摘要
几何非线性与徐变均为大跨或高耸柔性混凝土结构分析中必须考虑的重要因素,而现有计算方法通常只单独考虑,而未考虑两者的共同作用。基于几何非线性分析的随转坐标法和徐变效应分析的初应变法,该文首先建立三维梁元在随转坐标系下计入初应变效应的几何非线性平衡方程;再利用静力平衡原则,导出三维梁元在结构坐标系下同时考虑几何非线性与徐变的平衡方程,提供了详细的分析流程,编制了相应的非线性计算程序。以某大跨径混合梁斜拉桥混凝土桥塔为例,进行了考虑混凝土徐变效应的几何非线性分析;结果表明,无论是几何非线性还是徐变,单独考虑时得到的内力和位移结果均小于考虑两者共同作用得到的结果,因此在大跨或高耸柔性混凝土结构分析中考虑几何非线性与徐变共同作用是很有必要的。
In analysis of long-span or tall flexible concrete structures, geometric nonlinearity and creep are two important factors, which have usually been taken into consideration separately. However, the coupling of the two factors is of special concern for more accurate calculation. In the present study, based on the co-rotational coordinate method for geometrically nonlinear analysis and the initial strain method for concrete creep, the equilibrium equations for a proposed 3-D beam element was developed, considering both the geometrical nonlinearity and initial strains under the co-rotational coordinate system. By using the principle of static equilibrium, the equilibrium equations were transformed into the global coordinate system and a detailed flow chart of the algorithm was given. Taking into consideration of the effect of creep, the geometrically nonlinear analysis for a concrete tower of a long-span cable-stayed bridge with a hybrid girder was performed for illustration purposes. Results demonstrated that both the internal forces and displacement of the tower when considering the coupling of creep and geometrical nonlinearity were greater than the summation of the results when the two factors were considered separately. It is suggested that the coupling of geometrical nonlinearity and creep is essential for the analysis of large span or tall flexible concrete structures.
出处
《工程力学》
EI
CSCD
北大核心
2015年第6期117-123,共7页
Engineering Mechanics
基金
国家重点基础研究发展计划项目(2011CB013606)
中国博士后基金项目(2014M562154)
湖南省教育厅青年基金项目(14B008)
长沙理工大学土木工程重点学科基金项目(15ZDXK03)
关键词
柔性混凝土结构
三维梁单元
几何非线性
徐变
共同作用
flexible concrete structure
3-D beam element
geometric nonlinearity
creep
combined action
