预应力混凝土梁开裂后抗弯刚度试验研究  

Test Study of Flexural Stiffness of Prestressed Concrete Beams with Cracks

作　　者：胡志坚[1] 王云阳[1] 胡钊芳[2] 刘超[1] 代涛[1] 

机构地区：[1]武汉理工大学交通学院,湖北武汉430063 [2]江西省交通运输厅,江西南昌330002

出　　处：《桥梁建设》2012年第5期37-43,共7页Bridge Construction

基　　金：中央高校自主创新专项资金(2010II002);江西省交通科技重大工程专项资金(2010C0035)~~

摘　　要：为研究预应力混凝土桥梁的梁体开裂后抗弯刚度变化规律,通过6片1∶5模型试验梁的开裂试验,系统分析了有粘结和无粘结预应力混凝土试验梁在单调加载和重复加载方式下的跨中挠度及抗弯刚度变化规律。试验结果表明,梁体抗弯刚度变化与加载方式有关,重复加载条件下梁体极限承载力明显小于一次单调加载情况。在将试验数据与现行规范对比研究的基础上,指出现行规范规定对预应力混凝土梁开裂后的抗弯刚度下降规律考虑不足,无法满足在役桥梁的技术状态评估需求,并通过引入跨中弯矩修正系数的方法提出了具体的抗弯刚度修正公式。To study the variation laws of flexural stiffness of the prestressed concrete bridge beams with cracks, the variation laws of the midspan deflection and flexural stiffness of the bonded and unbonded prestressed concrete beams under monolithic and repeated loading were system-atically analyzed through the cracking tests of 6 model beams in scale of 1 ： 5. The results of the tests and analysis show that the variations of the flexural stiffness of the beams are related to the ways of loading. The limited load bearing capacity of the beams under the repeated loading is obviously less than that of the beams under the monolithic loading in one time. On the basis of the comparative study of the test data and the provisions in the current codes, it is pointed out that the decrease law of the flexural stiffness of the prestressed concrete beams with cracks in the pro- visions in the codes is underestimated, the provisions can not cater for the need of assessment of the technical conditions of the prestressed concrete bridges in service and by introduction of the midspan bending moment modification coefficients, the specific modification formula for the flexural stiffness of the beams is thus proposed.

关 键 词：预应力混凝土梁 模型试验 抗弯刚度 极限承载力 

分 类 号：U446.1[建筑科学—桥梁与隧道工程]