某既有铁路混凝土简支梁状态评估试验研究

对服役时间较长的桥梁进行运营状态评估是十分必要的。对一座服役近40a的铁路预应力钢筋混凝土简支梁桥进行了外观检查和现场荷载试验。通过动态和静态测试,测定了该桥的振幅、加速度、自振频率、跨中截面应力、横隔板应力以及跨中静挠度。对数据进行分析认为:从整体看梁的承载能力能满足运营要求,该梁基本处于正常工作状态;桥墩的横向自振频率不满足规范要求,建议加强观测,必要时进行检算或限速,以确保安全。

Test Research into the State Assessment of a Certain Existing Railway Simple-Supported Concrete Girder Bridge

It is extremely necessary to make state assessments of existing bridges that have been in service for a long time,owing to which an observational check and a field loading test were made of a 40-year-old railway simple-supported pre-stressed concrete girder bridge.Through both the static and dynamic tests,the amplitudes of its vibration,acceleration,natural vibration frequencies,stresses of the cross-section of the mid-span,stresses of the diaphragm and the static deflection of the mid-span of the bridge are monitored.After the test results are analyzed,it is found that the bearing capacity of the girder can meet the operation requirements on the whole and the service state of the girder is essentially normal.However,the monitored transversal natural frequency does not meet the requirements of the technical specifications,and therefore,it is highly advisable that some measures,such as strengthening the monitoring work,be taken,and check-calculations be conducted and the running speed be limited when necessary to ensure the safety of the bridge.