轻骨料混凝土深受弯构件压杆隔离体开裂软化性能试验研究  

Experimental study of cracking softening performance of strut isolation specimen in lightweight aggregate concrete deep flexural member

作　　者：张玉[1] 吴涛[1] 王立勋[1] ZHANG Yu;WU Tao;WANG Lixun(School of Civil Engineering,Chang′an University,Xi′an 710061,China)

机构地区：[1]长安大学建筑工程学院,陕西西安710061

出　　处：《大连理工大学学报》2021年第4期383-390,共8页Journal of Dalian University of Technology

基　　金：国家自然科学基金资助项目(52078042,51878054).

摘　　要：完成了11个不同参数的轻骨料混凝土深受弯构件斜压杆隔离体试件轴压性能试验,系统研究了其破坏过程、荷载-位移曲线、破坏形态以及钢筋混凝土应变等;深入分析了压杆腹筋配筋率、高厚比对该类构件有效抗压强度系数及破坏形态的影响;评估了EC2规范、ACI 318-19规范、Model Code 2010规范等的拉-压杆模型及学者提出的斜压杆承载力计算模型对该类构件的适用性与准确性.计算结果表明:轻骨料混凝土深受弯构件斜压杆主要发生压杆区破坏和节点区破坏两种破坏形态,随着压杆腹筋配筋率增大,破坏形态逐渐由压杆区破坏向节点区破坏转化,且斜压杆压应力扩散范围逐渐减小;斜压杆试件高厚比减小,试件混凝土有效抗压强度系数增大,尺寸效应明显;基于拉-压杆模型的规范和学者提出的斜压杆承载力计算模型结果与试验结果相比较为保守.Eleven inclined strut isolation specimens in the deep flexural members were tested for their axial compression behavior.The members were made of lightweight aggregate concrete with different parameters.The failure process,load-displacement curves,failure mode and the strain of reinforced concrete were studied systematically.The influence of reinforcement ratio of web reinforcement,height-thickness ratio of strut on the efficient compression strength coefficient and failure mode was deeply analyzed.The feasibility and accuracy of strut-and-tie model from EC2 code,ACI 318-19 code and Model Code 2010,and inclined strut bearing calculation model proposed by researchers were tested.The calculation results show that there are two typical failure patterns for inclined strut isolation specimen in lightweight aggregate concrete deep flexural member,that is,the tensile failure and concrete crushing at node failure.It is shown that with the increase of reinforcement ratio of strut web reinforcement,the failure modes change gradually from the tensile failure to concrete crushing at node failure,and the spread scope of the inclined strut compressive stresses decreases gradually.With the decrease of strut height-thickness ratio,the efficient compression strength coefficient of specimens concrete increases significantly and the size effect of inclined strut is significant.The calculation results using the strut-and-tie model from codes and the inclined strut bearing calculation model proposed by researchers are more conservative while compared to the results of test.

关 键 词：轻骨料混凝土 深受弯构件 拉-压杆模型 压杆隔离体 软化系数 

分 类 号：TU375.1[建筑科学—结构工程]