Two direct causes led to the collapse on September 11, 2001 of the World Trade Center towers: column damage caused by aircraft crash and the resulting large-scale fires. In spite of this damage, the towers remained standing after the crashes for 102 and 56 minutes, respectively, during which many lives were saved. | A Study on the Collapse Control Design Method for High-rise Steel Buildings by Akira Wada 1 Kenichi Ohi 2 Hiroyuki Suzuki 3 Mamoru Kohno 1 2 3 4 and Yoshifumi Sakumoto 5 ABSTRACT Two direct causes led to the collapse on September 11 2001 of the World Trade Center towers column damage caused by aircraft crash and the resulting large-scale fires. In spite of this damage the towers remained standing after the crashes for 102 and 56 minutes respectively during which many lives were saved. The collapse of the WTC towers however may be taken as an alert that local failures can trigger a progressive collapse. It was also a landmark event in that it alerted construction engineers to the importance of preventing progressive collapse in similar structures. Prevention of progressive collapse requires the development of design technologies for frames that have high redundancy. The Japan Iron and Steel Federation together with the Japanese Society of Steel Construction established the committee on The Study on Redundancy of High-Rise Steel Buildings in June 2002 in an attempt to study and provide a better understanding on progressive collapse by collaboration with Council on Tall Buildings Urban Habitat. This paper presents a new collapse control design method for high-rise steel building structures. The basic concept of the present collapse control design methods is to save human lives. Therefore the method presented here to prevent progressive collapse until the completion of evacuation makes assumptions about which structural members are likely to be lost and proposes the idea of key elements that are linked with a building s core section to serve as the evacuation route and consist of structural members indispensable for supporting redistributed vertical loads. KEYWORDS Collapse Control Design Key Element Progressive Collapse 1. INTRODUCTION The collapse of the World Trade Center towers WTC1 and WTC2 was the direct result of column damage and large-scale fires caused by .
