用外包钢筋混凝土法加固RC柱的非线性有限元分析

当今国内外建筑物加固改造业发展非常迅速，建筑业重心也正发生着转变，外包钢筋混凝土加固法是一种广泛应用且经济有效的外固方法，本文结合试验手段。利用非线性有限元方法对用外包钢筋混凝土加固柱正截面承载力进行了分析，分析过程中，采用混凝土Chen-Chen三参数模型和均匀硬化法则，采用了八节点等参混凝土单元，三节点等参钢筋单元，引入了双弹簧联结单元模拟钢筋和混凝土之间的粘结滑移，基于大量试验资料，认为新旧混凝土之间具有有效粘结，可以共同工作，编制了加固柱分析有限元程序，计算结果与试验结果符合较好，并初步探讨了国固时核心柱应力水平，外包混凝土的强度比和厚度比等因素对加固柱承载力的影响，为加固柱研究提供了参考。

Non-linear Finite Element Analysis of RC Columns Strengthened with Enclosed Reinforced Concrete

At present, the reinforcement and reconstruction industry is being developed rapidly in the world and the focus of building industry is being transferred gradually. Strengthened with enclosed reinforcement concrete is an economical and efficient method that is being widely used. In this paper, combined with experiment, an analysis was applied on the carrying capacity of strengthened RC columns by non-linear finite element. During the process, the Chen-Chen three-parameter model and the uniform-harden rules were used. Moreover, eight node isoparametric element for concrete and three node isoparametric element for bars were introduced as well as double-spring joint-element was selected to imitateds the bond-slip relation between bars and concrete. Many experimental results show that the new and the formal concrete columns can consider to have sufficient cohesive ability and could be able to work jointly. An analytical program of the strengthened columns is compiled and the calculation results are closed with the test ones. A preliminary discussion on the influences of factors such as initial stress lebel , strength ratio and thickness ratio is provided.