缓黏结剂固化度对PC梁力学性能影响的有限元分析

Finite element analysis of the influence of retard-bonded sgent curing degree on mechanical properties of the PC beam

为了探明缓黏结剂固化期间缓黏结预应力混凝土梁力学性能的发展规律,对以往试验的缓黏结PC梁进行了弹塑性有限元分析。在有限元分析中,采用ABAQUS软件,用混凝土塑性损伤力学模型来描述混凝土的非线性性能,采用双折线随动强化模型来描述普通钢筋和缓黏结预应力钢筋的材料特性。混凝土采用实体单元C3D8R,普通钢筋骨架和缓黏结预应力钢筋采用二节点的桁架单元T3D2进行模拟。通过与试验PC梁的开裂荷载、极限荷载及荷载-挠度关系曲线的对比分析,探明了缓黏结剂固化期间,钢绞线、缓黏结剂与混凝土之间的传力机理。结果表明:缓黏结剂固化度对梁的初期刚度影响不大,试件梁加载前期,试验结果与有限元分析结果梁的初期刚度基本相同,缓黏结剂固化度对缓黏结PC梁的开裂荷载影响较小,对缓黏结PC梁最大承载力的影响较大,缓黏结PC梁的最大承载力随着缓黏结剂固化度的增大而增大。

In order to investigate the development of mechanical properties of pre-stressed concrete(PC)beams during retard-bonded agent curing degree,finite element analysis of experimental four retard-bonded PC concrete beams is carried out by using ABAQUS software.In these analysis,the plastic damage mechanics model is used to describe the nonlinear behavior of concrete,the Bi-linear constitutive relation is used to describe the material properties of ordinary steel bars and retard-bonded bonded pre-stressed steel bars.And concrete is simulate by the entity element C3D8R,reinforcement steel bars and the retard-bonded pre-stressed tendons is simulated by the truss element with two nodes T3D2.Through comparison with the experimental cracking load,the experimental ultimate load and the experimental load deflection curve,it was verify the transmission mechanism between steel strands,retard-bonded agent and concrete,in agent curing period.The results show that the retard-bonded agent curing degree has little effect on the initial stiffness of the PC beam,the initial stiffness of the experiment was basically the same as that of the finite element analysis.The retard-bonded agent curing degree has a great influence on the maximum bearing capacity of retarded-bonded PC beams,although it has less influence on the cracking load of the retard-bonded PC beam.And the maximum bearing capacity of retarded-bonded PC beams increases with the increase of the retard-bonded agent curing degree.