Life Cycle Cost Analysis (LCCA) Delivery Model for an Urban Flexible Pavement

摘要

Pavement alternative evaluation is a key aspect in decision making process in transportation system planning, design and delivery. This study examined the Life-Cycle Cost Analysis (LCCA) model for flexible road pavement infrastructure delivery in a developing economy using 1.9 km urban road in Effurun Metropolis, Uvwie Local Government Area of Delta State of Nigeria as a case study. The overview of existing knowledge, the importance and evaluation of LCCA of pavement delivery is done. The Pavement delivery and design data used for this study, which were obtained from the Office of the Ministry of Works, Effurun, Delta State of Nigeria, included soil sub-grade CBR results, water content condition, soil type and grain size distribution, the reports of route investigation, vehicular traffic counts, and previous maintenance, material and market survey reports. The pavement design data previously used for the design and procurement of urban roads in the area were used for the design of three competing pavement alternatives models, viz: Hot Rolled Asphalt (HRA), Interlocking Concrete Block Pavement (ICBP) and a third; Do-nothing scenario pavement alternative. The Bill of Engineering Measurements and Evaluation (BEME) was developed for the designed alternative to compute their Life- Cycle Costs (LCCs) using present worth cost (PWC) method with varying interest rates in MS Excel software spread sheets for a design life of 20 years. Regression modeling for the three scenarios was done with computer software’s (SPSS and MS Excel) packages. The model’s data robustness was determined and found to be between 0.95-0.99. The model’s validity and sensitivity were also carried out. The study indicates a 43.8% cost savings with the ICBP alternative over the HRA option. The Do-nothing alternative is non–aesthetical and costliest due to the maintenance cost of reinstating the road structure. The models have significance value of less than 0.001(F) respectively. The developed LCCA template and model are applicable for investment studies and decision making as well as cost effectiveness assessment of pavement and bridge delivery.