钢-UHPC组合板群钉效应有限元分析

Finite element analysis on group studs effect of steel-UHPC composite slab

建立考虑栓钉焊缝影响的钢-UHPC组合板推出试件的精细化有限元模型,在验证模型有效性和合理性的基础上,深入分析栓钉与UHPC相互作用机理与试件的受力全过程行为,探究栓钉间距对其抗剪性能的影响.有限元分析结果表明:与无焊缝模型相比,有焊缝模型中的栓钉抗剪承载力与试验值更接近,因此有限元模型中应考虑焊缝的影响;直径和间距对栓钉承载力同样影响显著,且随着栓钉直径增大和间距减小,UHPC板会出现开裂甚至可能破坏.以水平抗剪时栓钉先于UHPC破坏为原则,建议直径d为13 mm的栓钉,其间距不宜小于2.5 d;直径d为16和19 mm的栓钉,其间距不宜小于3.5 d.对于栓钉承载力考虑群钉效应的折减系数η_(G),建议当间距不小于8.0 d时,可取为1.0(不考虑群钉效应);当间距大于建议的最小值且小于8.0 d时,取0.94.

A fine finite element(FE)model of push-out test specimen of steel-UHPC composite slab considering the effect of weld was proposed.Based on the verification of the validity and rationality of above-mentioned model,interaction mechanism between the headed studs and UHPC and the whole loading process of model were studied.Meanwhile,the influence of studs spacing on the stud shear performance was discussed.The analytical results indicated that comparing with the FE model without weld,the calculation results of the FE models considering the weld were closer to the test results,so the weld should be considered in the FE model;the shear bearing capacity of the stud is remarkably influenced by stud diameter and is spacing,and with the increase of the diameter and shorten spacing,the UHPC slab will crack or could even destroy.It is recommended that the spacing of studs should not be less than 2.5 d(diameter)for studs with a diameter of 13 mm,not less than 3.5 d for studs with a diameter of 16 mm or 19 mm,in order to prevent the failure of UHPC before the stud yield.For the reduction factor of the grouped studs effect on the stud shear strength,when the studs spacing is no less than 8.0 d,1.0 is recommended(the effect can be ignored),while when the stud spacing is larger than the recommended values but equal or smaller than 8.0 d,0.94 is recommended.