局部爆炸作用下混凝土框架结构抗连续倒塌设计

Design of Reinforced Concrete Frame Structures to Resist Progressive Collapse under Blast Loading

采用替代路径法对按我国规范设计的钢筋混凝土框架结构进行局部爆炸作用下抗连续倒塌设计验算和再设计。竖向构件移除位置、荷载组合、构件失效准则以及结构破坏范围限值均参考美国《结构抗连续倒塌设计》(UFC4-023-03)中的规定,改进了其中的构件塑性铰模型,采用条分法得到了纯弯和压弯构件塑性铰的荷栽-变形全过程,以合理描述构件受力性能。研究发现,常规设计难以保证结构在局部爆炸作用下不发生连续倒塌。随后进行了参数研究,以认识重要参数对结构抗连续倒塌性能的影响。结果表明,减少柱距后结构抗连续倒塌性能提高明显,而提高结构抗震设防烈度的方法效果不明显,增加结构层数则会削弱结构的抗连续倒塌能力。在此基础上给出了三个抗连续倒塌设计方案并进行了经济性比较。比较表明,同时提高结构的冗余度和构件的承载力具有较好的经济性。

Following the provision addressed in ＂Design of Structure to Resist Progressive Collapse＂ （ UFC 4 -023 -03 ）, including the removal locations of vertical load-bearing elements, loads combination, failure criteria for structural elements and damage limits of RC structures, a design study on reinforced concrete frame structures to resist progressive collapse under blast loading was carried out by using alternate path method. The structure was originally designed in accordance with the current Chinese design code. The full load-deformation development of plastic hinges for flexural and compressive-flexural members was also considered by using fiber model. It was found that the originally designed structure can not meet the design requirements to resist progressive collapse. Then a parameter study was conducted to understand the influence of some factors on the structural performance to resist progressive collapse. Results indicate that it significantly improves the performance of RC frame structure to resist progressive collapse to reduce the column span, while it has indistinctively effect to enhance the seismic fortification criterion and the capacity of a structure to resist progressive collapse will be weakened by increasing the stories of the structure. Finally three design schemes for the building to resist progressive collapse were proposed with a brief economic comparison, among which the design scheme to increase the redundancy of the structure and the bearing capacity of structural members simultaneously is the optimum plan.