Factors affecting the accuracy of pre-tender estimation of road construction in Sri Lanka

Abstract

Within the sphere of construction, the "estimating process" is a significant element due to the lack of financial resources available, and out of the branches of estimating, pre-tender cost estimating of road construction projects requires extensive knOlviedge and expertise. The aim of this research is to assist clients and consultants in improving the predictive ability of the cost estimating of road construction in Sri Lanka. This research has been conducted through a literature review of topics related to the cost estimating process, followed by a questionnaire survey. The analy'?Jng of 59 factors conclude that the main factors affecting the accuracy of pre-tender cost estimation of road construction are: accuracy and reliability of cost information, material (prices / availability / supply / quality / imports), clear and detailed drmvings and specifications, completeness of cost information, designer's experience level. "Spearman's Rank Correlation Coefficient" test was used as a measure of agreement between the three groups of respondents with regard tofactors ranking, and it appears that they are generally in strong agreement. Finally, 15 expert interviews were conducted to identijj the existingpractices of cost estimation of road construction in S riLanka. These conclude that the main existing practices are: comparison with past similar projects based on personal experience, established standards ex. HSR (High2vcrySchedule Rates) and comparison with similar past projects based on documentedfacts The stucly recommended that both clients and consultants give more attention to the cost estimating process and to hire qualified technical staff in order to obtain the accurate estimate and to keep computerized historical data of completedprojects.