梁柱节点剪切变形计算模型基本假定的校核

Calibration of calculation assumptions for beam-column joint shear deformation

现有钢筋混凝土梁柱节点的剪切变形计算模型包含两个基本假定,即矩形的节点核心区发生剪切变形后变为平行四边形,以及4个角点沿矩形原对角线伸长或缩短,且对角线不转动。基于ABAQUS有限元软件,以多组钢筋混凝土梁柱组合体试验结果为依据,对有限元模型的合理性进行了校核,并在此基础上对单调加载和反复加载下钢筋混凝土中间层中节点的受力性能进行了模拟。提取了变形后节点核心区4个角点的坐标数列,根据几何关系直接计算了节点剪切变形,并将其与试验实测结果进行了对比,验证了节点剪切变形计算模型基本假定的合理性。分析结果表明,计算模型采用的平行四边形假定是合理的,但对角线不转动假定存在一定误差。节点对角线转动角度将影响梁端、柱端方向的节点剪切角的计算精度,建议对现有节点剪切变形计算公式进行修正。

The calculation model of the shear deformation of RC beam-column joint includes two basic assumptions.After the shear deformation occurs,the geometric shape of the rectangular joint core will become a parallelogram and the four corner points will elongate or shorten along the original diagonal without rotation.Based on the ABAQUS finite element software,the finite element model of the RC beam-column joint was calibrated according to the test results of RC beam-column subassemblages.The seismic behaviors of the interior beam-column joints under monotonic loading and reversed cyclic loading were analyzed based on the calibrated finite element model.The coordinate data of four corner points of the joint core were extracted to calculate the shear deformation according to the geometrical relationship.The reasonableness of basic assumptions of the calculation model of the shear deformation was analyzed on the basis of comparing the simulation results with the corresponding experimental results.The results show that the parallelogram assumption in the calculation model is reasonable,while the none rotation assumption of diagonal exists considerably errors.The diagonal rotation will directly affect the calculation of the shear deformation angle of the joint at the beam and column surface.The calculation formula of the joint shear deformation should be modified.