Dyah Kusumastuti

Post-Disaster Housing Reconstruction in Indonesia: Review and Lessons from Aceh, Yogyakarta, West Java and West Sumatera Earthquakes

The post-disaster situation offers opportunities to rebuild liveable environment for achieving safer communities in the future, and housing reconstruction plays a crucial role in rebuilding the communities. In the past decade, Indonesia has experienced several major destructive earthquakes causing severe damages to infrastructures and human settlements. An ex-post review of the past experiences and challenges in post-disaster housing reconstruction after earthquakes in Aceh (2004), Yogyakarta (2006), West Java (2009) and West Sumatera (2009) reveals some strategic issues in implementing safer housing reconstruction that have to be addressed in the future for achieving “build back better” post-disaster reconstruction programs. Past experiences showed that training and capacity building of construction personnel and home-owners, through the dissemination of guidelines and manuals as well as building codes and standards for anti-seismic design, which have been implemented in the housing reconstruction programs by the national and local governments, NGOs and aid agencies have improved the practices by builders and masons in the areas that had experienced major earthquakes, but in general the attitudes of the building industry as well as local government building administrators in ensuring the housing earthquake safety still need to improve. Nevertheless, some good practices have been observed in several post-disaster housing reconstruction programs that shed the light to the development of better strategies for achieving earthquake safer housing, through the introduction of various supporting policies such as better project delivery systems, better mechanism for providing supervision and technical advices, more down-to-earth training and capacity building mechanism as well as smarter financing and incentives system, supported by appropriate technology approaches. Awareness building program is an important part of the mechanism and should be taken out seriously as it affect significantly the risk perception of the stakeholders, which is one of the key elements in the decision making process in investing for safer housing.

Proposed Site-Specific Response Spectra for Surabaya-Madura Bridge

A meshless local Petrov-Galerkin (MLPG) method that employs polygonal subdomains constructed from several triangular patches rather than the typically used circular subdomains is presented. Moving least-squares approximation is used to construct the trial displacements and linear, Lagrange interpolation functions are used to construct the test functions. An adaptive technique to improve the accuracy of approximate solutions is developed to minimize the computational cost. Variable domain of influence (VDOI) and effective stress gradient indicator (EK) for local error assessment are the focus of this study. Several numerical examples are presented to verify the efficiency and accuracy of the proposed adaptive MLPG method. The results show that the proposed adaptive technique performs as expected that is refining the problem domain in area with high stress concentration in which higher accuracy is commonly required.The effect of loading on the chloride penetration into plain concrete (PC) and fiber reinforced concrete (FRC) was studied experimentally by using modified NT Build 492 – Nonsteady state chloride migration test that include the application of loading on the specimen during the test. Three types of polypropylene fibers with different lengths and shapes were used. The concretes were tested for chloride penetration at different stress ratios under static and cyclic loading. The results of the static loading showed that there was a slight reduction in the chloride penetration under low level of compressive stress while an increase in the chloride penetration was found at higher stress level. There are significance difference in chloride penetration behavior of the plain concrete, long fiber FRC and short fiber FRC. Chloride penetration increased even more at cyclic loading conditions showing difference behavior of FRC and PC at difference number of cycle and load level.Billet scales are by-products from steel rolling mills in Nigeria that presently constitute environmental pollution. This paper reports studies carried out using these solid wastes as a partial replacement for sand in the production of concrete. Various percentages of billet scales were used in a concrete mixture of 1: 2: 4 by weight to cast concrete specimens. The compressive and tensile strengths developed were tested after 7, 14, 21, and 28 days of curing. The result of the compressive and splitting tensile strengths tests indicated that concrete strength increased with curing age. The compressive strength of 0%, and 15% replacement of sand with billet scales as obtained at 28 days are 26.0N/mm2, 26.2N/mm2. 15% optimal replacement of sand with billet scales had similar results as the control mixture of 0%, which could be used in reinforced concrete structures. Other replacements could be useful as mass concrete for non-structural construction applications.This paper presents a site-specific seismic hazard study to determine the recommended seismic design criteria for Suramadu Bridge. The study is performed using probabilistic seismic hazard approach to determine maximum acceleration and response spectra at bedrock and followed by local site effect analysis to determine maximum acceleration and response spectra at ground surface. The probabilistic seismic hazard analysis (PSHA) is carried out using 3-dimension (3-D) seismic source models (fault source model). Two hazard levels are analysed to represent 150 and 3,300 years return period of ground motion around site location. The local site effect analysis is performed using 1-dimension (1-D) shear wave propagation theory to obtain peak ground acceleration and response spectra at ground surface. Finally, the site-specific surface response spectra with 5 percent damping are developed based on the mean plus one standard deviation concept from the result of local site effect analysis.Appropriate trust and leadership have been frequently cited as key answer to the problems of cooperation and coordination in contractor’s teamwork. The objectives of this paper are to measure trust level of construction projects team, to investigate trustworthy leadership behavior of project managers, and to model the influence of project managers’ trustworthy leadership behavior upon team trust level. Sixty-one respondents from nine on-going construction projects participated in the questionnaire survey. The analyses show that in general the levels of trust and project managers’ trustworthy leadership behavior are medium (scores of 82.71 and 102.09 respectively). Meanwhile the positive influence of project managers’ trustworthy leadership behavior upon team trust level, modeled through multiple regression analysis with one dependent variable (i.e. trust) and three independent variables (i.e. leadershipresults, leadership-integrity, and leadership-concern), is found to be significant. The model is evaluated and validated; the results reveal that the prediction of the model is satisfactory.

Numerical study on the modification of long links in eccentrically braced frame

In anticipating damages to buildings caused by earthquakes, many types of building constructions have been developed and studied. One of these is eccentrically braced frames that uses the link element as part of the structural element that serves to absorb seismic energy. When tested for its ductility, strength, rigidity and energy absorption, the long link performed more poorly compared to short ones. However, advantages of using long links includes space for architectural design and the ease of meeting building requirements. The focus of this study is to provide information on using supplemental double stiffeners on both sides of the web at the ends of long links. The behavior of long links is maintained by positioning the flange failures at the end of the link. The supplemental double stiffeners can improve performance of the long link due to the extension of the inelastic zone and the slowing of failure in the flange at both ends of the link. A numerical study was carried out on several specimens of t...

Learning on the Safety Issues of Reconstructed Houses from the 2004 Great Indian Ocean Earthquake and Tsunami in Aceh, Indonesia

The 2004 Great Indian Ocean Earthquake and Tsunami has provided an opportunity to build a safer Aceh, Indonesia, through reconstruction of houses, buildings and infrastructures during the recovery process. A research conducted in 2006 to investigate and assess the house rebuilding practices of various actors in the reconstruction process produced the following findings. To improve the safety of the houses, planning and design should be improved so that the needs of the communities match with the reconstruction efforts, proper seismic designs should be ensured to avoid severe damage from future earthquakes, building materials should be improved to meet minimum requirements, quality of workmanship should be enhanced and good project management and supervision should be introduced to improve structural quality.