Tuesday, April 19, 2005


Most of the publication I had encountered (with the most specific one from Gibb, 1999, Richard, 2004 and CIRIA, 1999) during my literature review had divided pre-assembly techniques into four category as follows:

1. Pre-assemble components and subassemblies
This type of pre-assembly is very commonand usually in the shape of component manufacture such as bricks, tiles, door furniture and window frame. This type of sub-assembly usually consist of items that are made in a factory and never considered for on-site production.

2. Volumetric pre-assembly (also called the Hybrid by Roger-Bruno Richard in his 2004 publication and Modularisation in CIRIA, 1999)
Volumetric pre-assembly are pre-assembled units that create usable space and are usually fully factory finished internally, installed within, or onto an independent structural frame. Plant rooms, toilet pods and shower rooms are included in this category. Examplease of materials used in volumetric pre-assembly units include dry-lined lightweight steel frames and pre-cast concrete.

3. Non-volumetric pre-assembly (also known as Meccano or Site Intensive Kit-of-Parts) on the other hand, consists of pre-assembled units which do not create usable space. This type of units can be in the form of skeletal (structural frames), planar (cladding and wall panels) or complex units (bridge units, services, etc). Material examples include steel, pre-cast concrete, timber, aluminium and advanced composites such as an integrated post and beam which can be opened vertically and horizontally.

4. Modular Building
A modular building comprises a number of volumetric units. There may be additional on-site works (such as an external brick skin or tiled roof) depending upon the specific project requirements. The modular units can be constructed in steel frames, stressed skin plywood, precast concrete or other various cladding amterials. Modular units are often use for high rise housing construction. It is either constructed as a self supporting structure or designed to rest on separate structural supports. Advantages include a better organised control of the entire building on site. However, modular unit construction does require a well-organised production line with relatively high capital investment, high shipping cost will also limit the marketing to a relatively small regions of a particular country only.

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