Are the frail designed to fail? Assessing the collapse risk of existing structures

• Main Authors: Li, Bing, Qian, Kai
• Other Authors: School of Civil and Environmental Engineering
• Format: Conference or Workshop Item
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Civil engineering::Structures and design
• Online Access: https://hdl.handle.net/10356/99725; http://hdl.handle.net/10220/24049
• Institution: Nanyang Technological University

The catastrophic after-effects of the historical collapse events have received considerable attention from government agencies, research communities, and practical engineers on the aspect of the evaluation of the risk of progressive collapse of buildings. In the recent decade, numerous studies have been conducted to answer the question: are the frail designed to fail? In this paper, the research outcomes from experimental and analytical studies are discussed in an attempt to answer above critical question, which mostly concerned by building owners or decision makers. The findings from previous studies had indicated that the buildings, which had a regular layout, moderate span, and cast-in-place construction method, may have lower collapse risk. This is mainly due to the slab and infill walls providing additional stiffness and strength to resist sudden columns removal. Moreover, considerable second load carrying mechanisms, such as catenary action, arch action, and compressive or tensile membrane actions could develop in beams or slabs, which further reduces the possibility of progressive collapse. Furthermore, the recent dynamic tests have revealed that the dynamic effects were not as large as the value proposed by provision of guidelines. However, for structures with irregular layout, which is very popular in nonseismic zones, such as Singapore or Hong Kong, may undergo a much higher likelihood of collapse. Moreover, the high vulnerability of newly designed precast structures with extreme large design span could not be ignored. It should be further emphasized that multi-hazards due to terrorist attack, which was ignored in existing design guidelines, may lead to the collapse of the buildings brining about tragic consequence.