The Industrialised Building System

The Industrialised Building System This chapter will explain in details and provide the literature review of Industrialised Building System (IBS). Besides that, it will also cover the literature review of building system. Usually, the contents of this chapter are including definitions of IBS, history of IBS in public housing, types of IBS, benefits and barriers of using IBS in public housing, classification of IBS, characteristic of IBS, IBS Roadmap 2003-2010 and IBS scoring system. 2.1 Definitions of IBS Until the present time there has been no single commonly-approved definition of IBS. IBS can be different industry players to define different things. However, there are difference resources to define the several definitions that reflected the concept of IBS which widely accepted by the construction industry. According to CIDB Malaysia (2001) defines IBS as a construction technique in which components are manufactured in a controlled environment (on or off site), transported, positioned and assembled into a structure with minimal additional site works. As such, components that are being prefabricated in a controlled environment on site are also considered as IBS. While there are numerous descriptions of the IBS concept by local researchers, all of the definitions stressed on prefabrication and mass production. In other definition by Warswaski (1999), the IBS can be defined in which all building such as walls, slabs, beams, columns and staircases are mass produced either in factory or at site factory under strict quality control and minimal wet site activities. Industrialisation process is an investment in equipment, facilities and technology with the objective of maximising production output, minimizing labour resource and improving quality while a building system is defined as a set 10 of interconnected element that joint together to enable the designated performance of a building. Based on Lessing et al (2005) explained IBS as an integrated manufacturing and construction process with well planned organization for efficient management, preparation and control over resources used, activities and results supported by the used of highly developed components. Rahman et al (2006) defined IBS as a construction system that is built using pre-fabricated components. The manufacturing of the components is systematically done using machine, formworks and other forms of mechanical equipment. The components are manufactured offsite and once completed will be delivered to construction sites for assembly and erection. 2.2 History of IBS in public housing IBS in Malaysia has began in early 1960s when Ministry of Housing and Local Government of Malaysia visited several European countries, at the same time evaluates their housing development program. (Thanoon et al, 2003). In the year 1964 and after their successful visit, the Government had launched pilot project on using IBS to speed up the delivery time and built affordable and quality houses. The first pilot project was constructed at Jalan Pekeliling in Kuala Lumpur and about 22.7 acres of land was dedicated to the project comprising four blocks of 4-storey flats and seven blocks of 17-storey flats and comprising total about 3,000 units of low cost flats for the low and median income group and 40 units of shop lots. This public housing project was undertaken by Gammon/ Larsen Nielsen and this project are using the Danish System of large panels in a industrialised prefabricated system. The construction for public housing project was complete from 1966 until 1968 (around total 27 months) including the time taken in the construction of the around RM 2.5 million casting yard at Jalan Damansara (Thanoon et al, 2003). In 1965, the Government of Malaysia launched a second project, is a three blocks of 18-storey flats and six blocks of 17-storey flats and comprising total about 3,699 units and 66 units of shop lots along at Jalan Rifle Range in Penang. The public housing project was awarded to Hochtief/ Chee Seng and this project are using French Estoit System (Din, 1984). This public housing project was complete within 27 months. If we are reference to the two pilot projects, a performance comparison between the IBS and the conventional system has been carried in terms of cost, productivity, quality, and time. According to the research, the first pilot project incurred 8.1% higher costs than a similar building and using conventional construction method, while the second pilot project was lower. In term of total construction speed, both of the public housing project required total 27 months to complete the whole project, inclusive of time required to set up the recasting factories. The total quality of building finishes was also found to be better than the using conventional construction method. Another earliest using IBS in public housing project was at Taman Tun Sardon in Penang. These using IBS in public housing project total all about 1,000 units of 5-storey walk up flat and this project are using IBS precast component and system. The IBS precast component and system in the housing project was designed to the low cost housing by British Research Establishment and especially for the low and median income group. According to the research of Construction Industry Development Board Malaysia (CIDB) 2006, almost at the same time at Edmonton in North London, there are using similar system was constructed and total amount about 20,000 BRECAST dwellings were constructed throughout UK from 1964 until 1974. The total all building design was very basic and quite simple and not considering the aspect of serviceability such as the local or user needs to have wet toilet and bathroom (Rahman and Omar, 2006). According to the CIDB (2006), many constructions in the following years using precast wall panel system. Low cost high rise residential building is one of the processes to observe that IBS was engage at first place in the construction to