跨线连续钢—混组合梁桥负弯矩区抗裂措施设计与研究
Design and research on crack resistance measures in negative moment zone of continuous steel-concrete composite beam bridges
周慧 1成新1
作者信息
- 1. 中交公路规划设计院有限公司,北京 100088
- 折叠
摘要
为改善跨线连续钢—混组合梁桥负弯矩区的受力性能以解决桥面板开裂问题,以深圳某高速改扩建工程4 ×85 m连续钢—混组合梁桥为研究对象.基于有限元法,研究增设预应力筋、支点升降法、后浇成型、微膨胀混凝土以及增大配筋率对负弯矩区桥面板抗裂性能的影响.结果表明:桥面板后浇成型可消除一期恒载引起的桥面板拉应力;支点升降法和预应力筋均能在桥面板中引入预压应力,有效降低桥面板的应力水平;增大配筋率只能减小最大裂缝宽度,当配筋率小于1.2％时,随着截面配筋率的增加,桥面板的最大裂缝宽度迅速减小,当配筋率超过2.4％时,随着截面配筋率的增加,桥面板的最大裂缝宽度减小幅度变小;微膨胀混凝土可有效减小桥面板的拉应力.最后基于工程实际提出了综合抗裂措施,可为后续类似工程设计提供参考.
Abstract
To improve the stress performance in the negative moment zone of continuous steel-concrete composite beam bridges and address the problem of deck slab cracking,we conduct a research based on the design of a 4 ×85 m continuous steel-concrete composite beam bridge in a high-speed expansion project in Shenzhen.Using the finite element method,the study investigates the effects of adding prestressing tendons,support lifting method,post-casting,micro-expansive concrete,and increasing reinforcement ratio on the crack resistance performance of the deck slab in the negative moment zone.The re-sults show that post-casting of the deck slab can eliminate tensile stresses caused by the first-stage permanent load;that both the support lifting method and prestressing tendons can introduce pre-compression stress in the deck slab,effectively reduc-ing the stress level of the deck slab;that increasing the reinforcement ratio can only reduce the maximum crack width,and when the reinforcement ratio is less than 1.2％,the maximum crack width of the deck slab decreases rapidly with the in-crease of the section reinforcement ratio,but when the reinforcement ratio exceeds 2.4％,the reduction in the maximum crack width of the deck slab decreases with the increase of the section reinforcement ratio;that the micro-expansive concrete can effectively reduce the tensile stress in the deck slab.Finally,comprehensive crack resistance measures are proposed based on practical project,which can provide a reference for the design of similar projects in the future.
关键词
连续钢—混组合梁桥/负弯矩区/增设预应力筋/支点升降法/后浇成型/微膨胀混凝土Key words
continuous steel-concrete composite girder bridge/negative bending moment zone/adding prestressed reinforce-ment/fulcrum lifting method/post-pour molding/micro expansion concrete引用本文复制引用
出版年
2024
国家科技期刊平台
NSTL
万方数据