单孔PBL剪力连接件疲劳性能试验研究

Experimental study on fatigue behavior of single PBL shear connector

为研究PBL剪力连接件在疲劳荷载作用下的力学性能,完成了2组10个单孔PBL剪力连接件的等幅疲劳推出试验。分析PBL连接件在有、无贯通钢筋两种形式下的疲劳破坏模式,及受剪承载力、剪力-滑移关系受疲劳荷载的影响。通过建立单孔PBL连接件的损伤指标考察其疲劳损伤规律。试验结果表明:无贯通钢筋的PBL剪力连接件的疲劳损伤指标随循环加卸载逐渐趋于稳定,难以发生疲劳破坏;设置贯通钢筋的PBL剪力连接件的疲劳损伤表现为贯通钢筋断裂,PBL剪力连接件的疲劳损伤速度先慢后快,平均残余变形随疲劳荷载循环单调递增,其变化规律符合二次抛物线形式。

The fatigue performance of perfobond shear connector was studied by a series of constant amplitude fatigue tests on ten specimens. The influences of the rebar through the PBL connector on the pattern of fatigue damage were investigated, and the ultimate load-bearing capacities, shear load-slip relationship and residual deformation were measured. A damage function was given to study the fatigue damage development of PBL connector. It shows that the damage factor of PBL connector without rebar remains at a low level, and the specimen can be hardly broken by the cyclic loading. On the contrast, the mechanical behavior of PBL connector with steel can be dramatically influenced by the fatigue loading times and amplitude. A flaw of fatigue damage usually happens at the tension side of steel bar through the hole of PBL plate, and the fatigue damage factor develops slowly at first, then quickly increases with the increase of times of fatigue loading. The residual deformation increases monotonically with fatigue cyclic loading, and exhibits a parabolic relationship as a function of cyclic loading ratio.