Febrin Anas Ismail

Assessing building vulnerability to earthquake and tsunami hazard using remotely sensed data

Quantification of building vulnerability to earthquake and tsunami hazards is a key component for the implementation of structural mitigation strategies fostering the essential shift from post-disaster crisis reaction to preventive measures. Facing accelerating urban sprawl and rapid structural change in modern urban agglomerations in areas of high seismic and tsunami risk, the synergetic use of remote sensing and civil engineering methods offers a great potential to assess building structures up-to-date and area-wide. This paper provides a new methodology contextualizing key components in quantifying building vulnerability with regard to sequenced effects of seismic and tsunami impact. The study was carried out in Cilacap, a coastal City in Central Java, Indonesia. Central is the identification of significant correlations between building characteristics, easily detectable by remote sensing techniques, and detailed in situ measurements stating precise building vulnerability information. As a result, potential vertical evacuation shelters in the study area are detected and a realistic vulnerability assessment of the exposed building stock is given. These findings obtained allow for prioritization of intervention measures such as awareness and preparedness strategies and can be implemented in local disaster management.

TSUNAMI MITIGATION EFFORTS WITH pTA IN WEST SUMATRA PROVINCE, INDONESIA

This paper describes tsunami disaster mitigation in the West Sumatra region with participatory technology assessment (pTA), which promotes direct interaction among member and experts to discuss issues and reach consensus for mitigation through provision of information and knowledge of science and technology. Two areas were examined: Padang, the capital city; and Painan city, a town in southern West Sumatra Province, Indonesia. Tsunami have damaged these areas at least three times: in 1797, a 5–10-m-high tsunami wave height hit the area; in 1833, a 3–4-m-high tsunami came; and in 2007, an 8.4 Mw earthquake generated a local tsunami with maximum wave height of 1.5 m, as observed near Painan. Because of the high level of tsunami risk resulting from its flat topographic conditions, their respective populations of 820,000 people and 15,000 people are developing tsunami mitigation efforts with support of national institutions and international experts. These cities had different starting points and approaches. Efforts were introduced to produce official tsunami hazards maps. Insights from these lessons and ideas arising from the ongoing process after the 2007 South Sumatra and 2009 Padang earthquakes are discussed herein.

FERROCEMENT - BRICK SANDWICH WALL APPLIED TO NON-ENGINEERED HOUSES

Indonesian houses are generally categorized as non-engineered buildings that are constructed without any proper structural analyses. Bricks have long been used for hundreds of years as main materials to make houses for the reasons of simplicity and construction speed. Lesson learnt from the Padang earthquake in 2009 concluded many casualties are resulted from the collapsed houses made of bricks. Ferrocement as a construction material that made of wire mesh and mortar plaster become alternative to be used for retrofitting brick-houses. In this paper, structural analyses of a typical non-engineered house and a retrofitted house made of ferrocement-brick sandwich material are described. The ferrocement-brick composite material has a role as the main structure in the non-engineered house. The series of tests on that sandwich material has been done prior to the analyses. The results of the tests are then used to determine the strength criteria of the analyzed house. A structural analysis of the house is done by using the finite element computer program. As a comparison, an analysis of an ordinary brick wall house is described. As previously thought, the house with walls made of the ferrocement-brick sandwich material can withstand the given earthquake loads. It is concluded that the ferrocement-brick sandwich material is very useful to build earthquake resistant houses in seismic prone areas such as the West Sumatra.

LIQUEFACTION POTENTIAL ASSESSMENT BASED ON LABORATORY TEST

The physical properties of sand soil which give effect to the resistance of liquefaction include grain size and density. Those physical properties of sand soil associated to liquefaction resistance have been studied in laboratory. Based on that study, the method to assess the liquefaction potential then is proposed. In laboratory tests, the vibration source is given by using the shaking table. During the tests, the acceleration and settlement are recorded. It then concluded that there is a relationship between density and gain size particles associated with liquefaction resistance for certain acceleration of vibration. The cone penetration and relative density relationship has been developed based on experiments in laboratory. Based on the results of those laboratory tests, the liquefaction potential of a certain site then assessed. It is found that the relative density and mean gain size relationship can be used to assess liquefaction potential in sand deposits.

Structural Response and Pounding of Andalas University Hospital Building Using New Indonesian Seismic Code SNI 1726-2012

Keywords: Earthquake, Internal Forces, Displacement, Response Spectrum Analysis, Time History Analysis, PoundingAbstract. Teaching Hospital is an educational facilitiy for students in the Faculty of Medicine and also as a health services for the general public. The hospital building must be built in accordance with earthquake-safe building standards, so that buildings are not damaged in an earthquake. Andalas University Hospital was built at Padang in 2014 which was designed using Indonesian Seismic Code SNI 03-1726-2002 with quakes zone 6. Since 2012, a new Seismic Code, SNI 1726-2012, was issued and all the buildings should be designed by using the new code. Therefore, the authors are interested in analyzing the structural response of the hospital building by using new seismic code SNI 1726-2012. The results, then, were compared with the responses of the structure which calculated by using SNI 03-1726-2002.The results of analysis show that the structural responses in the internal forces and displacement by using SNI 1726-2012 was higher than those using SNI 03-1726-2002. In this study, an analysis of potential Pounding was also conducted by using dynamic analysis Time History method. The analytical result shows that there is no pounding between adjacent buildings at Andalas University Hospital Buildings.

Retrofitting of STKIP ADZKIA Padang Building Using V-Inverted Steel Bracing

Construction failure is always associated with non-fulfillment of the quality and technical specifications of the material that should be considered when the construction process has been done. STKIP ADZKIA Padang building is one of 4-story reinforced concrete (RC) building that has structural damage during construction phase. The beams of the building undergo large deflection and the cracks appear in the wall when the building was constructed up to 2nd floor. In this paper, building assessment was carried out to evaluate the performance of the existing building. The structure was analysed based on New Indonesian Seismic Code, SNI 03-1726-2012. The result shows that the building is not capable to resist the working loads. Furthermore, retrofitting of the building structure using V-inverted steel bracing was proposed. The analysis result shows that retrofitting of the structure by installing the steel bracing on the RC frames in both X and Y directions increase the capacity of the building structure.