塑性铰区采用纤维增强混凝土柱变形能力计算方法研究

Study on calculation method for deformability of reinforced concrete columns with fiber reinforced concrete in plastic hinge region

采用简化的纤维增强混凝土应力-应变关系,根据截面力的平衡方程和截面变形的平截面假定,推导出塑性铰区采用纤维增强混凝土柱不同极限状态时的曲率。根据柱的曲率分布规律,推导出由柱弯曲变形所引起的柱顶水平位移;采用Sezen模型推导出由柱底纵筋与混凝土粘结滑移所引起的柱顶水平位移,再考虑柱剪切变形引起的柱顶水平位移就得到总的柱顶水平位移。与试验结果对比表明,塑性铰区采用纤维增强混凝土柱在开裂荷载、屈服荷载、峰值荷载、极限荷载作用下的位移计算值与试验值吻合较好。

The curvatures of reinforced concrete columns with fiber reinforced concrete in plastic hinge region in different ultimate limit states were derived according to the simplified fiber reinforced concrete stress-strain relationship as well as section force static equilibrium equation and plane cross-section assumption of section deformation. According to the curvature distribution law of the column,the top horizontal displacement caused by the column bending deformation was derived. The Sezen model was used to derive the top horizontal displacement caused by the bond-slip between longitudinal reinforcement and concrete at column bottom. The top horizontal displacement caused by shear deformation was considered as well. Above all,the total horizontal displacement was obtained. Compared with the test results,the calculated displacements under the actions of cracking load,yield load,peak load and ultimate load are in good agreement with the test results when the fiber reinforced concrete is adopted in plastic hinge region of reinforced concrete columns.