不同形式螺栓抗剪键的受剪性能对比分析

In order further improve the shear resistance in the interface of steel-concrete composite beam, a novel shear connector is proposed, namely U-bolt with a large lateral constraint. The shear performance of U-bolts and straight bolt connectors was compared by the push-out tests. The experimental results show that the failure patterns of straight bolt and U-bolt are different. The former is the crusing of concrete around the bolt, while the latter is the cracking of concrete slab with large transverse cracks restricted between U-bolts. When the embedded depth of the bolt increased, the bearing capacity and initial stiffness of the straight bolt shear connector improved obviously, but there is no effect on the peak slip. When the distance between U-bolts is changed, it does not affect the bearing capacity of the U-bolt shear connector but has a certain effect on the initial stiffness and peak slip due to the different friction areas between concrete slab and H-steel. Compared to two straight bolt connectors under the same embedded depth and steel consumption, the bearing capacity of the U-bolt shear connectors improved by 46% and 33.9% respectively, while their initial stiffness increased by 39% and 30.2% respectively. Based on the test results, the prediction method regarding the shear capacity, initial shear stiffness and load-slip model of U-bolt shear connectors were obtained by modifying the Ollgaard model. The experimental results are in good agreement with the predicted results. The research results can provide a reference for the engineering application and follow-up study of U-bolt shear connectors.