SRC-RC转换柱中钢与混凝土的共同工作

Cooperation of Shape Steel and Concrete in SRC-RC Transfer Column

型钢混凝土-钢筋混凝土(SRC-RC)竖向混合结构是下部采用型钢混凝土(SRC)结构、上部采用钢筋混凝土(RC)结构的特殊结构形式.SRC-RC转换柱是该结构中用于连接下部SRC柱与上部RC柱的转换构件.SRC-RC转换柱由于具有型钢局部存在于柱中下部的特点,钢与混凝土之间的共同工作问题较为突出,导致转换柱产生了特殊的破坏方式.通过对16个SRC-RC转换柱试件和1个钢筋混凝土柱对比试件的低周反复荷载试验,研究了转换柱中钢与混凝土的共同工作,给出了力学模型.研究结果表明:给出的模型可以较好地的说明型钢与混凝土之间的内力传递,并可用于分析转换柱试件的破坏机理;配钢率增大,型钢承担更多的剪力,整个加载过程中混凝土的损伤更为严重;采用型钢截断位置的局部加密和沿柱全高加密两种方式对部分试件采用箍筋加密措施,均取得了较好的效果,增加箍筋的数量可以有效缓解型钢局部存在的不利影响;减小配钢率有利于改善转换柱的滞回性能和变形能力.

Steel reinforced concrete-reinforced concrete （ SRC-RC） vertical hybrid structure is a special form with steel-reinforced concrete （SRC） columns in bottom floors and reinforced concrete （RC） columns in upper floors. SRC-RC transfer columns in the special hybrid structure are used to link the SRC columns below and the RC col -umns above .As shape steel partially exists in SRC-RC transfer columns , the cooperation problem between the shape steel and the concrete is serious , which causes SRC-RC transfer columns to fail in special patterns .In the in-vestigation , by the low-cycle reversed loading experiments of sixteen SRC-RC transfer columns and one reinforced concrete column , the cooperation between the shape steel and the concrete is discussed and a mechanics model is constructed.The results show that （1） the proposed mechanics model can preferably illuminate the transmission of internal force between the shape steel and the concrete and can be used to analyze the failure mechanism of SRC -RC transfer columns;（2） with the increase of the ratio of shape steel area to section area , the shape steel bears more shear force and the damage of the concrete is more serious during the whole loading process ; and （ 3 ） for some specimens , doubling the amount of stirrup at the area where shape steel is discontinuous or doubling the a -mount of stirrup all over the column both can obtain a better effect , and the increment of stirrup can relieve the par-tially-existed adverse effect of shape steel effectively; and （ 4 ） diminishing the ratio of shape steel area to section area helps improve the hysteretic performance and deformation ability of specimens .