新发表论文：探讨在不同楼层拆除竖向构件对连续倒塌行为的影响

Li Y, Lu XZ, Guan H, Ren PQ, Numerical investigation of progressive collapse resistance of RC frames subject to column removals from different stories. Advances in Structural Engineering, Accepted on Sep. 5, 2015. DOI:10.1177/1369433215624515

已有研究大多未深入分析不同楼层的柱子移除后造成的连续倒塌行为的差别。本文以一个典型框架结构为例，讨论了不同楼层及不同位置的柱子移除后对连续倒塌行为的影响。研究表明，当柱子移除后，上部结构会形成空腹桁架效应，各楼层分担的荷载比例不一样。且提高抗震设计对底部楼层抗连续倒塌能力提升较多，而对顶部楼层影响有限。本文还对不同规范中连续倒塌承载力计算结果进行了对比。

This paper presents a nonlinear static pushdown analysis to evaluate the progressive collapse-resisting capacity curves of typical RC frames under different deformation. Unlike the previous studies in which only a few typical columns, such as a column on the bottom storey, are removed, this study examines the column removal scenarios for various typical locations from different stories. The primary findings are: (1) the Vierendeel action causes different internal forces in the beams of different stories, which reduces the progressive collapse resistance under the beam mechanism and delays the development of the catenary mechanism. This may result in the beams fail successively from one floor to another in a frame system, which differs from the theoretical assumption that the beams are damaged simultaneously on different floors; (2) seismic designs significantly improve the progressive collapse resistance under the beam mechanism, especially for lower stories. However such an improvement is less significant for the catenary mechanism and little improvement is found for the top regions of the frame structures. Further, a nonlinear dynamic analysis is conducted to validate the predicted resistances of the RC frames in satisfying the requirement of collapse prevention. The design parameters as specified in the existing codes are also discussed.

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