无黏结内藏钢板支撑剪力墙滞回性能的数值模拟

Numerical simulation of the hysteretic behavior of unbonded steel plate brace encased in reinforced concrete panel

结合无黏结内藏钢板支撑剪力墙的拟静力试验研究,应用ABAQUS程序对其工作机理和滞回性能进行数值模拟分析,并考察支撑与墙板孔壁间的间隙和摩擦力对其受力性能的影响。试验和有限元分析结果均表明,间隙小而均匀且钢筋布置较合理的试件具有很好的延性,支撑墙板滞回曲线饱满稳定。随支撑轴向压力的增大,内藏钢板支撑的微幅弯曲失稳波数也随之渐增。随间隙的增加支撑对墙板的冲剪作用增大。摩擦力使支撑压力沿其轴向分布不均匀,在支撑轴力大的位置其弯曲失稳半波长较短。随摩擦力增大支撑屈服后的切线刚度增大,且在一定间隙范围内,摩擦力使间隙较大的试件的受压屈服后刚度大于小间隙的试件。分析还表明,当支撑与墙板间的间隙尺寸满足本文的建议公式时,可大幅减小支撑对墙板的局部冲剪作用,进一步提高支撑墙板的延性。

Based on experimental studies of unbonded steel plate brace encased in reinforced concrete panel, hereafter referred to as panel of buckling restrained brace （panel BRB）, finite element analysis of the behavior and hysteretic characteristics of panel BRB has been carried out by using the ABAQUS software, with the effects of clearance and friction between the hole of the panel and the brace on the working behavior of panel BRB taken into account. The analysis and test results indicate that the panel BRB specimens with small and uniform clearance as well as desirable reinforcements exhibit good ductility and stable hysteretic behavior. With the increase in compressive force of the core steel brace, the number of small amplitude flexural buckle waves of the brace also increases. The results also reveal that, with the increase of clearance, the punching shear force of the core brace to the panel increases because of the increase in the amplitude of the buckling waves of the brace. Axial force of the compressive brace is variable along its length when friction appears between the brace and the panel, and the length of buckle waves is smaller where the axial force of brace is larger. Meanwhile, the tangent stiffness of panel BRB is enhanced by the friction, and under compression the tangent stiffness of the specimens with larger clearance is larger than that of the specimens with smaller clearance when clearance is within the specified range. In addition, the punching shear force of the brace to the panel can be decreased and therefore the panel BRB may acquire better ductility when size of the clearance is determined with the proposed formula.