重载铁路简支板梁动挠度实时监测技术研究

Research on Real-time Monitoring Technology of Dynamic Deflection of Simply Supported Plate Girders in Heavy-haul Railway

20世纪50年代普通钢筋混凝土低高度板梁为适应平原地区和枢纽站场,以降低线路标高,满足桥下净空为要求而广泛采用。但是随着重载线路荷载等级及频次的大幅提高,桥梁结构面临着静力承载能力和疲劳损伤双重挑战,逐步呈现出不同程度的结构性损伤,表现出挠度增大、横向裂纹开合明显,其中挠度是直接反映结构竖向刚度变化的关键指标。在相同工况条件下,移动荷载作用下的动挠度大于静力荷载作用的挠度,所以研究中小跨径老旧桥梁的动挠度实时监测技术,对保障运输安全有序具有重要意义,同时可为同类型桥梁的检养修提供依据。

In 1950s,the common reinforced concrete low height slab beam was widely used in order to adapt to the plain area and the junction station yard,to reduce the elevation of the line and meet the requirements of the clearance under the bridge.However,with the increase of load grade and frequency of heavy-duty lines,the bridge structure is faced with the double challenges of static bearing capacity and fatigue damage,and gradually presents different degrees of structural damage,such as increasing deflection and obvious opening and closing of transverse cracks.The deflection is a key index that directly reflects the vertical stiffness of the structure.Under the same working conditions,the dynamic deflection under moving load is greater than the deflection under static load.Therefore,the study of real-time dynamic deflection monitoring technology of small and medium-sized span old Bridges is of great significance to ensure the safety and order of transportation,and can provide a basis for the maintenance and repair of similar Bridges.