抄録
In Nepal, Division Road Offices (DROs) implement most bridge construction contracts in the Design-Bid-Build (DBB) approach. On the other hand, a new institutional setup called Project Offices (POs) implements a new contracting approach Design–Build (DB). It was expected that using a new approach and institution to execute the bridge projects would lead to a reduction in time and cost overrun, but the actual effect is still unclear. Therefore, the main objective of this research is to evaluate the effectiveness of the DB approach in POs and the DBB approach in DROs management for time and cost overrun risk mitigation in bridge construction works. This research is performed using the Mann-Whitney test for non-parametric samples, cumulative probability density, histogram analysis, and Pearson's correlation analysis. In the Mann-Whitney test, a hypothesis was set for finding the effect of institutional setups and contracting approaches on time and cost overrun. Furthermore, Pearson’s correlation analysis between time and cost overrun in respect of contracting approach and institutional setup was performed. It was found from the Mann-Whitney test that there is a significant difference between the DB contracting approach with POs and DBB contracting approach with DROs management towards time overrun risk minimization. However, there was no significant difference between those two arrangements for cost overrun minimization. The result of the correlation analysis showed a significant relationship between time and cost overrun. Finally, it was concluded that adopting new risk-sharing mechanisms and establishing dedicated institutions have fundamental achievements for improving the implementation performance of infrastructure construction.
