角钢塔连接螺栓考虑预紧力的拉剪计算方法研究

Research on Calculation Method of Connecting Bolts Used in Angle Steel Tower under Tension and Shear Action with Pre tightening Force

摘要:

角钢塔普通螺栓施工过程中规定了其施工紧固扭矩的下限值，但在抗剪设计时没有考虑施工紧固扭矩所产生的预紧力对其抗剪承载力的影响，计算表明目前的紧固扭矩值会使得设计偏于不安全。结合钢结构基本原理推导了输电塔普通受剪螺栓在预紧力作用下的抗剪剩余承载力比的计算方法，并结合精细化数值模拟论证了预紧力对普通螺栓抗剪承载力的影响。研究表明，预紧力越大，螺栓的抗剪承载力削弱越明显，近似呈二次抛物线关系；最终依据预紧力和抗剪承载力之间的关系，推荐了输电塔普通抗剪螺栓的紧固扭矩值，为工程设计提供了设计依据。

Abstract:

During the construction of angle steel towers, the lower limit value of tightening torque of bolts is specified, but the influence on its shear bearing capacitycaused by tightening torque is not considered. The calculation shows that the current tightening torque value will reduce the shear bearing capacity. Combined with the basic principle of steel structure, the calculation method of residual shear bearing capacity ratio of common shearing bolts under pre tightening force is deduced,which is proved byrefined numerical simulation. The research shows that the larger the pre tightening force is, the lower the shear bearing capacity is, which is approximate quadratic parabolic relationship. Finally, according to the relationship between pretightening force and shear bearing capacity, the tightening torque value of common shearing bolts for transmission towers is recommended, whichprovides a referenced for the project design.