钢筋混凝土墙板内置无粘结钢支撑抗冲切研究

Study on punching shear for unbonded steel brace encased in reinforced concrete panel

摘要:

为了改善钢筋混凝土墙板内置单斜形无粘结钢板支撑中墙板的抗冲切性能,用开孔槽钢来抗冲切,并将钢板支撑端部的加劲肋立放设置．采用拟静力试验研究了构造对试件滞回性能的影响,基于试验结果探讨了墙板的抗冲切设计方法．试验表明:与支撑周围采用加密拉结筋的抗冲切构造相比,采用开孔槽钢可避免墙板局部冲切破坏,墙板局部冲切开裂程度大幅降低;与支撑端部加劲肋平放设置相比,加劲肋立放时可减小加劲肋端墙板与支撑间空隙的宽度,从而减小端部钢板支撑对墙板的冲切作用力;试件最终发生了墙板局部冲切破坏或支撑受拉断裂,破坏前试件滞回曲线饱满稳定;依据墙板可能的冲切破坏模式,给出了抗冲切验算方法．

Abstract:

Perforated channels and upright stiffeners were employed in the diagonal unbonded steel plate brace encased in reinforced concrete panel, referred to as panel buckling restrained brace (panel BRB), to improve the punching shear capacity of panel. Quasi-static tests were carried out to investigate effects of constructional details on the hysteretic behavior of panel BRBs. Punching shear design methods for the panels were examined based on test results. Tests reveal that the perforated channels can avoid the punching shear failure of panel and greatly decrease the punching shear cracks, as compared with the additional steel bars used around the brace. Besides, compared with flat stiffeners, the upright stiffeners used in a brace can decrease the width of gap between the panel and the brace near the tips of stiffeners and therefore decrease the punching shear forces applied to the panel by the ends of brace. Punching shear failure of panel or tension fracture of brace occurred at the end of tests. All specimens exhibited stable hysteretic behavior before the failure of panel BRBs occurred. The punching shear design methods for the panels were proposed based on the possible failure modes of panels.