| This thesis investigates four topics regarding the network optimization system (NOS) of a state highway pavement management system (PMS).; The First topic is to introduce a NOS model with the objective to maximize the network's pavement performance. This NOS model aims to provide an approach simulating a possible scenario in a state DOT by effectively using a given budget in the planning period. Comparison is conducted for the necessary minimum annual budgets for various pavement condition requirements.; The second topic is to quantify the pavement performance using fuzzy set theory. To implement the performance-based NOS model, the performance rating is one of the key factors to be determined. This factor will largely affect the accuracy of the NOS system implementation. Concepts of fuzzy set are applied in this paper to model the performance ratings of the NOS objective function.; The third topic is to extend the NOS system further into a multi-objective optimization system. The goal of the pavement NOS is to use as minimum budget as possible and obtain as maximum performance as we can. As a result, both the pavement performance and the annual maintenance cost, have to be considered simultaneously as the objectives of the optimization system. Multi-objective optimization systems are introduced in this paper to address the problem. This paper implements the NOS problem using the following three methods---Step Method (STEM), Weighted Method and the Method of Constraint. By solving the multi-objective NOS problems, the system can present all the possible circumstances of pavement maintenance costs and pavement performance index values. Then the decision makers will be able to make a reasonable decision by balancing these two objectives. Once a certain level of pavement cost and pavement performance index has been selected, the optimal annual budget allocation plan can also be obtained from the system.; The final topic is to discuss the global network optimization system. This global NOS model is able to optimize the management of multiple categories of pavement networks. |