overcome the increasing demand for public housing needs. For all that, in the earlier stage was never sustained for the industrialisation of construction. Failure of early closed fabricated system made the industry afraid of changing their construction method. The information was based on the CIDB (2005), using IBS in construction were also found not be so suitable with Malaysia climate and social practices especially for the foreign systems that were introduced during the late 60s and 70s. Introduced than in the market were constantly being newer and better technologies. Based on CIDB (2005), identified to be more suitable to be used in our tropical climate is the wet joint systems and it was also better to using in the bathroom types which were relatively wetter than those in the Europe. Another about 1200 units of housing using prefabrication technology were is launched by the Penang State Government in 1978. After two years later, the Ministry of Defense to be build around 2800 units of living quarters and adopted large prefabricated panel construction system in Lumut Naval Base (Trikha and Ali, 2004). Increase the using of precast concrete system in high rise residential building during the 90s; this is because total demand for the new township has seen to increase. According to the research, Perbadaan Kemajuan Negari Selangor (PKNS) as a state Government development agency acquired precast concrete technology from Praton Haus International based on Germany to build low cost houses and high cost bungalows between 1981 and 1993 for the new townships in Selangor (Hassim et al, 2009 and National IBS Survey, 2003). It was recorded then; total around 52,000 housing units was constructed and using Praton Haus system. In this booming period of Malaysia construction 1994 to 1997, hybrid IBS application used in many national iconic landmarks such as Petronas Twin Towers (steel beams and steel decking for the floor system). In Malaysian construction industry, the use of IBS as a method of construction is evolving. Nowadays, more local manufacturers have established themselves in the market. Many had acquired enough knowledge through technology transfer to build up own capacity in IBS technologies and this research are base on PKNS Engineering, and Setia Precast and Global Globe. The current stage of IBS used in Malaysia housing projects can be classified into four categories such as large panel systems, steel frame, precast frame and formwork system. It was reported that at least 21 manufactures and suppliers of IBS are actively promoting their systems in Malaysia. IBS move to the next step of the development through the establishment of IBS Centre at Jalan Chan Sow Lin, Cheras in Kuala Lumpur. Using IBS in the construction is to improve the total performance and quality in construction, as well as to minimize the unskilled foreign labour in the construction market. 2.3 Classification of Building System There are four types of building system currently available in Malaysias building system classification and this are according to Badir Razali (1998). The building system can be namely as a Conventional Column-beam- slab frame system with timber and plywood; Cast in-situ system with steel or aluminium as formwork; the Composite building system and Prefabricated system and this four types of building system is shown as below. Each building system is represented by its respective construction method which is further characterised by its construction technology, functional and geometrical configuration. There from the four systems, are identified as IBS excluding conventional building system. Building System Conventional Column-beam- slab frame system with timber and plywood. Cast in-situ system with steel or aluminium as formwork. Composite building system Prefabricated system Table Form Tunnel Form Panel system Frame system Box system Flow Chart 1: Type of building system in Malaysia. 2.3.1 Conventional Construction Method Conventional construction method is defined as components of the building that are prefabricated on site through the processes of timber or plywood formwork installation, steel reinforcement, and cast in-situ. This construction method is mostly built of reinforced concrete frames for conventional building. Using the wooden formwork mainly is for the traditional construction method and need take some time to construct the formwork before concreting. This construction method is much more costly for construction which is need includes total labour requirement, raw material, transportation and very importance once is low speed of construction. 2.3.2 Cast In-Situ Construction Method This cast in-situ construction method is more suitable for a country where the unskilled labour is limited. There construction method is not a using heavy machinery or high technology involved. The system is technically and applicable to almost all types of building design. The formwork is used as a mould where wet concrete is poured into a temporary system. The temporary system also acts as a temporary support for the structures. The main objective of a cast in-situ construction method is to weed out and reduce the using traditional site-based trades like traditional timber formwork, brickwork, plastering and to reduce foreign workers requirement. A carefully planned in-situ work can maximise the productivity, speed and accuracy of prefabricated construction. Cast in-situ method uses lightweight prefabricated formwork made of steel or fibreglass or aluminium that is easily erected and dismantled. The steel reinforcement is placed within the formwork after finishes construct the formwork. After placing the reinforcement they are being erected and concrete is poured into the mould. When the concrete is set and according to the required strength, the moulds are dismantled. The workers can be easily trained to erect the moulds and set the steel reinforcement. These construction methods are required limited labour and it