大跨度混凝土斜拉桥主梁施工过程应力分析及防裂技术研究

摘要

为研究大跨度混凝土斜拉桥施工阶段主梁裂缝发展规律和控制方法,结合某大跨度混凝土斜拉桥施工阶段主梁裂缝实际观测数据和发展规律,基于有限元理论分析了主梁施工阶段施工缝处关键区域的应力变化规律,并研究了改变普通钢筋配置,添加临时预应力索等裂缝控制措施.结果表明,施工过程中大跨度混凝土斜拉桥主梁节段受力状况易使施工缝处产生裂缝;在施工阶段添加临时预应力索的防裂效果明显.%To study the crack development and the corresponding control methods for main girder of long-span concrete cable-stayed bridge at construction stages, numerical simulations are carried out to analyze constructional stress distribution in critical segmental joints of the main girder and the numerical results are compared to the field measurements of cracks and their development for a long span concrete cable-stayed bridge.Cracking prevention techniques, including changing reinforcement ratios and adding temporary prestressed strands, are also investigated.The numerical results indicate that the constructional stress distribution for the main girders of long span concrete cable-stayed bridges can easily lead to cracking at the segmental joints, and that crack prevention effect from adding temporary prestressed strands is remarkable at construction stages.