预应力混凝土结构的应变控制分析

Study on Strain Control of Prestressed Concrete Structure

现在,越来越多的预应力混凝土箱梁桥在腹板处出现裂缝。然而这些裂缝,根据规范规定的在最不利荷载组合作用下是不应该出现的。针对这一现象,试图从应变超限的观点去解释,并对混凝土时变效应导致的应变扩大进行了分析。利用大型有限元软件ANSYS建立变高度混凝土箱梁模型,针对实际工程中竖向预应力容易损失的状况,分析了竖向预应力一定损失度状况下的箱梁腹板应力及应变状况。

Nowadays,more and more pre-stressed concrete box girder bridges crack on the web plate.However these cracks,even under the most disadvantageous load-combination function of the Code,should not appear.In view of this phenomenon,this article adopts the viewpoint that the main factor leading to crack is the strain instead of stress,and the strain expansion out of creep is analyzed.By using the software ANSYS,the stress and strain condition of web plate is analyzed further.