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为研究钢与混凝土的界面滑移效应对钢-混凝土组合梁基本动力性能的影响程度和规律,进行了5根跨度3.8 m的简支钢-混凝土组合梁的静载和振动模态试验,其中4根采用抗剪栓钉,剪力连接度分别为0.6、0.7、1.0和1.4,另1根采用能提供刚性抗剪连接的开孔钢板连接件。试验结果表明:在静载作用下,随剪力连接度的提高,组合梁的界面滑移减小,抗弯刚度显著增加。竖弯模态试验中,剪力连接度小于等于1.0的3根梁,其前4阶竖向弯曲模态频率与采用开孔钢板抗剪连接件的试验梁相比均有减小,最小减幅为9.8%,最大减幅达26%;剪力连接度为1.4的梁较开孔钢板连接件的试验梁,基频减小了6.1%,第2~4阶自振频率减小幅度均在10%以上,与连接度为0.6的梁相比,其基频增大了13.2%;试验梁的模态阻尼比随着剪力连接度的增大而减小。扭转模态试验中,各阶扭转模态频率差异程度在7%以内,变化规律不明显。由此可见,钢与混凝土板的界面滑移效应对组合梁竖向弯曲自振频率的影响不容忽视,在设计计算中须予以考虑。试验结果可为工程动力分析提供参考。
In order to study the influence degree and law of interfacial slip between steel and concrete on the basic dynamic performance of steel-concrete composite beams, the static and dynamic modes and modal tests of five simple-supported steel-concrete composite beams with a span of 3.8 m were carried out, of which Four shear studs were used, with shear connection degrees of 0.6, 0.7, 1.0 and 1.4, respectively, and the other one with perforated steel plate connections that provide a rigid shear connection. The experimental results show that under static load, with the increase of shear connection, the interfacial slip of the composite beam decreases and the flexural rigidity increases significantly. Vertical bending mode test, the shear connection of less than or equal to 1.0 of the three beams, the first four vertical bending mode frequency and the use of perforated plate shear connection test beam are reduced, the minimum minus The amplitude of 9.8% and the maximum decrease of 26%. The shear frequency of the beam 1.4 was 6.1% less than that of the perforated steel plate and the decrease of the 2nd to 4th natural frequencies At above 10%, the fundamental frequency increases by 13.2% compared with the beam with 0.6 degree of connection. The modal damping ratio of the test beam decreases with the increase of the shear connection degree. In the torsional modal test, the degree of torsional mode frequency difference of each stage is within 7%, and the variation law is not obvious. Thus, the effect of interface slip between steel and concrete slab on the natural frequency of vertical bending of composite beams can not be neglected and must be considered in the design calculation. The test results can provide reference for engineering dynamic analysis.