DAMAGE INVESTIGATION AND RE-ANALYSIS OF DAMAGED BUILDING AFFECTED BY THE GROUND MOTION OF THE 2009 PADANG EARTHQUAKE
Keywords:
Reinforced concrete, Building assessment, Seismic designAbstract
The purpose of this paper is to introduce a complete assessment to damaged buildings due to
earthquake event in earthquake-prone areas. Padang city is located on the western part of the island of Sumatra,
Indonesia, an earthquake-prone area. One of the largest earthquake events (Mw 7.6) occurred on 30 September
2009, striking the west coast of Sumatra. A total of 106,658 houses and 4,000 other buildings suffered damage
classified from slight to severe, and a reported 1,117 people were killed. Some large-scale reinforced concrete
buildings in Padang, as the capital of West Sumatra province, were also damaged. In order to determine the antiseismic deficiencies of these buildings, the authors assessed three buildings (BPKP, UNP and PU building) on
soft soil (the predominant period is greater 2s and Vs30<150m/s), and re-analyzed the BPKP building based on
the simulated ground motion of this earthquake event. In applying the current Indonesian seismic design code for
the BPKP building and visual checks by applying Japan Building Disaster Prevention Association (1991) to
evaluate the degree of damage at two further buildings, the results of this re-analysis revealed that one of these
buildings did not satisfy the demand capacity. By computing, the effects of local soil conditions on ground
motions from station ADS (Vs30 > 400m/s) to the BPKP building (Vs30<150m/s), the peak ground motion
acceleration at BPKP was found to have amplified 1.47 times. This result enables us to conclude that the soil
characteristics (rock to soft) influence ground motion amplification and affect the degree to which buildings suffer
damage.