钢桁架混凝土组合剪力墙抗震性能试验研究

Experimental study on seismic performance of steel truss and concrete composite shear wall

采用型钢桁架代替钢筋配置在剪力墙中形成钢桁架混凝土组合剪力墙(以下简称"桁架剪力墙"),该剪力墙兼具钢结构延性好和混凝土结构受剪承载力高的优点,且能够克服钢结构耐腐蚀、耐火性能较差的缺点,其通过钢桁架替代钢筋更有利于装配化施工。对4个剪跨比为1.65的钢桁架剪力墙进行拟静力试验,通过试验得到的滞回曲线、骨架曲线和刚度退化曲线等,研究了不同轴压比(0.21和0.26)和不同抗剪键(短钢筋抗剪、短钢筋和栓钉共同抗剪)对剪力墙抗震性能的影响。采用有限元软件ABAQUS对钢桁架剪力墙进行参数分析,进一步考察了轴压比(0.2、0.3和0.4)、桁架竖杆含钢率(1.43%、2.09%和2.71%)和腹杆含钢率(1.37%、2.02%和2.64%)对其受剪性能的影响,并提出剪力墙受剪承载力计算公式。研究结果表明:当轴压比大于0.3时,随着轴压比的提升,剪力墙的受剪承载力有下降的趋势;钢桁架设置抗剪键对于剪力墙的受剪承载力影响不大,但能提高剪力墙的刚度和耗能能力;钢桁架竖杆含钢率对剪力墙受剪承载力有较大提升作用,而桁架腹杆含钢率对剪力墙受剪承载力的提升作用较小。计算钢桁架-混凝土剪力墙的受剪承载力时,可不考虑腹杆受压时平面外的失稳问题。

Steel truss concrete composite shear wall(referred to as"truss shear wall")is formed by replacing the steel bars in the reinforced concrete shear wall with steel truss.The truss shear wall has the advantages of good ductility of steel structure and high shear capacity of concrete structure.It can overcome the shortcomings of steel structure which is not resistant to corrosion and fire.Steel truss instead of reinforcement is more conducive to assembly construction.In order to study the seismic performance of truss shear walls,four shear walls with shear span ratio of 1.65 were tested by quasi-static test.Through the hysteretic curves,skeleton curves and stiffness degradation curves,the effects of different axial compression ratios(0.21 and 0.26)and different steel truss shear keys("short reinforcement"and"short reinforcement and stud")on the seismic performance of shear walls were studied,and the influences of axial compression ratios(0.2,0.3 and 0.4),steel ratios of truss vertical member(1.43%,2.09%and 2.71%)and steel ratios of web member(1.37%,2.02%and 2.64%)on shear capacity of shear walls were further investigated by using finite element software ABAQUS.The calculation formula of shear bearing capacity of shear walls was put forward.The results show that when the axial compression ratio is greater than 0.3,with the increase of axial compression ratio,the shear capacity of shear wall has a downward trend.The shear capacity of shear wall is not affected by the connectors arranged on the steel truss,but the stiffness and energy dissipation capacity of the shear wall can be improved.The steel ratio of steel truss vertical bar has a great effect on the shear capacity of shear wall,while the steel ratio of truss diagonal brace has a little effect on the shear capacity of shear wall.When calculating the shear capacity of steel truss concrete shear wall,the out of plane instability of web members under compression can be ignored.