加设钢管桁架纵梁改造中承式拱桥悬挂桥道系的应用研究

Research on Strengthening Suspended Deck System for Half-through Arch Bridge by Setting Longitudinal Steel-Tubular Trusses

既有的大量钢管混凝土中下承式拱桥的悬吊桥道系,以横梁为主结构,横梁之间缺乏有效的纵向联系,整体性较差,在车辆作用下的变形和振动较大,抗风险能力也较差。其加固改造是一个重要的课题。以石潭溪大桥为例,对采用吊杆横梁间加设钢管桁架加劲纵梁的加固改造方案,从静力性能、动力性能等方面进行了分析,提出了加固改造的技术方案,对加固改造后的桥梁进行了静动载试验。研究结果表明,对于早期修建的无加劲纵梁的中下承式钢管混凝土拱桥的悬挂桥道系,加设钢管桁架纵梁是一种可行有效的加固改造方案,能有效改善桥道系的车振性能、提高其抗风险能力,且施工简单、造价经济、对交通影响小。

The crossbeams are the main member for suspended deck system of many existed half-through or through arch bridges. The deflection and vibration of the deck are comparably large because of the bad integrity of the crossbeams, which are lack of longitudinal connection. Therefore, it is necessary to carry out research on strengthening of such kind of deck system to improve the risk resistance capacity. Taking Shitanxi Bridge as an example, the strengthening project is proposed by setting longitudinal steel tubular trusses between the crossbeams. The static and dynamic behavior of this bridge is then analyzed. The static and dynamic field test after consolidation shows that the proposed project is reasonable. It is indicated that setting steel tubular truss beams between the crossbeams is effective on improving the dy- namic performance and risk-resistance capacity for the suspended deck system of half-through or through CFST arch bridges without stiffening longitudinal beam. This consolidation method is not only economic and applicable, but also has little influence on traffic.