Progressive Collapse Mitigation: Geometrically Nonlinear Catenary Behavior

摘要

Progressive collapse is defined as the spread of a localized structural failure to other structural members resulting in a disproportionate collapse of the global system. Building codes suggest one method of mitigating progressive collapse involves provisions for load resistance through catenary behavior across two-span conditions caused by the loss of column support. In concrete structures, reinforcing steel is one potential source of catenary load carrying capacity. Currently, design codes allow static approximations of the dynamic systems for design. While this approach is appropriate for many structural systems, the catenary behavior of a two span reinforced concrete beam provides opportunities for closer investigation of its static and dynamic behavior. This paper presents analytical and experimental investigations of geometrically nonlinear static and dynamic analyses which characterize the behavior of the catenary system. As a first approximation to the behavior of the complex system, an analysis and experimental evaluation of the behavior of a bare steel wire is examined. Geometrically nonlinear effects, even in the linear elastic regime, are significant. The result of this work is an analytical (and experimentally corroborated) characterization of catenary behavior of reinforcing steel that may be used by researchers, code developers, and designers to estimate catenary capacity under a variety of conditions.