Calculation method of initial stiffness of T-stubs involved bolt pretension

摘要

ublishercopyright>? 2019, Editorial Department of Journal of Southeast University. All right reserved.? 2019, Editorial Department of Journal of Southeast University. All right reserved. To reveal more information on the influence of bolt pretension on the initial stiffness of T-stubs, theoretical researches based on the continuous beam model were presented on the calculation method of the initial stiffness of the T-stubs involved bolt pretention considering bending stiffness of bolts or not. A series of equations for predicting the initial stiffness of the T-stubs were derived. The parametric analysis was conducted on the flange thicknesses and locations of the bolts of the T-stubs. Their influences on the initial stiffness of the T-stubs were presented. The research results show that with the increase of the flange thicknesses and the decrease of the distance between the axis of the bolts and the edges of the flanges, the influence of the bending stiffness of the bolts on the initial stiffness of the T-stubs increases. For the mild steel T-stubs with bolt pretension, the calculated results of the initial stiffness considering the bending stiffness of the bolts are nearly 6% higher than those without considering the bending stiffness. But for the hollow structural sections (HSS) T-stubs with bolt pretension, the initial stiffness considering the bending stiffness of the bolts are higher by nearly 30% than those without considering the bending stiffness. Therefore, for the HSS T-stubs with bolt pretension, the bending stiffness of the bolts cannot be neglected when calculating the initial stiffness of the T-stubs.To reveal more information on the influence of bolt pretension on the initial stiffness of T-stubs, theoretical researches based on the continuous beam model were presented on the calculation method of the initial stiffness of the T-stubs involved bolt pretention considering bending stiffness of bolts or not. A series of equations for predicting the initial stiffness of the T-stubs were derived. The parametric analysis was conducted on the flange thicknesses and locations of the bolts of the T-stubs. Their influences on the initial stiffness of the T-stubs were presented. The research results show that with the increase of the flange thicknesses and the decrease of the distance between the axis of the bolts and the edges of the flanges, the influence of the bending stiffness of the bolts on the initial stiffness of the T-stubs increases. For the mild steel T-stubs with bolt pretension, the calculated results of the initial stiffness considering the bending stiffness of the bolts are nearly 6% higher than those without considering the bending stiffness. But for the hollow structural sections (HSS) T-stubs with bolt pretension, the initial stiffness considering the bending stiffness of the bolts are higher by nearly 30% than those without considering the bending stiffness. Therefore, for the HSS T-stubs with bolt pretension, the bending stiffness of the bolts cannot be neglected when calculating the initial stiffness of the T-stubs.