Cost economics of precast walling systems for multistorey buildings – a case study-based approach

Abstract

Traditional monolithic building construction is labour and time- intensive and usually found in inadequate quality. Rapid urbanization and steadily expanding metropolitan populations need fast and time-saving construction technology, which can be aided using precast construction techniques. Precast construction offers numerous benefits including reduced construction time, minimal labour requirement, less resource wastage and higher quality. Despite the advantages of precast construction technology, Sri Lankan multi-storey building construction still predominantly relies on conventional on-site construction techniques due to a lack of fresh knowledge and less awareness about the benefits. Hence, this study aims to assess the cost- effectiveness and environmental impact of adopting precast concrete walling systems in multi- storey building construction in the Sri Lankan context through a life cycle thinking approach. This paper compares a precast concrete walling system with a conventional Cement Sand Block (CSB) walling system in terms of Life Cycle Cost (LCC) and Life Cycle Assessment (LCA). It evaluates the total impact using Eco-Efficiency Analysis. A case studybased approach was adopted and the LCC was compared using the Net Present Value (NPV) method. The results show that the CSB walling system is more cost-effective than the precast concrete walling system in the long run in the Sri Lankan context. But the Ecoefficiency Index of both walling materials is in the same range according to the percentages they got. Moreover, precast walling system shows considerable time and labour saving with improved quality of construction. Therefore, the findings of this study help to select a walling material for multi-storey building construction from a broader perspective.