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覆土波纹钢板桥涵土与结构相互作用分析及设计方法研究

Soil-Structure Interaction Analysis and Design Method Study of Buried Corrugated Steel Bridges

【作者】 冯芝茂

【导师】 刘保东;

【作者基本信息】 北京交通大学 , 桥梁与隧道工程, 2009, 硕士

【摘要】 覆土波纹钢板桥涵由于受到土体有利的约束作用,从而提高了承载力,在国外已被广泛地应用于公路工程。在我国应用波纹钢板小桥结构。可以发挥其优良的变形适应能力,对预防和解决涵洞因融沉和冻胀而导致的破坏十分有效。在不久的将来,随着对波纹钢板桥涵的进一步研究与改进,此类结构必将成为我国公路建设中的重要结构形式。本文的核心是研究覆土波纹钢板桥涵在恒载与活载作用下的土与结构相互作用,并在此基础上提出对应于我国公路可靠度统一标准与荷载规范的设计方法。本文分别建立了波纹钢板管涵与拱桥的二维非线性数值模型与三维数值模型,将两者的分析结果与实验值做了对比,分析了两种模型的优劣,并且将土与结构相互作用对结构受力性能的影响用数值分析的结果做了说明,另外对于波纹钢板管涵,本文提出了非线性改进的弹性解答,其结果与数值分析的结果和实验值做了对比。在二维非线性数值模型中,采用了土的非线性本构关系,施加于其上的活载经过了等效计算;在三维数值模型中,模型是按波纹的实际形状拼装而成的,土体等效为土压力荷载,没有考虑土与结构的相互作用。最后,通过比较各国现行规范,揭示了现行设计方法的诸多差异与缺陷。结合我国公路可靠度统一标准,提出了波纹钢板桥涵结构对应的极限状态及各自的分项系数。基于国外设计规范的比较结果,综合数值模型、土与结构相互作用理论的分析结论,提出了适用于我国荷载标准与可靠度统一标准的设计方法并给出算例。

【Abstract】 Corrugated steel plate bridges widely built as highway structures of small spans, which are so-called soil-steel bridges, derive their strength from the interaction between the soil and the corrugated steel components of the system.The objective of this paper is to study the soil-structure interaction for soil-steel structures under earth and live loadings and to develop a simplified design procedure for corrugated steel culverts and bridges. The objective is met by conducting an extensive finite element analysis for a circular culvert and arch bridge in Inner Mongolia of China using both two-dimensional nonlinear model and three-dimensional model for varied load cases. The two-dimensional nonlinear model utilizes a nonlinear constitute model of soil material and equivalent two-dimensional live loads based on vehicle loads adopt in Chinese Highway Bridge Design Code to model the soil-structure interaction; The three-dimension model is built up by real shape of corrugations using the equivalent soil pressure loads. The performance of the finite element models is examined by conducting comparisons with both nonlinear improved closed-form elasticity solution and the measured results for the circular culverts and arch bridges.The review of soil-steel structure design practice revealed numerous differences among current method as well as deficiencies. Proposed design limit states were identified and the partial safety factors for loads and resistance was discussed base on the unified standard for reliability design of China. In the end, a simplified design method for soil-steel structure has been developed based on the analysis results of this paper and comparisons work of design practices.

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