Consequences of Tall Building Collapse the Urban Environment

摘要

Current approaches to seismic design, structural evaluation and risk assessment (including ratings) address each building apart from its neighbors. However, for tall buildings in the dense urban environment, the consequences of collapse must be considered, since the collateral damage from tower collapse in sidesway can multiply the life-safety and economic consequences dramatically. In this paper, we show simple, approximate methods to estimate the increase in collapse probabilities for groups of closely-spaced tall buildings, and project the corresponding increase in life-safety and economic consequences. We then show how the same methods can be used to identify the "bad actors" in the group that present a disproportionate danger. Such buildings are typically older, and many possess serious structural deficiencies known to increase their collapse fragility. Based on this more comprehensive approach to collapse risk, buildings may then be targeted for detailed evaluation, and (where risks are confirmed) for collapse-prevention retrofit. Other actions may be considered in the design of new buildings, in earthquake insurance coverage, and in planning for response and recovery.