EVALUATION OF COST VARIATION IN SUBSTRUCTURAL WORKS OF BUILDINGS (CASE STUDY OF KATSINA MASS HOUSING ABUJA)
Abdulrahman Rilwan Shuaibu& Abdulrahman Hassan Shuaibu2
Department of Quantity Surveying, Federal University of Technology, Minna
2Civil Engineering Department, Federal University of Technology, Minna
Email: ridwanshuayb1@gmail.com & ahas92@yahoo.com
ABSTRACT
No matter how detailed and precise a Bill of Quantities (BOQ) is, variations are inevitable. Information regarding the extent to which these variations affect construction cost are very scanty especially for sub structural works. This research evaluates the cost variation in sub-structural works of building projects (Katsina mass housing estate). Systematic random sampling technique was used and a total of 74 numbers of duplexes was taken as the sample size out of 107. Data were sorted from the BOQ for the project and thorough physical re-measurement of sub-structural works was estimated. Consequently the mean of each sub structural works were calculated from which the percentage cost variation of each item of work in substructure were determined. Sub-structural components which are largely dependent on prices of goods like cement and reinforcement had marginal variation while others which are dependent on ground conditions like back filling, laterite filling had gross variations. Comparing the means for both measured and re-measured costs showed that the difference was significant.