Although the application of precast concrete system to multi-storey apartment buildings can be traced back to the construction of apartment building at Sarijadi, Bandung in 1979, significant research on precast concrete building was initiated by founding an association, namely Indonesian Association of Precast and Prestressed Concrete Engineers in 1999. To date, about 22 precast structural systems have been designed, patented and applied nationwide. See Table 1 for explanation. In 2007, Department of Public Works, the Republic of Indonesia has adopted several standards and manuals in the design, testing, fabrications, and handling of precast concrete structural systems.
Minimum requirements a precast concrete system has to be fulfilled in order to be applicable in construction field are, among others, the design and patenting, laboratory testing, and mock-up. A seminar will be conducted so as to determine the acceptability of the newly developed system, followed by the issuance of a certificate sanctioned by the Department of Public Works. Concerning the laboratory testing, several aspects pertaining to the newly structural precast systems, are investigated, i.e., the strength, failure mechanism, load-displacement hysteretic loop, and some other factors such load reduction factor R [6,8,9]. In the laboratory testing, earthquake
3. NORMS, STANDARDS, PROCEDURES AND MANUALS
excitation load should be considered, due to the fact that almost large cities in Indonesia are located in medium up to strong earthquake motion Nowadays, no formal norms, standards, specifications nor manuals concerning precast concrete available for practices in Indonesia. For the time being, practices in the design and field applications are carried out referring to local and foreign standards such as Indonesian concrete code SNI 03-2847-2002, PCI, ACI, AASHTO or UBC codes [1,2,3,4,5,7,10]. Today, National Bureau for Standard (Badan Standard Nasional, BSN) and Research and Development Bureau (Badan Penelitian dan Pengembangan, Balitbang) Department of Public Works undergo programs to establish norms, standards, specifications and manuals concerning precast concrete practices.
4. DESIGN OF MULTI-STOREY PRECAST CONCRETE STRUCTURAL SYSTEMS
Generally, following engineering practices, design of a multi-storey low-cost apartment is carried out by considering soil condition, dead and live loading, earthquake zoning of the location of construction to determine earthquake excitation load. As far as earthquake loading is concerned, load reduction factors for light, moderate and strong earthquake are taken as R = 5.5, 8.5 and 8.5 respectively [2].
To minimize shape effect, floor plant is managed to be more symmetrical, with aspect ratio not to exceed 3.0.
Should ground floor is construed to be an open storey, extra lateral bracing should be provided.
5. APPLICATIONS OF PRECAST CONCRETE SYSTEMS IN INDONESIA
As already mentioned before, the applications of precast concrete structural systems were initiated in 1979 in the construction of Sarijadi low-cost medium rise apartment in Bandung, West Java. The use of waffle-crete system (American patent) in the project of Cengkareng apartment in 1995, as shown in Figure 4 and 5, has ever since ignited the motivation of Indonesian engineers to design and discover several precast concrete structural
systems already tabulated in Table 1. It should be brought to mind that with the total population of Indonesia about 250 millions, and an estimated 1.0 percent rate of annual birth and an assumption of 4 persons per family, that has ever been accruing annually.
Works is held responsible for the restoration of slum settlement region, while State Ministry of Public Housing is held responsible for the construction of low-cost apartments for government employees and workers.
In private sector, several prominent realtors have already joined the apartment project, especially for middle up to high income people. Other institutions such as P.T. Pelindo, Perum Perumnas, Budha Tzu Chi have also
participated in the development of housing facilities.
It is worth mentioning that after earthquake and tsunami disaster, the rehabilitation of housing facilities dictates that strong and yet fast and low-cost housing facilities are badly needed in that region. Similarly, earthquake disaster in Yogyakarta requires low-cost housings. Several applications of precast concrete structure in part have provided such needed facilities.
6. CONCLUSIONS
about 600,000 units of housing are needed to construct annually, not to mention the back-log and restorations Applications of precast concrete structural systems for the construction of low-cost apartments have gained vast progress worldwide, and so to speak, in Indonesia as well. This is due to the fact that precast concrete systems have several advantages compared to the conventional cast-in-situ concrete systems. This fact has been utilized by the Government of Indonesia, to implement an accelerated progress in the development of public housing
facilities, in particular, low-cost rental and owned apartments.
To support the massive program, the Government of Indonesia has already launched a national moratorium on housing construction, referred to as GN-PSR. About 1000 low-cost apartment towers are expected to build in the period of 2003-2011. This program is backed up by the applications of about 22 precast concrete structural systems that already applied thus far.
2. RESEARCH ON PRECAST CONCRETE SYSTEMS IN INDONESIA
1. INTRODUCTION
The application of precast concrete structural systems have been attaining vast progress worldwide, particularly in Indonesia in the last few decades. This is due to the fact that the precast structural systems possess several advantages compared to monolithic systems, such as quality control, speedy construction, and suitable application to regularly modular systems. In the middle of 2006, the Indonesia Government launched massive and speedy construction of 1000 low-cost apartment towers nationwide. To cope with the enormous need, Indonesian prominent research workers have been developing several precast concrete structural systems. The paper deals with the research and the application of precast concrete structural systems in Indonesia. The paper also describes the vast development already achieved to date in the applications of the precast concrete structural systems in the constructions of low-cost apartments in Indonesia. The research and applications of precast concrete structural systems are intended to support accelerated construction of one thousand low-cost apartment tower throughout large cities in Indonesia.
