成型钢筋混凝土柱抗震性能非线性有限元分析

Nonlinear Finite Element Analysis of Seismic Performance of Formed Reinforced Concrete Columns

成型钢筋是采用机械加工成型的钢筋制品,能有效提高钢筋加工质量与效率,降低加工成本,减少废料损耗,具有广阔的应用前景。目前,有关成型钢筋混凝土构件的研究主要集中在楼板和剪力墙方面,对柱的研究则相对较少。基于有限元软件ABAQUS,建立了成型钢筋混凝土柱的滞回分析模型。基于完成的3根成型钢筋混凝土柱抗震试验研究结果,验证了该模型合理性。在此基础上,开展了有限元参数分析,主要参数包括成型方式(穿箍、绕箍)、轴压比(0.2,0.4,0.6,0.8)、混凝土强度等级(C30,C40,C50,C60)、纵筋配筋率(0.78%,1.1%,1.5%,3.0%)、配箍率(0.45%,0.7%,1.0%)及箍筋构造(体积配箍率相同,双肢或三肢)等。分析结果表明:穿箍成型、绕箍成型和绑扎对比试件的承载力相近,相差≤5%;当轴压比从0.2增加到0.8时,试件的承载力提高22%,而延性系数下降42%;当纵筋配筋率从0.78%增加到1.5%时,试件的承载力提高31%,延性系数提高11%,而当配筋率从1.5%增加到3.1%时,试件的承载力提高39%,延性系数则降低52%;当纵筋配筋率从0.78%增加到1.5%时,双肢箍试件比三肢箍试件的延性系数高约20%,而当配筋率从1.5%增加到3.1%时,双肢箍试件的延性系数较三肢箍试件低约25%,这主要是由于在高配筋率情况下三肢箍对截面约束效果更好所致。

Formed steel bars are steel bar products that are shaped through machining processes,which can effectively improve the efficiency and quality of steel bar processing,reduce processing costs,and reduce waste loss.Compared with the traditional binding steel bar process,formed steel bars have broad application prospects.However,the current research focus on formed reinforced concrete members primarily revolves around floor slabs and shear walls,while studies on the seismic performance of formed reinforced concrete columns are relatively limited.To address this research gap,a finite element analysis model of formed reinforced concrete columns was established using ABAQUS software.The model’s validity is verified through tests conducted on three formed reinforced concrete columns.Subsequently,a finite element parameter analysis of formed reinforced concrete columns was conducted.The analysis encompassed various parameters,including formed methods(inserted formed,winded formed),axial compression ratios(02,04,06,08),concrete strength grade(C30,C40,C50,C60),longitudinal reinforcement ratio(078%,11%,15%,30%),stirrup ratio(045%,07%,10%)and stirrup configuration(two limbs,three limbs)and so on.The research findings indicate that the bearing capacity of inserted formed,winded formed and binding comparison specimens are similar,with a difference of no more than 5%.As the axial compression ratio increases from 02 to 08,the bearing capacity of the specimens increases by 22%.Simultaneously,the ductility coefficient decreases by 42%.When the reinforcement ratio of longitudinal reinforcement increases from 078%to 15%,the bearing capacity of the specimen increases by 31%,and the ductility coefficient increases by 11%.However,as the reinforcement ratio further increases from 15%to 31%,the bearing capacity of the specimen increases by 39%,but the ductility coefficient decreases by 52%.When the longitudinal reinforcement ratio increases from 078%to 15%,the ductility coefficient of the two-limb hoop specimen is approximately 20%higher than that of the three-limb hoop specimen.However,when the reinforcement ratio increases from 15%to 31%,the ductility coefficient of the two-limb hoop specimen is about 25%lower than that of the three-limb hoop specimen.This difference is primarily due to the fact that the three-limb hoop specimen has a lower reinforcement ratio on one side compared to the two-limb hoop specimen with the same reinforcement ratio.