大跨径混凝土箱梁桥剪切开裂及下挠原因

Cause Analysis for Shear Crack and Deflection of Long Span Concrete BoxGirder Bridge

摘要:

从设计角度对大跨径预应力混凝土箱梁桥的剪切开裂及下挠原因进行了分析.采用考虑截面翘曲在内的7自由度空间直梁计算模型和空间梁格计算模型对某工程实例进行了计算比对.结合工程实例,计算分析了箱梁活载剪应力放大系数，探讨了箱梁底板开裂和剪力滞效应对挠度的影响.

关键词:大跨径; 箱梁桥; 翘曲; 剪切开裂; 下挠

Abstract:

The paper presents an analysis of the cause for shear crack and deflection of long span prestressed concrete boxgirder bridge.A comparative study is conducted on the calculation results of a practical project based on 7 freedom space straight beam model considering section warping and space beam grid model. The paper also presents an analysis of the amplification coefficient of shear stresses,and a discussion about the influence on deflection by crack of bottom slab and shear lag effect.

Key words:long span; boxgirder bridge; warping; shear crack; deflection