Payment evaluation method for controlling environmental defilement in road construction projects in Sri Lanka

Abstract

Various attempts have been taken in order to achieve the objective of environmental soundness in road construction activities. Effectiveness of allocating the funds and the due payment for the contractor can create a great influence in achieving such an objective. Thus, this study aims to identify what is the optimum payment evaluation method of contractor’s due payment for controlling environmental defilement in road construction projects. The aforesaid research problem was approached through a multiple case study including three road construction projects in Sri Lanka. Different environmental hazards occurred due to different road construction activities, related hazard mitigation methods, fund allocation for environmental hazard controlling and the associated existing payment methods for contractors could be identified through the data collected by means of semi-structured interviews conducted with the professionals who are involved in the projects having knowledge on both environmental and monetary aspects. Further, direct observations and documentary survey strengthened these findings. Quantitative data was collected from each case through a questionnaire survey and prioritized the payment method under each specific hazard controlling method using Relative Importance Index in terms of effectiveness to identify the optimum payment method to the contractor for controlling environmental hazard. Findings revealed that there are four types of such payment methods available including; payments by unit rate, payments where a provisional sum established in the contract; payments where fixed amounts are assigned in the contract and payments made along with some main work item in the contract which were identified being the optimum method under different hazard controlling methods. These findings would be useful for bidders and estimators at the pre-construction stages to develop more effective modes of payment evaluation and to improve effectiveness in estimation.