Framework for construction system selection based on life cycle cost and sustainability assessment

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Abstract The objective of this study is to develop a framework for the selection of construction systems of low and medium rise buildings used in residential, office and commercial applications. The construction systems considered are reinforced concrete framing (RC), structural steel framing (SS) and cold-formed steel framing (CFS). The framework is developed in accordance with the relevant guidelines for life cycle analysis and sustainability and is intended to support decision making in the design stage. The system boundary for the study is from cradle-to-grave, including all cost components from construction stage, use stage and disposal stage in addition to possible recycling/reuse options. The developed framework integrates building information modeling, energy simulation modeling and end of life scenarios to calculate and compare life cycle costs and sustainability advantages of construction system alternatives. All future costs are discounted to their present value using the appropriate interest rates. Uncertainties in the input parameters are modeled using realistic probability distributions and then used in a Monte Carlo sensitivity analysis to investigate the impact of changes in the input parameters on the result. Application of the developed system to a university building revealed the following results. The total life cycle cost is nearly the same for RC framing system and CFS framing system, while the life cycle cost of SS framing system is 13.4% more. When the system is credited for possible revenues resulting from early operation and recycling/reuse, the total life cycle cost of the RC framing system and the SS framing system become nearly the same while the life cycle cost of the CFS framing system becomes 22% less. Sensitivity analysis of the results shows that the discount rate has the most effect on the estimated mean cost followed by the inflation rate and the construction cost. The sustainability assessment focuses on calculating the LEED points associated with material recycling/reuse potentials and waste management.