Current Issue

THE MAJOR CAUSE OF HIGH-RISE BUILDING FAILURE DURING THE 921 JIJI EARTHQUAKE

Tse-Shan Hsu

Founding President, Institute of Mitigation for Earthquake Shear Banding Disasters

Professor, Department of Civil Engineering, Feng-Chia University, Taiwan R.O.C.

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Lin-Yao Wang

Ph.D. and Director, Bureau of Transportation and Public Works, Yunlin, Taiwan, R.O.C.

Abstract

Mat foundations, characterized by their large area and high load-bearing capacity, have traditionally been considered safe by scholars and experts without performing any verification tests. Consequently, cases of tilting and subsidence in high-rise buildings are often attributed to design flaws and inadequate construction practices. In this paper, the authors present a case study examining the tilting and subsidence failures of two high-rise buildings during the Jiji earthquake in 1999, with a focus on the changes in load-bearing capacity of mat foundations during seismic events. The results of this study reveal three key findings: (1) The shear banding effect can easily trigger soil liquefaction; (2) Soil liquefaction can cause a localized loss of load-bearing capacity in the mat foundations of high-rise buildings situated above shear banding zones; (3) When such localized losses occur, buildings may become susceptible to either tilting or subsidence failures. Based on the findings mentioned above, the authors recommend that seismic design codes for mat foundations incorporate provisions to address soil liquefaction induced by the shear banding effect, thereby ensuring the safety of high-rise buildings with mat foundations.

Keywords: high-rise building, mat foundation, shear banding, soil liquefaction.