Cost Model for Unit Rate Pricing of Concrete in Construction Projects

The construction industry is reportedly over reported of construction cost spillover greatly due to cost indeterminacy. The subsisting methods of unit rate pricing in the industry are either determinate on ad.hoc basis (analytical pricing) or predictive (cost modeling). The literature cited in this paper showed that cost models used in the industry are spurious. Most of the models attempts to respond to whole building cost from inception to completion with a single formula. This paper argues that on the basis of the units of measurement of the various building elements, a holistic cost model for pricing a complete building cost is a near impossibility. Rather, cost model on the basis of each work item is idealized. Accordingly, this paper responded by generating a unit rate cost model for concrete Grade C25 (Reinforced concrete containing dense aggregate) in mix ratio 1:2:4 – 20mm Aggregate. This was done by abstracting and decomposing the relevant cost data and using productivity study by time and motion to determine the various outputs for materials and labour. These were subsequently applied as co-factors to the cost data to derive the unit rate cost. The paper concludes that the model enjoys flexibility of further mathematical treatment if any of the variable is constrained and recommends that other work items should be modeled if the cost of a building must be known and this model should be used to justify contractor’s tender for concrete cost.