【摘要】 分析了采用双边箱主梁截面的混凝土斜拉桥张拉横梁平弯预应力束时边箱斜腹板混凝土出现的横桥向裂缝,基于弹性理论分析了这种情况下混凝土主拉应力。假设预应力束的平弯曲线为直线,用直线段上的均布荷载代替预应力束对斜腹板的作用,采用无限大板作用集中力的弹性力学公式,通过对直线段上应力积分和坐标变换,求得了估计这种情况下的斜腹板混凝土主拉应力的公式,并据此提出减小主拉应力的方法。理论分析结果显示,将预应力束的平弯曲线用直线代替产生的误差不超过2%,该公式计算结果与有限元结果及实测数据比较表明,主拉应力的计算误差小于0.2MPa,结果满足工程精度需要,该方法可行。更多还原

【Abstract】 Aimed at the cracks in the concrete inclined web of concrete cable-stayed bridge because of the horizontal curvature of prestressing tendon in transverse beam, the tensile stress was analyzed with elastic theory. This paper assumed the curve of strand as line, used distributed load to replace the action of prestressing tendon on concrete inclined web, based on the elastic mechanics formula of infinite plate with concentrated force acting, derived the simplified formula for calculating the stress of concrete inclined web through integral on line and coordinate switch. The results show that the error of considering the curve of strand as line is less than 2%, through the comparison with the result of FEA(finite element analysis) and experimental data, the error of principal tensile stress is less than 0.2 MPa, which prove that the precision of the method meets engineering calculation requirement, the method is feasible. 2 tabs, 8 figs, 14 refs.更多还原