Controlling deflection of long steel I-shaped girder bridge using two V-shaped pre-tensioning cables

Abstract

Despite appropriate design of girder under bending and shear, the deflection of long steel girders usually exceeds the allowable range, and therefore the structural designers encounter challenges in this regard. Considering significant features of the cables, namely, low weight, small cross section, and high tensile strength, they are used in this research so as to control the deflection of long girder bridges, rather than increasing their heights. In this study, theoretical relations are developed to calculate the increase in pre-tensioning force of V-shaped steel cables under external loading as well as the deflection of steel girder bridges with V-shaped cables and different support conditions. To verify the theoretical relations, the steel girder bridge is modeled in the finite element ABAQUS software with different support conditions without cable and with V-shaped cables. The obtained results show that the theoretical relations can appropriately predict the deflection of girder bridge with V-shaped cables and different support conditions. In this study, the effects of the distance from support on the deflection of mid span are studied in both simply supported and fixed supported girder bridge so as to obtain the appropriate distance from support causing the minimum deflection.

摘要

尽管对梁在弯曲和剪切作用下的设计合理,但钢梁的挠度往往超过允许范围,因此结构设计人 员在这方面遇到了挑战。考虑到拉索重量轻、截面小、抗拉强度高等特点,采用拉索来控制长梁桥的 挠度,而不是提高其高度。建立了计算V 形钢索在外荷载作用下的预张力的理论关系式,并计算了V 形索和不同支承条件下钢梁桥的挠度。为验证理论关系,采用ABAQUS 有限元软件,在无索和有V 形索的情况下,对钢梁桥进行有限元建模。结果表明,所建立的理论关系式能够较好地预测V 形索梁 桥在不同支护条件下的挠度。另外,还研究了简支梁桥和固定梁桥中跨间距对跨中挠度的影响,得出 了最小挠度与支座之间的适当距离。