will reduce the total labour need. Its advantages over the conventional construction method in clude, low skill requirement, speedy construction, low building maintenance, durable structure and less construction cost. 2.3.3 Composite Construction Method The main objectives of composite construction method or call partially prefabricated are to improve quality of components, reduce construction cost, and shorten total all construction time. It is used to describe a manufacturing or production strategy that selectively uses some industrialising aspects, while avoiding or postponing the use of others. The concept of composite construction method is derived from the composite nature of full industrialisation. The prefabricated construction method is combined in such a manner that the features applied could be prominently demonstrated, especially composing various works such as temporary facilities, building frames, building finishes, and equipments. 2.3.4 Prefabricated Construction Method In this prefabricated construction method, all structural elements can be standardised are prefabricated in the factory. Usually, this construction method would involve the assembly of precast elements such as floor slabs, in-filled walls, bathrooms, staircases, and etc. into place for incorporation into the main units, columns and beams. This method of construction will increase the productivity of the industry and it will reduce the amount of site labour involved in building operations. Precast building systems can overall reduce the duration of a project if certain conditions are met. The last three construction methods (from the flow chart 1) are considered as a non conventional construction methods. These types of construction are specifically aimed at increasing performance of construction. Through the use of better construction machinery, equipment, technology and materials and it will increase the productivity and total quality of work. 2.4 Classification of IBS and Apply to Public Housing According to Badir et al. (1998), IBS can be classified according to several aspects:- Classification according to structural system. Classification according to material. Classification according to relative weight of components. 2.4.1 Classification According to Structural System According to Abraham Warszawski (1999), IBS can be classified according structural systematic aspects. IBS can be classifies into three categories as:- Frame System. Panel system. Boxes system. Figure 1, 2, and 3 shows the concept of the system as classified above. Figure 2: Panel System Figure 3: Box System Figure : Frame System 2.4.1.1 Frame System According to Badir (1998), linear and frame system is system that use main structure such as column and beam where columns and beams support all the building weight. The walls need to be light and easy to install and concrete panels are introduces as flooring element. 2.4.1.2 Panel System According to Badir (1998), in panel system, loads are distributed through large floor and wall panels where walls support the building weight. This system is applicable to buildings which functionally require a large number of walls such as apartment house, hotel and hospital. This system is not applicable to buildings with large spans or many stories. 2.4.1.3 Box System According to Badir (1998), the rectangular or three dimensional systems or boxes system include those systems that employ three dimensional modules or boxes for fabrication of habitable units that is capable of withstanding load from various directions due to their internal stability. 2.4.2 Classification According to Material 2.4.2.1 Timber The timber have a two types of prefabrication which is ready-cut plus shop fabrication of joints this mostly for the columns and beams and another is structural panels where there are only for walls and floors without columns and beams. 2.4.2.2 Brick and Block work Laying of brick or block work are carried out in a mass at factory and transported to site or on site construction. Besides the, building are under construction in the form of panel and then erected. 2.4.2.3 Steel Steel construction essentially contains factors of prefabrication which is one of the criteria of IBS. Elements are jointed by welding, riveting or bolting on site. The large proportion of the strength to the weight allows a long-span or high-rise building. 2.4.2.4 Reinforced Concrete There are two basic directions in development of reinforced concrete IBS component which is panelised components such as walls and floors and precast frame members such as columns and beams. The characteristic of reinforced concrete has high degree of availability, low material cost, durability, and fire resistance. Jointing at site is the key issue of this system. 2.4.3 Classification According to Relative Weight of Component The IBS components can be classified according to their relative weight as show in Table 1 below. Relative to weight of component should be used as a basic for building classification due to the factor of weight has significant impact on the transportability of components and has influence on the production method of the components and their erection method on site. No General System System Production Material 1 Frame System Light weight frame Wood, light gage metals Medium light weight frame Metal, reinforced plastics, laminated wood Heavy weight frame Heavy steel, concrete 2 Panel system Light and medium weight panel Wood frame, metal frame and composite material Heavy weight panel (factory produced) Concrete Heavy weight panel (tilt up-produced on site) Concrete 3 Box system (modules) Medium weight box (mobile) Wood frame, light gage metal, composite Medium weight box (sectional) Wood frame, light gage metal, composite Heavy weight box (factory produced) Concrete Heavy box (tunnel produced on site) Concrete Table 1: Building system classification according to relative weight of component. (Majzub, 1977) According to CIDB (2003), the IBS is