加载速率对屈曲约束支撑性能影响试验研究

Experimental study on the effect of loading rate on the performance of BRB

屈曲约束支撑属于位移相关型阻尼器,简称BRB,具有饱满且稳定的滞回耗能特性,在新建高层建筑和已建结构的抗震加固中得到广泛应用。材性实验表明,钢材强度随着加载速率的提高而增大,因此,推测BRB的性能亦受加载速率的影响。为探究加载速率对BRB性能的影响规律,本文设计了4组不同加载速率的对比试验,发现支撑耗能能力、等效粘滞阻尼比、拉压不平衡系数、疲劳性能等性能参数随加载速率变化而变化。加载速率增大,试件刚度增大,滞回曲线面积增加;承载力先增大后趋于平稳,拉压不平衡系数均有显著的增大趋势。分析得到检测屈曲约束支撑性能参数加载速率建议值,同时提出使支撑稳定耗能的措施。

Buckling restrained braces is a displacement dependent damper,or BRB for short,which has full and stable hysteretic energy dissipation characteristics,and is widely used in seismic reinforcement of new high-rise buildings and existing structures.The strength of steel increases with the increase of the loading rate,so it is speculated that the performance of BRB is also affected by the loading rate.In order to explore the influence law of loading rate on BRB performance,four groups of comparative tests with different loading rates are designed,and it is found that the energy dissipation capacity of support,equivalent viscous damping ratio,unbalance coefficient of tension and pressure,fatigue performance and other performance parameters change with the change of loading rate.With the increase of loading rate,the rigidity of specimen increases and the area of hysteretic curve increases.The bearing capacity increases first and then tends to be stable.The suggested values of load rate for testing buckling restraint bracing performance parameters are obtained and the measures for energy dissipation are proposed.