Verification and Validation of a Nonlinear Analysis Model for Ponding

Structural demands from rain loads can control the design of roof systems, especially those with large, flat bays where the accumulation of water due to deflections, known as ponding, amplifies the load. Under ponding conditions, insufficient strength or stiffness of the roof system can lead to instability and collapse. A variety of procedures for elastic analysis of ponding exist; however, few models consider material or geometric nonlinearity in addition to the ponding nonlinearity. A recently developed analysis model that uses the OpenSees finite element framework is capable of capturing material, geometric, and ponding nonlinearity. In this work, the analysis model will be verified and validated through comparisons to previously published analytical and experimental results, including results from a pair of large-scale experimental tests on open web steel joist roofs. These comparisons demonstrate that the analysis model is efficient and accurate in capturing the behavior of roofs subjected to ponding conditions up to incipient collapse.

Learning Objectives:
Describe how the effects of ponding can be included in a structural analysis.

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