Building Technology 1 Project 2 Report

BUILDING TECHNOLOGY [ARC 3512]

1

Project 2 - Industrialized Building System OOI SHIN TZE 0302058 PANG KIAN MING 0309798 QUA YU XUAN 1001A75473 TAN HONG LOONG 0305483 TIOW TZE JINN 1101P13103 WONG CHEA YEE 0302420 WU HAO WEN 0302883

1.0 INTRODUCTION The Industrialized Building System (IBS) Roadmap 2003 - 2010 was published by the Construction Industry Development Board (CIDB) outlines several well-thought strategies 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 systematic approach and methadology in con- struction. The effort, started in 1998, is a strategic change in the construction industry.

It has been noticed that despite all the advantages adopting Besides the aim of gradually reducing the dependency on foreign labour and sav- ing exchange, IBS provides the opportunity for the play- ers in the construction industry to project a new image of the industry to be at par with other manufacturing-based industry such as the car and electronic industries. The adoption of IBS promises to elevate every level of the construction industry to new heights and image of professionalism.

of the new attributes that will be associated with the construction industry. With these outstanding features, plus attributessuch 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

still has a biased perception of IBS. It is admitted presently 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

and professional services.

Sunway Medical Centre, SUBANG JAYA

Subang Square.

Subang Jaya

1 Primary School, Kuala Lumpur

2.0 Case Study terms of larger clear distances between columns. As a result, the longer span The system can be used for buildings that offer a certain luxury of space such ings, commercial buildings and car parks.

the buildings that is constructed by the Industrialised Buildbuilt with The Precast Building-framed Build- ings System. 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

the num- ber of storeys could

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 assembly. These components are manufactured by industrial methods based on mass production in order to build a large number of buildings in a short time at low cost.

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

The main features of this construction 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 quality control and greater

3.1 Pre-cast Concrete Frame The precast concrete-framed building is one of the most popular forms of industrialised building systems preferred by architects and engineers. 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 systematically to produce similar components repeatedly. This building system offers quality materials, fast- track erection, robustness, durability and stability. The system is widely regarded as struc- turally sound and architecturally versatile.

Precast frames can be constructed using either linear elements or spatial beam-column sub-assemblages. Precase beam-column sub-assemblages can be placed away from the critical frame regions; however, linear elements are generally preferred sociated with forming, handling and erecting spatial elements.

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, rigid beam-column connections are used in some cases, when the continuity of longitudinal reinforcement through the beam-column joint needs to be ensured.

The components of a precase reinforced concrete

3.1.1 Pre-cast Concrete Columns Precast 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

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 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

3.1.3 Pre-cast Concrete Floor Slabs Precast hollow core slab or precase half slabs are types used depending on suitabilit low slabs are normally used for long span structure such spacious areas. While precast half slabs are used for short span structures ranging from

Large precast elements are normally supported on elastometic supporting pads in neoprene rubber to ensure a good distribution 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.

suitable for residential dwellings. 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 Wall Precast concrete wall is non-load bearing wall and is suitable for most types of buildings. It can be used for homes, townhouses, condominiums, apartments, hotels and schools and other. The wall panels are designed according to structural requirements for strength, safety and Openings for doors and windows are casted into walls at cilities such as electrical and telecommunication conduit and also casted in the panCapenters, electricians and plumbershave to make some

their normal practices.

Precast concrete wall manufactured in factory has smooth surfaces on both sides. Thus the textured surfaces are easily applied. Wall panels can be easily designed to undertake both structural requirements for strength and safety, as well as aesthetic and sound attenuation qualities are desired. Speedy construction and durability of panels.

3.1.5 Pre-cast Concrete Stairs Precast concrete stair slabs are usually designed to span longitudinally into beams. In monolithic construction, the stair slab can be designed with continuous 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 be designed as simple slab between supports.

In design, the dead load is calculated along the sloping based on the plan area. If the risers were to be covered 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 This will apply to precase stair slabs without landings.

The supporting nibs of the precase stair slab maybe constructed with either dry or wet connections (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 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 connections 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 Column

4.2 Connection Column to Column

The 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.

In all joints design, the connection must able to resist the applied structural forces. It should also be shown clearly wherever the joint functions as a pinned or moment connection.

Column-to-column splices are made other by bolting mechanical connectors anchored in the separate precast components or by the continuity of the reinforcement through a grouted joint.

(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

4.3 Connection Column to Pocket Foundation 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 non-shrink cement grout.

For grouted sleeve connection, precast concrete 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 concrete 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