摘要
[目的]在桥面拓宽施工过程中,常出现新旧桥连接处纵向开裂、拓宽桥面横向开裂等典型问题,如何通过优化和改进桥面拓宽技术解决这些问题是桥梁工程的一个重要内容.[方法]以国内首座跨海大桥——厦门大桥的桥面拓宽工程为背景,提出了一种加肋钢悬臂支撑-底部钢板组合的桥面拓宽方法.该方法有机结合了钢-混组合梁、正交异性钢悬臂板、底部加固钢板等桥面拓宽加固方法,采用混凝土现浇板作为桥面板、湿接法连接新旧桥梁,然后通过外延加肋钢悬臂构建支撑结构,并兼做现浇桥面混凝土的永久性模板.[结果]厦门大桥桥面拓宽加固工程的三维有限元仿真结果表明,钢悬臂布置间距增大会导致拓宽部分混凝土桥面板的拉应力增加,而设置下部加固钢板对于拓宽桥梁结构的挠度和应力分布影响明显.[结论]通过合理布置钢悬臂支撑结构和底部钢板,可显著减少拓宽部分混凝土纵横向裂缝的产生,改善拓宽后的桥梁的力学性能.相关成果有效支撑了厦门大桥的拓宽加固改造施工,为同类工程提供了有益的参考.
[Objective]The construction of widening bridge decks often encounters several challenging issues,for instance,the longitudinal cracks occurring at the intersections between the new and existing sections of the bridge,and the transverse cracks appearing within the widened portions of the bridge.A proper addressing of these issues by enhancing and refining the methods for widening bridge decks constitutes a highly significant aspect of bridge engineering.Through the improvement and optimization of structural design and construction,it is feasible to ensure the bridge integrity and longevity and thereby consolidate its overall safety and performance.[Methods]Based upon the deck widening project for the first cross-sea bridge in China-Xiamen Bridge,the proposed approach rationally combines the strengths of several deck widening methods,namely,steel-concrete composite beam,orthotropic steel cantilever plate,and the bottom reinforcement plate.According to the proposed methodology,the cast-in-place concrete slab is employed as the bridge deck,and a wet connection is adopted to link the original and added parts of the bridge deck.The bridge widening parts are sustained by successive steel ribbed cantilever supports,which are also severe as the permanent formworks for the cast-in-place bridge deck concrete.Meanwhile,a three-dimensional finite element study conducted on the bridge deck expansion of the China-Xiamen Bridge yields crucial insights into the structural behavior and two reinforcement strategies employed.[Results]The investigation meticulously examines the effects of adjusting the spacing between adjacent steel ribbed cantilever supports on the distribution of tensile stress within the enlarged concrete bridge slab.The results indicate that there is a positive correlation between the layout spacing of the extended steel ribbed cantilever support structure(ranging from 0 to 0.5 meters)and the deflection of the bridge deck,as implies that as the spacing of the steel ribbed cantilever support increases,so does the deflection.In the mean time,the utilization of bottom reinforcement plates bolsters the overall stiffness of the superstructure,thereby facilitating the redistribution of stress within the stressed reinforcement and alleviating the stresses incurred by the construction reinforcement within the bridge.These interventions collectively contribute to enhancing the stress state of the retrofitted bridge.The finite element stress simulation results confirm the substantial safety requirement for the bridge retrofit and testify the efficacy of the proposed strategy.By mitigating tensile stress within the concrete components of the widened section,the proposed approach serves to attenuate the risk of crack initiation and propagation,thereby fortifying the structural integrity and extending the longevity of the bridge.Moreover,the finite element simulation further validates the sufficiency of the integrated reinforcement methodology in fulfilling the prescribed criteria for both stiffness and strength concerning the broader concrete deck slab.This substantiates the structural reliability and pragmatic viability of the proposed bridge deck widening strategy and proves its capability to withstand anticipated loading conditions and meet stringent engineering standards.[Conclusions]On the basis of the widening and reconstruction project of Xiamen Bridge,this work introduces a bridge deck widening strategy as a synthesis of steel ribbed cantilever supports and bottom reinforcement plates.The overall deflection of the bridge after widening,steel reinforcement stress,concrete stress,and steel support system stress are systematically investigated by three-dimensional finite element simulation.The influence of the spacing of the ribbed steel cantilever support arrangement on the stress and deformation distributions is disclosed.The proposed extended ribbed steel cantilever support-bottom reinforcement plate combination support system exhibits lightweight and aesthetically pleasing features.It significantly improves the bearing capacity of the widened bridge deck structure and has been successfully implemented in the bridge deck widening construction of Xiamen Bridge,which also offers valuable insights for similar bridge widening and reconstruction projects.
作者
谭万里
余嘉康
孙庄敬
邓晖
熊子多
梅甘娜
王东东
TAN Wanli;YU Jiakang;SUN Zhuangjing;DENG Hui;XIONG Ziduo;ELENGA France Megane;WANG Dongdong(CCCC First Highway Xiamen Engineering Co.Ltd,Xiamen 361021,China;Fujian Key Laboratory of Digital Simulations for Coastal Civil Engineering,School of Architecture and Civil Engineering,Xiamen University,Xiamen 361005,China;Xiamen Road and Bridge Construction Group Co.Ltd,Xiamen 361000,China)
出处
《厦门大学学报（自然科学版）》
CAS
CSCD
北大核心
2024年第4期743-752,共10页
Journal of Xiamen University：Natural Science
基金
国家自然科学基金(12072302)
福建省自然科学基金(2021J02003)。
关键词
厦门大桥
桥面拓宽
加肋钢悬臂支撑
底部加固钢板
桥面裂缝
Xiamen Bridge
deck widening
steel ribbed cantilever support
bottom reinforcement steel plate
deck crack
