空间刚架结构钢-混结合段疲劳性能试验研究

RESEARCH AND MODEL TEST ON FATIGUE PERFORMANCE OF STEEL-CONCRETE COMPOSITE JOINT IN SPACE RIGID FRAME

为了解空间刚架结构钢-混结合段的疲劳性能,按照几何、物理及边界相似准则设计了1∶2的大比例试验模型,进行了设计寿命期内疲劳加载,测试了疲劳加载过程中钢-混结合段结构主要构件以及焊缝、剪力键的应力及变形情况。试验结果显示:空间刚架结构钢-混结合段在疲劳荷载作用过程中的应力水平较低,应力分布基本无变化,钢与混凝土相对滑移量很小;疲劳荷载作用后钢结构、混凝土结构无表观裂纹,超声波探伤结果表明疲劳荷载作用后钢结构焊缝无超标缺陷;结合段顶部钢与混凝土之间的界面粘结被破坏,但由于剪力键的作用,钢与混凝土的最大相对滑移量为0.036mm;该空间刚架结构钢-混结合段具有良好的疲劳性能。最后从疲劳性能的角度对钢-混结合段的合理构造设计进行了讨论。

Based on the similarity principle of geometry, physics and boundary conditions, a 1 ： 2 scale test model is designed to investigate the fatigue performance of steel-concrete joint section of the space rigid frame. Fatigue load is applied to the test model according to the design serviceability life, and the variations of stress and deformation of main members, weld and shear connectors with loading history are obtained. The results show that the stress of steel-concrete joint is low and the stress distribution has no remarkable variation during fatigue cyclic loading. The relative slippage between steel box and concrete is small. Moreover, there＇s no visible crack on the steel and concrete structure after fatigue test, and the results of ultrasonic inspection show that there＇s no defect found at the weld exceeding code specifications. The interfacial bond between steel and concrete on the top of composite joint is destroyed, but the maximum relative slippage is only 0.036mm due to the effect of shear connectors. The steel-concrete composite joint of the space rigid frame has good fatigue performance. In the end, the reasonable design of steel-concrete composite joint is discussed in the view of fatigue property.