铁路矮塔斜拉T构桥结构设计方法实例研究

Case Study on Structural Design Method of Railway Short Tower Cable-stayed T-shaped Bridge

本文以渝(重庆)黔(黔江)铁路长途河大桥为工程背景,综合考虑桥址地形地质、桥梁跨度、净空及受力特点等要素,提出了主桥采用(132+132) m的矮塔斜拉T构桥型的总体设计方案,并采用数值模拟方法分析了拉索布置范围、索间距对梁部内力、刚度的影响规律。结果表明:(1)斜拉索靠近主塔布置、适当加密索间距有利于减小梁部负弯矩峰值,对梁体受力更为有利;(2)综合考虑拉索对结构受力和梁体刚度的影响,依托工程无索区梁端及塔根无索区分别取为30 m和38 m、索间距按8 m设置。最后,通过开展斜拉索对矮塔斜拉T构桥结构受力影响的分析,探讨了矮塔斜拉T构桥型的适用性。

This paper takes Changtu River Bridge of Chongqing-Qianjiang Railway as a case,advances a scheme of short tower cable-stayed T-bridge with(132+132)m girder considering the topographical and geological conditions of the bridge site,bridge span,clearance,and mechanical characteristics,and analyzes the influence of cable arrangement range and cable spacing on the internal force and stiffness of the girder by numerical simulation.The results show that:(1)the arrangement of stay cables close to the main tower and the appropriately reduced cable spacing is beneficial to reduce the peak value of negative bending moment at the girder,which is more beneficial to the stress of the girder;(2)considering the influence of cables on structural stress and girder stiffness,the cable-free zone at the girder end and tower root of the supporting project is 30 m and 38 m respectively,and the cable spacing is set at 8 m.Finally,the applicability of the short tower cable-stayed T-shaped bridge is discussed by analyzing the influence of cable on the stress of the short tower cable-stayed T-shaped bridge.