预应力混凝土桥梁收缩与徐变力学变化的数值模拟

Numerical simulation of the component mechanical change of the prestressed concrete bridge due to shrink and creep

用逐步逼近法计算混凝土收缩与徐变引起的构件预应力损失,并用数值模拟构件预应力损失后的力学特性的变化。该法把时间分割为若干时间段,求解各段因收缩、徐变和松弛引起的预应力损失,并叠加求总损失。考虑损失后的预应力,作为构件有限元离散模型力学边界条件施加上去,从此数值求得构件各时的挠度、应力和应变等力学参量,数值结果表明了该法的有效性。

The stepping approach method is used to calculate the component prestressing loss due to the shrink and creep of concrete,and the change of the components in mechanical properties after the loss is simulated numerically. With the time being separated into some periods,the prestressing loss in each period due to shrink,creep and relaxation is calculated,and then the total loss obtained. The remained prestress is considered as the mechanical boundary condition of the finite element discrete model of the components,and the mechanical parameters of the components in each period such as deflection, stress and strain are computed. The numerical results show the effectiveness of the method.