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 negativemoment zone of continuous steel-concrete composite beam bridges

作　　者：周慧 成新 ZHOU Hui;CHENG Xin(CCCC Highway Consultants Co.Ltd.,Beijing 100088,China)

机构地区：[1]中交公路规划设计院有限公司,北京100088

出　　处：《南昌工程学院学报》2024年第4期41-47,共7页Journal of Nanchang Institute of Technology

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。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 results 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 reducing 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 increase 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 

分 类 号：U442.5[建筑科学—桥梁与隧道工程]