Collapsed-RC Building Failure Mechanisms with a Forensic Engineering Approach

Abstract

A reinforced concrete building in Konya, Turkey, collapsed suddenly on February 2, 2004, and 92 residents died. This case study was performed to determine the alternate load paths and failure mechanism of the building. The essence of a forensic engineering investigation of a construction failure is to determine the failure mechanisms by using the procedural causes and contributing factors. The building behavior under the sudden loss of ground-story columns and various scenarios of column removal was assessed. The site works and stepwise nonlinear analysis were applied to get the failure mechanism of the collapsed building. The lessons learned from this case study forensic investigation are discussed, and the construction and project errors beneath the collapse are identified. Torsion is not a desired first mode of dynamic behavior. The progressive collapse of the RC building was the torsional mode. In building due to architectural needs, i.e., lack of the beam in exterior frames, discontinuities in the three-dimensional (3D) structural framing and very low bonds existed in the RC beams, resulting in an improper redistribution of the forces.