在有限元软件 ABAQUS的分析平台上,以初始应力水平、索垂度和索直径为参数,建立斜腹杆体外预应力加固前后钢筋混凝土简支梁三维实体模型,研究两点对称荷载下试件的弯曲破坏形态、承载力、塑性应变分布、抗弯刚度以及体外索应力增量的变化规律.结果表明,当其它条件不变时,初始应力水平、索垂度和索直径与简支梁加固效果均呈增函数关系,开裂荷载的提高幅度为 30%~150%,屈服荷载的提高幅度为 10%~40%,极限承载力的提高幅度为 10%~50%,梁体屈服前的抗弯刚度提高幅度为 10%~60%;证明斜腹杆体外预应力加固技术能够提高梁的屈服强度、极限承载力和抗弯刚度,对改善钢筋混凝土简支梁的抗裂性能尤为显著.%Taking the initial stress level,cable sag,and cable diameter as parameters,a three-dimensional substantial model of simply supported steel reinforced concrete beams before and after strengthening with externally prestressed tilted webbing rods was established on the analysis platform of the find element software ABAQUS.The bending failure pattern,bearing capacity,distribution of plastic strain,antiflex stiffness and variation rule of increment of external cable stress of the beam sample under two symmetric point-loads were studied.The result shows that when the other parameters are constant,the relation of strengthening result of the simply supported beam to the initial stress level,cable sag,and cable diameter will exhibit as an incremental function,the cracking load raise from 30% to 150%,the yield load raises from 10% to 40%,ultimate bearing capacity raises from 10% to 60%,antiflex stiffness raises from 10% to 50% before yielding of the beam,verifying that this strengthening technique can make the yielding strength,ultimate bearing capacity,and antiflex stiffness of the beam improved.
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