不中断交通下连续箱梁桥拼接缝浇筑方式分析

为了探究不中断交通条件下连续箱梁桥拼宽关键技术，本文依托机荷高速改扩建工程，通过现场桥梁的车桥耦合振动测试，得到某连续箱梁桥的最大振动频率为5.62 Hz，最大振动速度为18 mm?s-1。考虑现场车流量的随机性，以安全的原则共设置两种车辆振动环境（5 Hz，25 mm?s-1和10 Hz，50 mm?s-1），并在实验室中测定了不同龄期抗扰动纤维增强混凝土（Fiber Reinforced Cementitious-composite material 50，FRCM50）的弹性模量和抗拉强度。结合现有的施工工艺和新型接缝材料的特点，提出微差浇筑施工工艺。然后，分别分析了采用一次浇筑、分段浇筑和微差浇筑施工工艺时拼宽连续箱梁的受力特点、接缝时变应力、交通组织模式以及经济性，结果表明微差浇筑工艺具有受力合理、施工机械少、经济性好等优点，可指导实际工程施工，具有良好的应用性。

Analysis of Joint Casting Method of Continuous Box Girder Bridge under Uninterrupted Traffic

In this paper, the key technology of continuous box girder bridge widening without interruption of traffic is explored. Based on the reconstruction and expansion project of locomotive-load high-speed, the vehicle-bridge coupling vibration test of the bridge is performed on site. The testing results show that, the maximum vibration frequency of a continuous box girder bridge is 5.62 Hz and the maximum vibration velocity is 18 mm?s-1. Considering the randomness of traffic flow, two vibration environments (5 Hz, 25 mm?s-1; 10 Hz, 50 mm?s-1) are configured according to the safety principle. Besides, the elastic modulus and tensile strength of Fiber Reinforced Cementitious-composite material 50 (FRCM50) at different ages are measured in the laboratory. Combined with the existing construction technology and the characteristics of new joint materials, the differential pouring construction technology is proposed. Then, the stress characteristics, joint time-varying stress, traffic organization and economy of wide continuous box girder under three construction technologies (one-time pouring, sectional pouring and differential pouring) are analyzed. The results show that the differential pouring technology has the advantages of reasonable stress, less construction machinery and good economy, which can guide the actual construction and has good application.