摘要
为研究不同跨度比对组合梁柱结构抗倒塌性能的影响,以栓焊连接节点组合梁柱子结构(两跨三柱型)为研究对象,以相邻跨度的比值(简称跨度比)为试验参数,对3个不同跨度比(1.4∶1、1.0∶1、0.6∶1)的子结构进行单调静力加载试验,考察了其在中柱失效后的抗倒塌性能。试验结果表明,3个试件的变形形态基本相似,试件在加载过程中表现出多次间断性破坏特征,当失效柱与梁端受拉翼缘连接处发生断裂后,对应梁端截面弯矩急剧下降导致其受弯性能大幅降低,该组合梁的悬链线机制抗力超过梁机制抗力贡献起到主要作用;而未发生破坏的梁,其受弯性能下降不明显,此时主要通过梁机制和悬链线机制共同抵抗外荷载,表现出双跨梁抗力机制的不同步性。试件在梁机制阶段,随着跨度比的减小,3个试件的塑性荷载依次提升,初始断裂位移随之减小,并且相比非等跨试件,等跨试件因双跨组合梁之间的协同作用可使结构在大变形阶段提供高于前期受弯阶段的抗力。引入抗力贡献系数,定量分析了3个试件双跨梁不同的抗力机制分别对总抗力的贡献占比。基于能量平衡原理获得了组合梁柱子结构在突加外荷载作用下的结构动力响应,可将最大动力荷载点作为组合梁柱子结构是否发生倒塌的依据。
To investigate the influence of different span ratios on the anti-collapse performance of composite beamcolumn structure,three composite beam-column assemblies with different span ratios(1.4∶1,1.0∶1,0.6∶1),which were each comprised of three columns and two beams with the bolt and weld rigid connections,were studied.Through static loading tests,the anti-collapse performance of the three specimens under a middle column removal scenario was investigated.The test results indicate that the deformation modes of the three specimens are similar:they all show failure characteristics of multiple and intermittent damage.When the tension flange of the beam near the failed column fractures,the bending moment of the corresponding beam end decreases sharply,resulting in a significant decrease in the bending capacity.At that time,the resistance of the catenary mechanism plays a major role and exceeds the contribution of the resistance of the flexural mechanism.The bending capacity of the beam without damage is not obviously reduced,and the external load is mainly resisted by the flexural mechanism and the catenary mechanism,which shows an asynchronism in the resistance mechanism of two-bay beams.The plastic load of the three specimens increases with the span ratio decrease in flexural action phase,and the initial fracture displacement decreases correspondingly.The specimen with equal spans could provide higher resistance in the large deformation stage than in the flexural stage due to the synergistic effects of two-bay beams.The contribution coefficients of resistance are introduced to quantitatively analyze the contributions of different resistance mechanisms to the total resistance of twobay beams.The structural dynamic response of the composite beam-column assemblies under sudden external loads can be obtained based on the principle of energy balance,and the maximum dynamic load point can be used as the basis for determining whether the collapse of the composite beam-column assembly may occur.
作者
钟炜辉
谭政
宋晓燕
孟宝
ZHONG Weihui;TAN Zheng;SONG Xiaoyan;MENG Bao(School of Civil Engineering,Xi’an University of Architecture and Technology,Xi’an 710055,China;Key Lab of Structural Engineering and Earthquake Resistance of China Ministry of Education,Xi’an University of Architecture and Technology,Xi’an 710055,China)
出处
《建筑结构学报》
EI
CAS
CSCD
北大核心
2020年第9期45-55,共11页
Journal of Building Structures
基金
国家自然科学基金面上项目(51678476)
陕西省重点研发计划(2018ZDXM-SF-097)
中国博士后科学基金面上项目(2018M643593)。
关键词
组合梁柱子结构
栓焊刚性连接
跨度比
静力试验
抗倒塌机制
composite beam-column assembly
bolt and weld rigid connection
span ratio
static test
anti-collapse mechanism
