Optimizing the operating profit of young highways using updated bridge structural capacity

As more private firms participate in public projects aiming to increase their profits by adjusting operational strategies, there has been an increasing demand for structural identification in the operational phase. In this paper, we propose a framework for finding the optimal profit of toll highways over a 5-year part of the operating period. Toll rates are adjusted using the updated safety condition of highway bridges as a constraint on the optimization task. The safety constraint explicitly reflects the requirement on the traffic volume based on the reserve capacity of bridges. The framework includes the following three steps. First, structural identification is carried out to identify parameter values of the bridge involved in the highway project. Then the reserve capacity under the relevant limit state is calculated based on the requirements of bridge design codes. The last step is to investigate the effects of reserve capacity on the optimal operating profit. This framework is applied to a highway flyover project in Singapore. The optimal operating profit based on quantified reserve capacity increases compared to the case without information about reserve capacity. Also, the finding shows that the optimal profit will increase with the increases in values for the reserve capacity until the safety constraint is no longer critical.