【摘要】 考虑轴压比、剪跨比、配筋率等不同参数的变化,设计一组端部带施工缝的钢筋混凝土柱进行低周反复荷载试验。观察试件的破坏形态并与无缝柱对比,发现施工缝对柱端传力机制和破坏机理均有影响,会造成应力集中,使塑性铰长度变小,沿施工缝的滑移使塑性铰区剪切变形增大。试验中测量了施工缝周围的剪切变形,得到剪力-剪切变形滞回曲线。分析各个参数对剪切滞回曲线的影响,发现轴压比增大使受剪承载力提高而使延性降低;剪跨比减小使剪切变形分量增大,同时使滞回曲线由梭形变为反S形。回归得出二折线骨架曲线的分段计算式,并在综合现有剪切恢复力模型研究成果基础上确定加卸载规则,给出了带施工缝钢筋混凝土柱截面剪切恢复力模型。对带施工缝试件进行数值计算,力-位移滞回曲线的计算结果与试验吻合良好,验证了模型的有效性。更多还原

【Abstract】 A series of reinforced concrete columns with construction joints were tested under cyclic loading.The damage characteristic and force transfer mechanism of critical regions were investigated.The results show that construction joints may cause stress concentration,shortening of the length of plastic hinge,and change of shear transfer mechanism.Factors influencing hysteretic shear curves were analyzed and found the shear strength and ductility increased with the increase of axial load ratio,while the shear distortion increased with the decrease of shear span ratio.A hysteretic shear model was proposed for nonlinear shear response of columns with construction joints subjected to cyclic loading.The model consisted of a primary shear force-shear distortion curve with unloading and reloading branches under cyclic loading.The primary curve was the envelop of shear hysteretic loops obtained from test data.The rules for unloading and reloading branches were established by available acceptable experimental and experiential procedure.To verify the validity of the proposed model,correlation studies of analytical results with experimental results of the load-displacement response of columns with construction joints under static load reversals were conducted.The analytical results generally show very good agreement with experimental results.更多还原