Numerical approach of the steel-concrete bond behavior using pull-out models

ABSTRACT This paper deals with the analysis of monotonic loading behavior in pull-out tests. The main objective is to obtain a reliable numerical model to represent the steel-concrete bond behavior using previously obtained experimental results. The tests were performed in RILEM pull-out specimen using 10 mm steel bar and concrete with compressive strength of 30 MPa. The numerical study used Ansys® software, based on FEM (Finite Elements Method). The numerical simulation adopted non-linear constitutive relationships to represent the behavior of both concrete and steel. A contact surface composed of special finite elements modeled the interface between the concrete and the steel bar, allowing a steel–concrete slip. The numerical analysis performed with variation of the main parameters of the software permitted determining the best ones, and choosing them to obtain a good representation of the bond phenomena. The numerical results had a good agreement with the experimental results. Both linear and non-linear approaches represented the pre-peak behavior, however only the non-linear model gave the best approach for the pull-out force. In addition, the numerical results had shown the simplified model can be used to represent the steel-concrete bond behavior reducing the processing time for current structures analysis.

摘要 本研究针对拉拔试验中的单调加载行为展开分析，核心目标是基于已获取的试验数据，构建能够准确表征钢-混凝土粘结行为的可靠数值模型。本次试验采用国际材料与结构研究实验联合会（RILEM）标准拉拔试件，试件配置为10mm直径钢筋与抗压强度30MPa的混凝土。数值分析部分采用基于有限元法（Finite Elements Method, FEM）的Ansys®软件开展，数值模拟中通过非线性本构关系分别表征混凝土与钢材的力学行为；同时采用由特殊有限单元构成的接触面模拟混凝土与钢筋之间的界面，以实现钢-混凝土间的滑移行为。通过对软件核心参数开展变参分析，确定了最优参数组合，以此实现粘结现象的精准表征。数值模拟结果与试验结果吻合良好：线性与非线性两种建模方式均可表征峰值前的受力行为，但仅非线性模型能够最优拟合拉拔力响应。此外，研究结果表明，采用简化模型表征钢-混凝土粘结行为可有效缩短现有结构分析的计算时长。