简支矩形深受弯箱梁静力性能试验研究  

EXPERIMENTAL STUDY ON STATIC BEHAVIORS OF SIMPLE-SUPPORTED DEEP RECTANGULAR BOX GIRDER

作　　者：黄景华[1,2] 陈朝晖[1,2] 马东升[3] 李观宇 

机构地区：[1]重庆大学土木工程学院,重庆400045 [2]山地城镇建设与新技术教育部重点实验室(重庆大学),重庆400045 [3]华北电力设计院工程有限公司,北京100120 [4]云南省电力设计院,云南昆明650051

出　　处：《工程力学》2012年第A01期46-52,共7页Engineering Mechanics

基　　金：国家重大科技专项"水体污染控制与治理科技重大专项"资助项目(2008ZX07315-001-1)

摘　　要：由于城市土地用途改变,冲沟回填筑路,原架空箱涵被掩埋并承受较大的附加土压力和车辆荷载,荷载工况的改变导致管道结构存在破坏风险。对山地城市排水干管常见的深受弯钢筋混凝土架空箱梁进行了模型静力加载试验,分析了此类箱梁的破坏形式、剪力滞效应和抗剪性能,讨论了现行有关设计规范对于箱涵抗弯承载力计算之不足,并对箱梁进行了非线性有限元模拟分析。研究表明:竖向均布荷载作用下,跨高比接近5的简支矩形深受弯箱梁的最终破坏为弯曲破坏。跨中截面无明显剪力滞现象,开裂前1/4跨截面剪力滞效应较明显,开裂后剪力滞效应逐渐削弱。箍筋作为主要的抗剪部件,在斜裂缝出现后承担着大部分剪力。非线性有限元模拟结果与试验结果吻合较好。对于按简支结构设计的排水箱涵在回填前应进行加固措施,避免排水箱涵过早开裂,影响管道的正常使用。The elevated box girders would bear an additional large soil pressure and a vehicle load because of the backfilling of gulch and road construction caused by the function changes of urban lands. The change of a load case would result in the failure risk of a pipeline structure. The static properties of the reinforced concrete deep elevated box girders commonly used in the urban sewage pipeline system are experimentally analyzed. The failure pattern, shear lag effect and shear behavior of such deep box girders are studied. The shortages in the present design codes for the calculation of bending capacities of the box girders are also discussed. The box girder is simulated by using the non-linear finite element method. It is shown that under the vertical uniformly distributed load, the failure pattern of the simple-supported rectangular deep box girder with a depth-to-span ratio of nearly five is bending failure. The shear lag effect in the mid-span section is non-obvious, while it is more obvious before cracking in a quarter-span section. However, the lag effect is weakened gradually after cracking. The results simulated by the non-linear finite element method show an agreement with the experimental results. In order to avoid the premature cracking which affects the serviceability of a sewage pipeline, reinforcing measures should be carried out before the backfilling to the designed simple-supported sewage pipeline.

关 键 词：钢筋混凝土 箱梁 抗剪性能 剪力滞 非线性有限元 

分 类 号：TU312[建筑科学—结构工程]