MAINTENANCE AND REPLACEMENT PLANNING OF PUBLIC FACILITIES

本研究提出了一种规划模型，以确定在控制结构物理条件的规划范围内，公路结构维护和更换的最优投资时机和投资强度。在现有结构维修和更换的投资决策中，与建造新结构的投资决策不同：(1)投资必须涵盖既有结构维修和更换的投资时机和投资强度等广泛主题。(2)结构的物理状况(劣化状况)取决于其使用年限，并受维修政策的影响。因此，应在模型中对结构劣化进程和维修政策的效果进行定量评估。(3)还应评估与劣化有关的设计物理使用寿命。针对这些问题，提出了一个投资规划模型，首先利用规划模型寻找城市公路桥修复和更换的最优投资时机和投资强度。在此基础上，详细讨论了不同社会经济条件和物理条件下的最优维修策略。其次，利用该模型找出了城市公路路面的最优养护策略。在实际应用中，通过对日本阪神城市公路局路面数据的分析，明确了路面的劣化过程服从马尔可夫随机过程。研究结果表明，该模型对于确定所有公共设施的最优养护策略具有较好的适用性。

The present research proposes a planning model to determine the optimal timing and intensity of investment for maintenance and replacement of highway structures over a planning horizon controlling the structural physical conditions. In the investment policy decisions for maintenance and replacement of existing structure, followings are different from those for construction of new structures:(1) The investment must cover such wide topics as timing and intensity of investment not only for maintenance of existing structure but also for replacement. (2) The physical conditions(deterioration conditions) of structure depend on its age and are effected by maintenance policy. Thus, progress of structural deterioration and effects of maintenance policy should be quantitatively evaluated in the model. (3) The designed physical service life should be also evaluated in relation to the deterioration. Taking account of these issues, a investment planning model is proposed.The planing model is firstly applied to find an optimal timing and intensity of in-vestment for rehabilitation and/or replacement of urban highway bridge. Then, the optimal maintenance policy is discussed in detail for the various socio-economic conditions and physical conditions of the structure. Secondly the model is applied to find the optimal maintenance policy of urban highway pavement. In application the deterioration of pavement is made clear to follow the Markovian stochastic process based on the analysis of pavement data of Hanshin Urban Highway Agency in Japan.The research results show the proposed model is quite applicable to determine an optimal maintenance policy of all the public facilities.