摘要
通过试验与有限元分析研究焊接连接预制混凝土(PC)梁-板子结构的抗连续倒塌性能。在实验室制作1个焊接连接PC梁-板子结构缩尺模型,采用Pushdown加载方法并考虑工作荷载对结构倒塌过程的影响,研究该子结构在去除1个边柱工况下的抗力曲线、梁板变形、钢筋应变及有效抗力机制。试验结果表明,尽管假设动力放大系数为2.0,试验模型在瞬间移除1个边柱工况下也不会发生连续倒塌,焊接连接PC试件的破坏首先发生于焊缝处栓钉断裂。为了解焊接连接PC子结构抗倒塌机理及各主要构件的抗力贡献,通过商业软件ANSYS/LSDYNA进行数值分析并开展拓展分析。通过对比试验及有限元模拟结果发现,采用LSDYNA软件可以准确模拟试件的破坏模态及受力特性。有限元分析结果表明:在受荷初始阶段,预制板及叠合层对抗倒塌承载力的贡献只占30%,抗力主要由预制梁发展梁机制承担;但是在后期大变形阶段,预制板及叠合层对抗倒塌承载力的贡献可高达80%,叠合层中的钢筋网发展拉膜作用是后期大变形阶段试件的主要抗力机制。
The paper investigates the performance of precast concrete(PC)beam-slab substructures with welded connections against progressive collapse through experiment and finite element analysis.A one-third scaled PC beamslab substructure model was built in laboratory.The effect of service pressure on the behavior of test model was considered.Based on Pushdown load method,the resistance curve,beam deformation,local strain and effective resistance mechanism of the substructure under the scenario of removing one side column were measured.The experimental results indicate that even if the DIF(dynamic increase factor)is assumed to be 2.0,the PC model still could survive if only an exterior column is lost.The failure mode of test model is dominated by the brittle fracture of the studs at the welding feet.Then,using the high fidelity finite element software ANSYS/LSDYNA,a series of numerical analyses were also carried out.The comparison of the FEA results with the test ones indicates that FE model is able to reproduce the behavior of PC beam-slab substructures suffered from column missing scenario.Based on the following parametric study,the FEA results show that in the initial stage of loading,the contribution of the prefabricated slab and laminated layers against collapse bearing capacity only accounts for 30%,and the resistance is mainly provided by the beam mechanism of prefabricated beams.However,in the later stage of large deformation,the contribution of the prefabricated slab and laminated layers against collapse bearing capacity can be as high as 80%.In addition,the development of the tensile strength of the steel mesh in the laminated layer is the main resistance mechanism of the specimens at later large deformation stage.
作者
李治
翁运昊
邓小芳
钱凯
LI Zhi;WENG Yunhao;DENG Xiaofang;QIAN Kai(College of Civil Engineering and Architecture,Guangxi University,Nanning 530004,China;College of Civil Engineering and Architecture,Guilin University of Technology,Guilin 541004,China)
出处
《建筑结构学报》
EI
CAS
CSCD
北大核心
2020年第10期121-128,共8页
Journal of Building Structures
基金
国家自然科学基金项目(51778153,51568004,51478118,51678164)。
