单因素耐久性退化后预应力混凝土简支梁桥的承载力分析

摘要

We chose three key factors ( initial pre-stress, strength of concrete at the room temperature and freeze-thaw cycles ) affecting the durability of concrete to analyze the capacity of prestressed concrete simply supported beam bridge by the fi -nite element methods .The deflection of simply supported beam has the same variation with the initial pre-stress, and the effective prestress of strand has the opposite change with the max value of deflection .At the room temperature , the strain of concrete at the mid-span of the bridge decreases first , and then increases .In the freeze-thaw cycles, with increasing of the load, the strain decreases gradually .The strain increases with number increase of freeze-thaw cycles.%从影响预应力混凝土简支梁桥耐久性能的因素中，选取3个因素（初始预应力、室温循环下混凝土强度、冻融循环下混凝土强度），运用有限元单元法对预应力混凝土简支梁桥的承载力进行分析。结果表明：初始预应力越大，简支梁的挠度也就越大；钢绞线的有效预应力越大，挠度的变化最大值越小。在室温环境下，随着使用时间的递增，简支梁梁底跨中混凝土应变呈现先减小后增大的趋势。在冻融循环下，随着荷载的增大，同一冻融循环作用下的跨中梁底混凝土的应变逐渐减小，混凝土的应变值随着冻融次数的增加而变大。