城市曲线梁桥爬移现象及解决措施研究

STUDY ON “CREEPING” PHENOMENON OF CURVED CONTINUOUS GIRDER BRIDGES

曲线梁桥因其自身特点,易产生爬移现象,既影响行车舒适性,又危害桥梁结构安全。该文首先回顾了影响爬移的重要因素,然后以北京某曲线桥梁为背景,建立了数值模型,探讨了恒载、活载、混凝土收缩徐变、温度、预应力等荷载作用下结构的受力特点,与实际桥梁检测结果对比,探讨了桥梁爬移形成的主要原因。此后探讨了缓解曲线桥梁爬移的主要思路,力图通过合理设计支承形式、合理设置支座预偏心、支座形式优化等方式缓解曲线桥的爬移效果。该文研究表明:合理设置支座预偏心、支承形式优化适用于车流量小,半径小的曲线匝道桥。支座形式优化适用于车流量大,曲率半径大,抗扭能力更强的曲线梁桥。新建曲线梁桥在适当条件下,单独或综合使用以上三种技术措施,可以有效预防爬移病害的发生。

Because of structural features, creeping diseases can be easily produced in curved bridges. Creeping diseases will reduce driving comfort and endanger structural safety. The existing research showed that the factors of creeping phenomenon had been analyzed. Taking an overpass bridge as an example, the features of radial displacement were analyzed under the effects such as dead loads, live loads, concrete shrinkage and creep, temperature, prestress, and so on. The influences of supporting form, bearing eccentricity, and bearing form on creeping, were also discussed. The study shows that supporting form and bearing eccentricity optimization method can be used when small traffic and curvature radius were applied in curved bridges. The bearing form optimization is applicable when heavy traffic, large curvature radius and torsional stiffnesses are shown in the curved bridges. When doing optimization design for a new curved bridge, the above three method and their mixed forms can all be applied for preventing creeping diseases.