直角扣件钢管节点抗扭性能试验研究

EXPERIMENTAL RESEARCH ON TORSIONAL PERFORMANCE OF RIGHT-ANGLE COUPLED STEEL PIPE JOINTS

进行了33个直角扣件钢管节点的抗扭性能试验,试验参数主要有:扣件拧紧扭矩的大小、扣件的周转次数、周转加载幅度等。试验结果表明:随着扣件拧紧扭矩的增大,在一次性破坏试验下扣件钢管节点的抗扭刚度也随之增大,但是在多次周转试验下,其刚度增加的幅度则不如一次性破坏试验时明显,而且周转加载幅度越大时,抗扭刚度增加的幅度也越小;扣件周转次数对节点抗扭刚度的影响相对较大,周转次数为15次时,节点抗扭刚度达到最大,周转次数超过35次时,抗扭刚度趋于恒定,同时在该文试验的周转次数范围内,扣件节点的抗扭刚度均大于新扣件一次性试验的抗扭刚度;周转加载幅度越大,则节点的抗扭刚度下降的愈快,试验能周转的次数也愈少。在试验结果的基础上,回归出直角扣件钢管节点扭矩(T)-转角(θ)的关系曲线。由于扣件的节点抗扭刚度,同时受多种因素的相互影响,而工程上也较难界定扣件的周转次数及周转加载幅度等因素,针对以上情况,提出了扣件式钢管支撑体系施工中的几点建议。

Torsional tests on thirty-three right-angle steel pipe couplers were carried out.The test parameters include fastener tightening torques,fastener turnover frequencies and turnover loading amplitudes,etc.The results showed that with the increase of a fastener tightening torque,the torsional stiffness of steel pipe coupled joints increase,and their increase amplitudes under one failure trial are more evident compared to the turnover tests.The fastener tightening torque has little effect on the torsional stiffness under a higher turnover loading amplitude.The fastener turnover frequency has a greater effect on the joint torsional stiffness.When the couple turnover frequency is 15 times,the torsional stiffness of steel pipe joints reach the maximum,and when the turnover frequency is more than 35 times,the torsional stiffness become a constant.The stiffness of turnover couplers is greater than the stiffness under one failure trial in the tests.Under the greater turnover loading amplitude,the turnover frequency becomes less,and the torsional stiffness decrease more rapidly.Based on the test results,the regression constitutive equation for torsion – rotation relationship is obtained.For the complicated influences on the torsional stiffness of couplers and the problems hard to confirm the turnover frequency and loading amplitude,several effective suggestions on the construction of steel pipe supports with couplers are provided.