系杆拱桥拱脚连接结构受力性能分析的多尺度有限元建模方法  

MULTI-SCALE FEA MODELING METHOD FOR MECHANICAL BEHAVIOR ANALYSIS OF ARCH FEET ON TIED ARCH BRIDGES

作　　者：周萌[1,2] 宁晓旭 聂建国[1,2] 

机构地区：[1]清华大学土木工程安全与耐久教育部重点实验室,北京100084 [2]清华大学土木工程系,北京100084

出　　处：《工程力学》2015年第11期150-159,共10页Engineering Mechanics

基　　金：国家自然科学基金重点项目(51138007);国家科技支撑计划项目(2011BAJ09B02);清华大学自主科研计划项目(2010Z03078)

摘　　要：拱脚连接结构是系杆拱桥的关键局部结构,构造复杂且局部边界条件不明确,该文引入多尺度有限元建模方法研究其受力性能与传力特征,针对以往研究中采用传统局部精细有限元方法存在的不足,引入弹性边界的概念,将系杆拱桥整桥通过合理的连接方式统一到拱脚连接结构精细模型中以替代局部精细模型中的刚性边界条件假定,并通过全桥精细有限元进行验证。以大连某钢管混凝土系杆拱桥为工程背景,基于提出的系杆拱桥拱脚连接结构多尺度有限元建模方法,建立了多尺度模型。同时,根据传统局部精细及全桥精细有限元建模方法,分别建立了局部精细与全桥精细模型作为对比、验证模型。详细的对比研究表明,局部精细模型分析结果受失真区影响较显著,且失真区范围不能通过本模型定量确定,导致传统建模方法科学性降低、计算结果可信度下降,或通过精细有限元试算、全桥精细有限元检验确定失真区范围,带来繁重的精细有限元建模、计算、数据处理工作。应用弹性边界条件,该文提出的拱脚连接结构多尺度有限元建模方法可以较好地模拟局部结构的复杂边界条件,较精确地预测拱脚连接结构的受力行为,且不受失真区影响,计算结果与全桥精细有限元吻合良好。The arch feet are the key sub-structure of tied arch bridges. In this paper, the multi-scale modeling method is introduced to the mechanical behavior analysis of the arch feet on tied arch bridges. To solve the problem existing in the conventional local-elaborate finite element（FE） model, this research introduces the flexible Boundary Conditions to substitute the hard Boundary Conditions used in the local-elaborate model. By employing the flexible Boundary Conditions, the global scale model of the arch bridge is added to the local-elaborate FE model by means of proper connection methods. Furthermore, the multi-scale modeling method is identified by the global-elaborate method. Based on the proposed multi-scale modeling method, a multi-scale FE model of a concrete-filled-steel-tube arch bridge with a steel truss and tie beams in Dalian city is established using ABAQUS. Simultaneously, a local-elaborate model and a global-elaborate model are established according to the local-elaborate and global-elaborate modeling methods for comparison and identification, respectively. Intensive comparison study demonstrates that the FE analysis result of the local-elaborate model is significantly influenced by the Fuzzy Region, and that the Fuzzy Region cannot be quantitatively determined, leading to unreliable analysis results or large amount of elaborate FE modeling, analyzing and data-processing work. Based on the idea of the flexible Boundary Conditions, the multi-scale modeling method can accurately simulate the complicate boundary conditions of the local sub-structure, and predict the mechanical behaviors of the arch feet without the influence of the Fuzzy Region. The results of the multi-scale model meet well with those of the global-elaborate model.

关 键 词：系杆拱桥 拱脚连接结构 局部精细模型 多尺度模型 全桥精细模型 有限元 

分 类 号：U448.36[建筑科学—桥梁与隧道工程]