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服役年限较长的公路桥梁往往会出现混凝土开裂、钢筋锈蚀、预应力缺损等病害而导致梁体刚度衰减,针对梁体的实际刚度分布状况识别问题,根据材料力学及数值分析相关理论,以梁式结构为例结合位移互等定理推导梁体各区段的实际刚度分布公式。建立三轴车辆与单位荷载在移动过桥时的跨中挠度曲线之间的转换关系,进而凭借三轴车辆低速行驶过桥时采集的跨中挠度时程曲线即可推导梁体实际刚度分布状况,分析全桥病害分布及损伤程度。根据该算法编制配套计算软件,通过桥梁刚度分布识别的算例验证了文中方法的可行性。结果表明,由于损伤原因及程度各不相同,梁体实际刚度分布沿纵向变化较大,不宜采用全梁整体刚度作为桥梁损伤评判标准;文中算法得到的全梁实际刚度分布与实际受损情况吻合良好,该方法可快速、真实、可靠地反映在役桥梁整体损伤状况、锁定损伤范围并估算损伤程度。
The highway bridges with long service life tend to have the rigidity decay caused by concrete cracking, steel corrosion, prestressed defects and other diseases. According to the theory of material mechanics and numerical analysis, For example, the actual stiffness distribution formula of each section of the beam body is deduced by combining the displacement equal reciprocal theorem. The relationship between the mid-span deflection curve of the three-axle vehicle and the unit load during moving across the bridge is established, and then the actual stiffness distribution of the beam body can be deduced with the mid-span deflection time history curve acquired when the three-axle vehicle passes through the bridge at a low speed , Analyze the distribution and damage of the whole bridge disease. According to the algorithm, the compiling software is compiled and the feasibility of the method in this paper is verified by the example of bridge stiffness distribution identification. The results show that due to the different causes and degrees of damage, the actual stiffness distribution of the beam changes greatly along the longitudinal direction. Therefore, it is not appropriate to use the overall stiffness of the whole beam as the criteria for evaluating the damage of the bridge. The actual stiffness distribution of the whole beam obtained in this paper agrees well with the actual damage Good, the method can quickly, truly and reliably reflect the overall damage status of an existing bridge, lock the damage range and estimate the degree of damage.