket foundation is the most economical connection of column to foundation for large concrete pad footings. Precast concrete column is inserted into pocket formed in IRRWLQJ�DQG�WKH�JDS�LQ�EHWZHHQ�LV�ÀOOHG�ZLWK�non-shrink cement grout.

For grouted sleeve connection, precast con-crete column is manufactured with sleeves. It is then placed on to foundation hich has projecting rebars. The rebars are inserted accurately into the sleeves of precast con-crete column. It is then strengthened and secured with non-shrink cement grout as shown in the diagram beside.

4.4 Precast Hollow Core Slab Support Connections

4.5 Connection Precast Wall to Hollow Core Slab

4.6 Precast Stairs Support Connections

4.7 Nib Reinforcement Details

Edge Beam

Rectangular Beam