a construction process that using techniques, products, components, or building system which involve prefabricated components and on-site installation. Base on the structure aspects of the system, IBS can be identified into five major groups:- Precast Concrete Framing, Panel and Box Systems Precast concrete elements are the most common type in this area. There are precast concrete for columns, beams, slabs, walls, lightweight precast concrete, and permanent concrete formwork. This all item are consider using precast method. Besides that, it is also consist of 3D components such as balconies, staircases, toilets, lift chamber, refuse chambers and etc. This precast method is more famous for the construction industry, especially for the public housing when construct using the IBS. Using this method can saving the total construction time if compare to the using conventional method. Figure 4: Precast concrete wall Steel Formwork Systems This is the system formwork which designed by manufacturer to replace a conventional timber formwork. It can be described as a mould which the wet concrete can be poured into the mould and form the required shape. These steel formworks systems are subjected to structural quality control and generally involve site casting. So, this type of IBS method is considered as the low level or least prefabrication in the construction industry. However, this steel formwork systems does offer fast construction and construction time saving and at the same time will provide high quality of finishes with less site labour and material requirement. These steel formwork systems will include table forms, tunnel forms, tilt-up systems, beam and columns moulding forms and permanent steel formworks like metal decks and etc. This steel formwork system also one of the famous system used by the contractor during the construction. Figure 5: Steel formwork system Steel Framing Systems These steel framing systems have always been the popular choice and used extensively in the fast track construction projects and this system commonly used with precast concrete slabs, steel columns and beams. Current stage of development in this type of IBS includes the increased usage of light steel trusses. It is consisting of cost-effective profiled cold-formed channels and steel portal frame systems as alternatives to the heavier traditional hot-rolled sections. Nowadays, this method are more useful for the housing project, especially apply for the steel roof trusses (show as below figure 6). This is because the timber roof trusses need the labour to take some time to construct it and lastly need the anti-termite for the timber roof trusses. Figure 6: Steel roof trusses Prefabricated Timber Framing Systems. These prefabricated timber framing systems is using the timber in the construction industry for construct building. Usually the timber framing system are consists of timber building frames and timber roof trusses (show as below figure 7). While the steel framing systems have been the more popular choice on construction industry, but the timber roof truss system also have its own market where it is offering interesting designs from simple dwelling units to buildings requiring high aesthetical values such as chalets for resorts. This prefabricated timber framing system we can see in the traditional building. Figure 7: Prefabricated timber framing system for double storey house Block Work Systems. By using this effective alternative system, the tedious and time-consuming traditional brick laying tasks are greatly simplified. The construction method of using conventional bricks has been revolutionized by the development and usage of interlocking concrete masonry units (CMU) and lightweight concrete blocks and etc. This is one of the more useful methods to construct the low cost public housing project. Figure 8: Lightweight concrete blocks are used for wall construction Characteristics of IBS for public housing According to Warszawski (1999), the main features of an IBS are as follows:- As many of the building elements are prefabricated off site, at a central facility, where specialized equipment and organization can be established for this purpose. The various building works are incorporated into large prefabricated assemblies with minimum erection, jointing and finishing work onsite. Materials and component handling onsite is extensively mechanized; in concrete work, large standard steel forms, ready-mixed concrete, and concrete pumps are used. Design, production, and erection onsite are strongly interrelated. They must be viewed therefore as parts of an integrated process which has to be planned and coordinated accordingly. According to CIDB (2001), IBS has its own characteristics which are differ itself from conventional method. There characteristics of IBS are as follows:- Industrial production of components though prefabrication; or highly mechanized in situ processes. Reduced labour during prefabrication of components and site works. Modern design and manufacturing methods which has the involvement of Computer Aided Design (CAD) and Computer Aided Manufacturing (CAM). Systematic Quality Control such as ISO 9000 principles. Open Building concept where it is permitting hybrid applications, adaptable to standardization and Modular Coordination (MC). Advantages of IBS for public housing There are many advantages of implementing IBS. According to CIDB (2003), compares to conventional construction method. Following are brief descriptions on a number of advantages where using IBS for the public housing:- Advantages Description Less total construction time. Using IBS will making the construction process faster. Because casting of precast element at factory and foundation work at site can occur simultaneously and work at site is only the erection of IBS components. So, the project can complete much earlier that using conventional method and handover to the owners. Cost saving. Faster to the turnover of working capital