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Irsyam M.,Bandung Institute of Technology | Asrurifak M.,Bandung Institute of Technology | Budiono B.,Bandung Institute of Technology | Triyoso W.,Bandung Institute of Technology | Firmanti A.,Research Institute for Human Settlements
Geomechanics and Geoengineering

The need to revise the current Indonesian Seismic Hazard Map contained in Indonesian Earthquake Resistant Building Code SNI 03-1726-2002 which partially adopts the concept of UBC 1997, was driven among others by the desire to better reflect the potential larger earthquake disasters faced by the nation in the future. The much larger than maximum predicted Aceh Earthquake (Mw 9.0-9.3) of 2004, followed by the destruction observed during the 2005 Nias Earthquake (Mw 8.7) urgently underline to need to consider the new conceptual approach and technological shift shown in the transition of UBC 1997 to IBC 2006. This paper presents research works for developing spectral hazard maps for Indonesia. Some improvements in seismic hazard analysis were implemented using recent seismic records. Seismic sources were modeled by background, fault, and subduction zones by considering a truncated exponential model, pure characteristic model or both models. A logic tree method was performed to account for the epistemic uncertainty and several attenuation functions were selected. Maps of PGA and spectral accelerations for a short period (0.2 s) and for a 1-s period were then developed using a probabilistic approach. The maps will be proposed as a revision for the current seismic hazard map in the Indonesian Seismic Building Code. © 2010 Taylor & Francis. Source

Bahtiar T.A.,Research Institute for Human Settlements | Kusunoki K.,Yokohama National University
Bulletin of the International Institute of Seismology and Earthquake Engineering

In the February 27, 2010 Chile Earthquake many medium height buildings with structural wall elements collapsed. According to damage surveys one of the factors associated with this structural failure was high flexural compression stress in flange walls. The objectives of this study are to evaluate the provision in the current standard for effective flange width in tension and compression, to clarify high compression stress in flange walls, and clarify the effect of porous sub-standard concrete on effective width. The effective flange width is the width of the flange that influences the lateral forces acting in the plane of the web wall. It is related to stress and strain distribution. As stress and strain distribution is nonlinear, to avoid nonlinearity used uniform distribution of stress and strain. This study is based on experimental testing of three specimens of symmetrical cross-sections walls (H-shaped). The Specimens are designed in accordance with Japanese standard at 1/3 scale acting monotonie or cyclic lateral and axial force. The output the tests is strain distribution in flange walls from each side of each specimen. Data was obtained by installing reinforcement strain gauges in all three specimens, as well as concrete strain gauges in specimen H2 to observe compression. Mechanical properties also analyzed in this study to determine stress-strain relationship models. Bilinear model for steel and trilinear model for concrete used to obtain stress. Effective flange width is calculated by divided the area of stress distribution with the maximum stress. From these tests it is concluded that effective width should be greater than standard provisions for both tension and compression. In cyclic tests, effective flange width for compression is greater than for tension, before compression is neglected. In general, it is indicated that the use of sub-standard concrete does not significant effect to effective flange width. Source

Wibowo A.,Research Institute for Human Settlements | Wibowo A.,TU Berlin | Kochendoerfer B.,TU Berlin
Journal of Construction Engineering and Management

Guarantee provision in privately financed infrastructure projects implemented as build-operate-transfer/public-private-partnership (BOT/PPP) arrangements is not uncommon in many countries, and Indonesia is no exception. But, given that the government budget is, in most if not all cases, not unlimited, there must be a selection of BOT/PPP projects posing proposals for seeking government guarantees. This paper presents a project selection methodology under the chance-constrained goal-programming framework in the context of the Indonesian BOT/PPP infrastructure industry. The ultimate objective of the selection is to result in a portfolio of guaranteed projects that brings maximum welfare gain to the economy as a whole, maximum total net change in financial net present value but, at the same time, puts the government at the lowest fiscal risk for a given budget constraint. The proposed methodology allows the government to examine relationships among the expected total payment, budget-at-risk allocated, and a desired confidence interval of actual payment not exceeding the budget-at-risk. The government can also compare two or more alternative scenarios and choose the optimal one that delivers the highest value for the money. To illustrate the model application, without sacrificing the generality of the proposed methodology, a much-simplified hypothetical case is presented, examined, and discussed. © 2011 American Society of Civil Engineers. Source

Hastuti E.,Research Institute for Human Settlements | Wardiha M.W.,Denpasar Experimental Station for Traditional Housing Technology Development
Journal of Urban and Environmental Engineering

Water pollution and sea water intrusion to water sources in coastal areas result lack of provision safe drinking water by the drinking water regional company or coastal community. The existing water treatment plant that operated on brackish surface water or groundwater feed requires improving process. Membrane process could be a choice to treat the quality of brackish water to the level of potable water that designed to lower cost with high stabile flux and longer lifetime. This research focus on application of pilot plant of brackish water treatment using Ultrafiltration (UF) membrane-air lift system as pretreatment of Reverse Osmosis (RO) membrane-low pressure. Brackish water sources contain high colloidal and suspended solids that can cause fouling load of RO membranes and impair its performance. UF pretreatment operation tested by addition of compressed air into the feed (air lift system), resulted stable flux, reduces membrane fouling and low feed pressure. A flux of RO with UF pretreatment can produce drinking water of 30-61 L/m2·hour. It was observed, the good quality of RO permeate resulted by using a pretreatment of UF-PS (Polysulfone-UF) with total dissolved solid rejection about 96-98% and color rejection about 99-100% at 5 or 8 bars of operation pressure. This paper concludes that performance of membrane technology with UF-air lift system pretreatment and RO membrane-low pressure could be accepted as condition of brackish water source in Indonesia coastal areas in producing drinking water. © 2012 Journal of Urban and Environmental Engineering (JUEE). All rights reserved. Source

Hadi M.,Research Institute for Human Settlements | Setiadji R.,Research Institute for Human Settlements | Firmanti A.,Research Institute for Human Settlements | Subiyanto B.,Indonesian Institute of Sciences | Komatsu K.,Kyoto University
World Conference on Timber Engineering 2012, WCTE 2012

The low-cost housing for the people is the main program of Indonesian government. In addition these low-cost homes it must be meet the standards of healthy house and earthquake resistant. In this study, an experiment on composite shear walls has been carried out to determine structural reliability; this is necessary information for practitioners when constructing the earthquake-resistant houses. Analytical and experimental approaches have also been conducted, to establish an appropriate method to estimate the performance of this kind of structure that can be used in the future. Analytical calculation and the test of composite shear wall material of Hevea brasiliensis- Paraserianthes Falcataria Laminated Veneer Lumber (LVL) as a frame member and sheathed by 9 mm thick of Glass fiber Reinforced Concrete (GRC) panel, fastened by nail has been carried out. The structural system consisting of wood and cement-based building materials, shows sufficient resistance to earthquake, and so the shear wall panel can be used as a structural element in pre-fabricated houses and earthquake- resistant residential buildings. Source

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