基于主梁损伤的预应力混凝土斜拉桥力学性能退化机理

刘继文¹，杨广军¹，姜作仟¹，杨世龙²，宋涛²

1.山东省公路桥梁建设集团有限公司，山东 济南  250021；2.山东交通学院土建交通学院，山东 济南  250357

摘要：为研究车辆及外界因素作用下预应力混凝土斜拉桥主梁力学性能的退化机理，将斜拉索等效为弹性支承，以等效三跨连续梁为基本结构，推导主梁损伤后拉索索力、主梁弯矩及挠度退化规律的解析表达式。研究结果表明：主梁损伤后靠近主梁损伤处的拉索索力增大；主梁损伤后主梁弯矩及挠度变化主要发生在受损跨。算例验证本文给出的主梁损伤后的预应力混凝土斜拉桥力学性能退化理论计算结果的有效性，可用于主梁损伤后斜拉桥主梁力学性能评估。

关键词：预应力混凝土斜拉桥；退化机理；主梁损伤；连续梁

The degradation mechanism of performance of prestressed concrete cable-stayed bridges based on main girder damage

LIU Jiwen¹, YANG Guangjun¹, JIANG Zuoqian¹, YANG Shilong², SONG Tao²

1.Shandong Road & Bridge Construction Group Co., Ltd., Jinan 250021, China;

2.School of Civil Engineering, Shandong Jiaotong University, Jinan 250357, China

Abstract: To study the degradation mechanism of the mechanical performance of the main girder of a prestressed concrete cable-stayed bridge under the action of vehicles and external factors, the cable-stays are equivalent to elastic supports. Using an equivalent three-span continuous beam as the basic structure, the analytical expressions for the degradation laws of cable force, bending moment, and deflection of the main girder after damage are derived. The research results indicate that after damage to the main girder, the cable force near the damaged area of the main girder increases; the changes in bending moment and deflection of the main girder primarily occur in the damaged span. Case studies validate the effectiveness of the theoretical calculation results on the degradation of the mechanical performance of the prestressed concrete cable-stayed bridge after damage to the main girder, which can be used for assessing the mechanical performance of the main girder after damage.

Keywords: prestressed concrete deck cable-stayed bridge; degeneration mechanism; main girder damage; continuous beam