轻型FRP组合桥梁的方案设计与分析

菜单

摘要随着经济的发展，近些年来对桥梁结构的最大跨度、抗超载能力、抗疲劳能力和长期耐久性等方面提出了更高的要求。FRP作为一种新型高性能结构材料受到了结构工程界的广泛关注，国内外的有关研究机构和工程单位对此开展了大量的研究和实践应用。FRP桥梁与传统桥梁结构相比有着众多优点，如自重轻、架设速度快、抗腐蚀能力强且不透水、抗超载和抗疲劳以及抗震性能好、外表美观、色泽持久、可实现更大跨度等。结合近年来的研究工作，本文对轻型FRP组合桥梁的结构形式、受力性能以及设计计算要点进行了分析和总结。

根据一般桥梁的设计规范和现有FRP桥梁实例,本文设计了一座FRP-钢组合桥梁，对其强度和刚度进行验算、分析。通过调研选取适当的桥面板截面形式，根据国内外规范确定梁体挠度的限值，重点分析了施工中的关键技术及难点。56089

另外还以一座FRP斜拉人行天桥为工程实例，研究了FRP人行天桥的结构设计方法与设计指标。分析了采用大截面FRP拉挤型材的斜拉人行天桥的受力性能，发现FRP人行天桥具有很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；根据各国规范中对人行天桥变形的要求，建议FRP人行天桥的变形限值为跨度的1/500；结合各国规范中对人行天桥振动舒适度的要求，建议用加速度作为设计中的控制指标，并给出了用于计算加速度的简化激振模型和计算方法。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，由于实际的FRP人行天桥无法满足设计要求，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。

毕业论文关键词：组合桥梁；轻质；FRP；桥面板；人行天桥

Abstract

Along with the development of economy, higher requirements have been put forward to some aspects of the bridge structure, such as the maximum span, anti-overload capacity, fatigue resistance and long-term durability. FRP, as a new high-performance structural material, has obtained wide attention from the structural engineering. The domestic and international research institutions and engineering units have carried out extensive research and practical application on it. Compared with the traditional bridge structure, FRP bridges have many advantages, such as light weight, quick erecting, strong corrosion resistance and impervious, high anti-overload capacity, good fatigue resistance, good seismic behavior, beautiful appearance, lasting color and lustre, greater spans, etc. Combining with researches in recent years, we analyze and summarize the structures, mechanical properties as well as design and calculate points of light FRP composite bridges in this paper.

Based on the design specifications of general bridges and examples of the existing FRP bridges, we have designed a FRP-Steel composite bridge model here. Then we make checking calculation and analysis on its strength and stiffness, thus select an appropriate section of the bridge deck through research, determine the limits of beam deflection according to the domestic and international specifications, especially we perform an analysis on the key technology and construction difficulties.

In addition, a FRP cable-stayed pedestrian bridge was investigated as an engineering example, to study the structure design methods and indexes in this paper. The analysis of mechanical properties of the FRP cable-stayed footbridge made of large section pultruded FRP profiles was carried out. It was found that pedestrian bridge had very high loading capacity, the deformation and vibration comfort were the main control parameters for structure design. Based on the deformation limits of the footbridge in domestic and international specifications, we proposed the 1/500 span length as the deflection limit for FRP footbridge. Considering the vibration comfort requirements of the FRP pedestrian bridge in different countries, it was suggested that the acceleration should be the control index，simplified excitation load model and calculation method for acceleration were proposed too. Based on the suggested design indexes above, the limit span of continuous beam FRP bridge and cable-stayed FRP bridge were analyzed. For the actual FRP pedestrian bridge could not meet the design requirements, the improvement method of concrete overlay structure was proposed, through this method, the performance of the FRP footbridge would achieve the normal operation requirements.