and also save in the lifecycle costs of the finished buildings. The formwork of IBS components are made of steel, aluminums or other materials that allows for repetitive use and this leads to considerable cost savings. Using IBS will reduce the construction wastage and increasing the cost saving. Saving in labour. Because the IBS components are produced in factory and higher degree of using machine so the use of labour will be reduced and lead to saving in labour cost. According to Abraham Warszawski (1999), the labour savings in prefabricated elements may amount to about 80% of their conventional requirement. So, will reduced the total foreign workers need in the construction industry. Less labour at site. Using IBS will reduce the construction process at site and consequently reduce the number of labour required at site. Using the IBS will saving of the labour in the masonry, plastering, formwork, tiling and pipe laying such as electrical and water supply at site. Optimised use of materials. Using machine during the production of IBS components lead to higher degree of precision and accuracy in the production and consequently reduce material wastage. So, the wastage at site will be reduced if using the IBS. High quality and better finishes. Quality control is an ever-increasing requirement in all construction. Due to the careful selection of materials and use advanced technology, so the IBS components will provide higher quality and better finishes. Better quality control since production in factory is under sheltered environment. Better quality will reduce the maintenance expenses because prefabricated components require less repair and preventive maintenance. Construction operation less affected by weather. The effects of weather on construction operation are less due to the fabrication of IBS components is done in factory while at site is only erection of the components. Faster project completion due to rapid all weather construction. Flexibility. Different systems may produce their own unique prefabrication construction methods. IBS will provide more flexibility in the design of precast element. Increase site safety and neatness. This method will lead to the neater site condition and increase safety. Using IBS components leads to less construction process especially for the wet work at site. Disadvantages of IBS for public housing Although there are a lot of advantages of IBS, however there are limitations for this system to be use too. Nothing in this world is perfect, so as using IBS. Disadvantages of IBS are as follows:- Advantages Description High initial capital cost. The initial capital cost of IBS is usually higher that conventional method. The initial cost is including the cost of constructing the factory, casting beds and support machinery. This method only can be achieved when undertaking large demand for public is housing projects. Problem of joints. These method are very sensitive to the errors and sloppy work. This joint problem will be the water leakage and is often the major problem in building constructed where using IBS. This problem is clearer in Malaysia where raining occur rapidly throughout the year. Sophisticated plants and skilled operators. The prefabrication system relies heavily on sophisticated plants, which have to be well coordinated and maintained by skilled operators. Breakdown in any one section would hold-up the entire production line. Site accessibility. Site accessibility is one of the most important factors of the implementation of IBS. IBS requires adequate site accessibility to transport IBS components from factory to the site. According to Abraham Warszawski (1999), the transportations cost of prefabricated elements from plant to their construction site, amount to 3% to 5% of their total cost for distances not exceeding 50km to 100km. Large working area. Building construction using IBS requires a large working area for the factory, trailers, tower-cranes and storage for the IBS components. Most construction sites especially in cities are often congested and unable to provide the area required. Hence, prefabrication is at disadvantage when asked to complete for work at locations far from the fabrication yard. Table 2 shows as the relative advantages and disadvantages of industrialization under various conditions. Table 2: Relative advantages and disadvantage of industrialization under various conditions. IBS Roadmap 2003-2010 Prefabricated construction in Malaysia started way back almost fourth years ago with the completion of the Tunku Abdul Rahman Public Housing Estate or commonly known as the Pekeliling Flats. No proper plan was formulated by the government for the industrialisation of construction and until the inception of the IBS Roadmap 2003-2010. This is a master plan to facilitate the transformation the Malaysian construction sector was formulated with inputs from industry and endorsed by the Cabinet back in October 2003. Known as the Industrialised Building System (IBS) Roadmap 2003-2010, the master plan is based on the 5-M Strategy (Manpower, Materials-Components-Machines, Management-Processes-Methods, Monetary economic and financial and Marketing promotion) with the target of having an industrialised construction industry as well as achieving Open Building by the year 2010. The transformation of the construction sector is crucial in ensuring the successful achievement of Vision 2020. The objectives of IBS Roadmaps 2003-2010 are:- To reduce the percentages of foreign workers from the current stage is 75% to 55% in 2005, 25% for 2007 and 15% for 2009. Increasing the percentages of using IBS for the Government Building Project from the 30% to 50% for 2006 and 70% for 2008. To increasing the quality, productivity, safety and competitiveness in the construction sector. To reduce the total percentages of foreign workers especially involved in wet trades. Using modular co-ordination (MC) based on MS 1064 through Undang-undang Kecil Bangunan Seragam (UKB