摘要
以1座FRP斜拉人行天桥为工程背景,研究了FRP人行天桥的结构设计方法和设计指标。分析了采用工业化生产的大截面FRP拉挤型材斜拉桥的受力性能,发现FRP人行天桥具有较高的承载力安全储备,变形和振动舒适性是结构设计中的主要控制参数;总结了各国规范中对人行天桥变形的要求,结合有限元计算和现场实测结果,建议FRP人行天桥的变形限值为跨度的1/500;总结了各国规范中对人行天桥振动舒适度的要求,分析了频率限值、加速度限值及引起加速度的激励荷载,结合有限元计算和现场实测结果,建议以加速度作为设计控制指标,并给出了用于计算加速度的简化激振模型和计算方法;总结了已有文献中各种桥梁阻尼比的实测结果,建议对单一构件FRP桥的阻尼比取0.008,对多构件FRP桥的阻尼比取0.02。基于建议的设计指标分析了FRP连续梁桥和FRP斜拉桥的极限跨度,对实际的FRP人行天桥进行了有限元分析和现场实测,由于无法满足设计要求,提出了加铺混凝土层的改善方法,通过该方法,使此FRP人行天桥的性能达到了正常使用要求;基于以上研究,提出了FRP人行天桥结构的设计方法和指标要求,通过实际的FRP人行天桥的工程实践,证明其是实用、合理的。结果表明:加铺混凝土面层是一种改善FRP人行天桥结构特性的有效方法。
A tentative FRP cable-stayed footbridge was investigated, in which the design method and design indices of FRP footbridges were studied. Firstly, the analysis of mechanical properties of the FRP footbridge made of large section industrialization pultruded profiles was carried out. It was found that FRP footbridge had the high loading capacity, while the deformation and the vibration comfort were the main controlling parameters for structural design. Furthermore, based on summarizing the deformation limits of the footbridge in domestic and international codes and considering the finite element analysis and the field measurement results, the deflection limit of 1/500 span length for FRP footbridge was proposed. The indices for the pedestrian vibration comfort requirements were also summarized, and the frequency limit, acceleration limit and excitation load were analyzed. Considering the finite element analysis and the field measurement results, it was concluded that the acceleration should be the controlling indicator, and simplified excitation load model and calculation method for acceleration were proposed. After reviewing the variety of damping ratio of real bridge in literature, the damping ratio of FRP footbridge was suggested to take as 0. 008 for single component and 0.02 for multi-component structures. Based on the proposed design indices above, the limit span of continuous beam FRP footbridge and cable stayed FRP footbridge were analyzed. For the cable-stayed FRP footbridge, the results of finite element analysis and field measurement showed that it could not meet the designing requirements. Hence, the improvement of overlaying a concrete layer was proposed. After it, the behaviors of the FRP footbridge met the requirements. All these works made out the design approach and the design indices for FRP footbridges, which were proved to be practical and reasonable through the actual FRP footbridge. Results show that overlaying a concrete layer is an effective method for improving the structural performance of
出处
《建筑科学与工程学报》
CAS
2011年第3期14-22,共9页
Journal of Architecture and Civil Engineering
基金
"十一五"国家科技支撑计划项目(2006BAJ03B07)
科技部国际合作计划项目(2010DFR50400)
教育部长江学者和创新团队发展计划项目(IRT00736)
关键词
FRP人行天桥
舒适度
加速度
蹲伏激励荷载
最大挠度
结构性能
FRP footbridge
comfort
acceleration
crouching excitation load
maximum deflection
structural performance
