DEVELOPMENT OF RESIDUAL STRENGTH EVALUATE METHOD BASED ON ACTUAL CONDITION GRASP OF STRUCTURAL PERFORMANCE BY YEARS PAST FOR MODREN TIMBER BRIDGES

现代木桥的结构刚度经过多年的研究，在对结构刚度进行一次修正后，现代木桥在十年左右的时间里刚度的降低是不会出现的。然而，在20年或更长时间的建造之后，结构刚度会突然下降到约40%。换句话说，很明显，残余强度定量地降低到约60%。通过对现代木桥剩余强度评估的耐久年限估算结果的分析，得出了可以建立可靠性预测耐久年限的养护预防体系的结论。

On the structural rigidity of modern timber bridges by many years past, the rigid reduction of the modern timber bridge past in about ten years will not be seen after a build about the structural rigidity. However, structural rigidity will fall to a suddenly about 40% after a construction in 20 years or more. In other words, it became clear that the residual strength decreased quantitatively to about60%. Furthermore, from the result of estimation of the durable years based on valuation of the residual strength of modern timber bridges, It is acquired the finding that can develop maintenance-preventionsystem which can presume the durable years probabilistically.