2019 CSCE Annual Conference - Laval (Greater Montreal) Conference
Dr. Mona Abouhamad, Cairo University (Presenter)
Light (cold-formed) steel framing systems (CFS) have proven to be an efficient alternative to traditional building construction systems in low and mid-rise residential and office buildings due to their high strength-to-weight ratio, ease and speed of construction and high recycled content. In order to evaluate their competitiveness over other construction systems, their life cycle cost must be assessed. The life cycle costs over the building life is widely acknowledged as a better indicator of the value for money than the initial construction costs alone. Most available studies on life cycle cost analysis focus on traditional construction material and systems such using timber, reinforced concrete and hot-rolled steel. There is an absence of detailed scientific research or case studies dealing with the potential environmental benefits of off-site construction, particularly the reduced environmental impact and the savings in embodied energy resulting from waste reduction and the improved efficiency of material usage.
The objective of this study is to perform a life cycle cost analysis of CFS buildings in which walls are sheathed with cement-based boards and floors have thin reinforced concrete slabs. This analysis is used to identify the cost proportion of each stage and also to compare life cycle cost of different building material and construction systems alternatives. Life cycle cost is evaluated as the present value of the total cost of the building and its energy consumption throughout its life; including the costs of planning, design, construction, operations, maintenance and disposal, less any residual value. The analysis is performed based on the methodologies outlined in ASTM E917 and ISO 15686-5 for life cycle costing. The study integrates the results of life cycle energy analysis with life cycle cost of construction, maintenance and end of life. Sensitivity analysis is conducted to identify how variability in the input values; e.g., fluctuations in material prices, affects the results. The developed methodology is applied to a university building constructed at Cairo University using the described structural system. The life cycle cost of the building is compared with the life cost of the same building if it was constructed using traditional hot-rolled steel or reinforced concrete and brick walls.