Investigation and Analysis of Buildings Damaged during the September 2007 Sumatra, Indonesia Earthquakes

Abstract

Earthquakes occurring on September 12 (8.4 M L ) and 13 (7.9 M L ), 2007, in South and West Sumatra, Indonesia, respectively, damaged many buildings. This paper reports investigation results on damaged buildings in and around Padang, West Sumatra, and discusses the seismic performance of two reinforced concrete (RC) frame structures with unreinforced masonry (URM) brick walls.Observations revealed that several RC structures with URM walls suffered severe damage such as shear failure of columns, buckling of column longitudinal reinforcements, and collapse of brick walls. In confined and simple URM structures, damage mainly to brick walls was observed. On the contrary, timber structures performed relatively well during the earthquakes.Two calculations were performed-one with and one without infill walls, focusing on two three-story collapsed and surviving RC buildings in Padang. A distinct difference was identified between the seismic performance of the two buildings when considering infill walls. Therefore, these samples of earthquakedamaged buildings verify that nonstructural infill walls can significantly contribute to the seismic performance of this type of structure.

R/C frame–infill interaction model and its application to Indonesian buildings

“…Padang city, the capital of West Sumatra province, suffered moderate/serious damage because of the 2007 /2009 earthquakes. The authors conducted a post‐earthquake field investigation in Padang city after the 2007 events—namely, the main shock and aftershock on 12 and 13 September 2007 (Indonesian local time)—to collect data on the typical structural details and damage . The investigation focused on two typical, adjacent three‐story R/C buildings: one totally collapsed and one moderately damaged, as shown in Figure .…”

“…Damage to the columns in the surviving building was investigated in detail by the authors to categorize the damage grade according to the Japanese guidelines put forward by Nakano et al . The grade was classified as ‘moderate damage’ for the first story, as reported in the authors' previous paper .…”

“…Consequently, the equivalent strut width is presented as a function of frame–infill contact length. The effectiveness of the proposed model is also verified by comparisons with the experimental results of a series of structural tests of brick masonry‐infilled R/C frames representing a typical R/C building with nonstructural masonry elements damaged by the 2007 Sumatra, Indonesia, earthquakes . Moreover, the proposed model is applied to two R/C buildings damaged by the 2007 earthquakes to investigate the infill effects on the damage conditions and the seismic performance.…”

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“…Struktur rangka beton bertulang dengan dinding bata (RC frame with brick masonry wall) sangat banyak dan umum dipakai di Sumatra Barat, Indonesia, baik untuk bangunan tingkat tinggi, menengah dan bangunan tingkat rendah. Berdasarkan peristiwa gempa yang terjadi dalam 1 (satu) dekade terakhir di Sumatra Barat, banyak bangunan beton bertulang yang rusak dan roboh (Maidiawati et. al, 2008dan EERI, 2009.…”

Seismic Performance of Existing R/C Building with Irregular Floor Plan Shape

“…Based on the experience of a major earthquake that occurred in West Sumatra-Indonesia on 30 September 2009, many caused the collapse of the building structure. The collapse of reinforced concrete buildings is generally caused by failure of the column structure [1]. On the other hand, the irregular shape of the floor plan has a profound effect on the movement of the building.…”