There are huge amounts of emissions associated with construction industry during its different stages from cradle till building demolition. This study presents a methodology that integrates multi-objective optimization and multi-criteria decision making (MCDM) in order to enable construction decision-makers to select the most sustainable construction alternatives. Four objectives functions are investigated, which are: construction time, lifecycle cost, environmental impact and primary energy in order to construct the Pareto front. A novel hybrid MCDM is designed based on seven multi-criteria decision making techniques to select the best solution among the set of the Pareto optimal solutions. Sensitivity analysis is performed in order to determine the most sensitive attribute and construction stages that influence environmental emissions. The analysis illustrates that WSM, COPRAS and TOPSIS provided the best rankings of the alternatives, primary energy is the most sensitive attribute for different MCDM methods. Moreover, PROMETHEE II is the most robust MCDM method..

Construction emissions have become a major concern that has risen extensively in the last few decades. This paper introduces a building information modeling (BIM)-based model to evaluate the environmental and economic consequences of different project alternatives. The model calculates direct, indirect emissions and primary energy for the overall project life cycle. A hybrid fuzzy multi-objective non-dominated sorting genetic algorithm II (NSGA-II) problem is designed to model the uncertainties associated with the quantification of the judging attributes, and consequently to find the most sustainable materials by minimizing the objective functions; project duration, project life cycle cost, project overall emissions and total project primary energy. Finally, TOPSIS is applied to select the most sustainable material for each construction component among the set of Pareto optimal solutions. A case study of an academic building in Saudi Arabia is presented in order to exemplify the practical features of the proposed model.

Many transportation agencies require the condition assessment of concrete bridge decks as part of scheduled maintenance programs. Traditional bridge deck inspection methods include: hammer sounding and chain drag techniques. The interpretation of such techniques' results depends on the operator and may produce highly variable results. Ground Penetrating Radar (GPR) has been extensively used and become an invaluable technique due to its high level of accuracy, being Non-destructive testing (NDT), low cost and simple operation. GPR technique is used for detecting the steel rebars embedded in the concrete, determining the concrete slab thickness, the asphalt layer thickness as well as developing a corrosion map for the steel rebars. This study presents the recap of using GPR technique in inspection of a bridge deck located in ElKobba suburban in Cairo. A clear methodology for the data collection, processing and analysis of collected raw data is presented. Data is first processed, then Numerical amplitude method is used in the analysis. The study also clearly shows how to determine: 1) the slab thickness, 2) asphalt layer thickness, and 3) the arrangement of steel rebar of the slab. Thus, GPR technique can be used to make structural assessment and obtain the structural information without destruction to the element as well as structural checks and analysis can be performed for the bridge decks.