2019 CSCE Annual Conference - Laval (Greater Montreal)

2019 CSCE Annual Conference - Laval (Greater Montreal) Conference


Title
SUSTAINABLE DESIGN OF REINFORCED CONCRETE FLAT-PLATE BUILDINGS BASED ON COST, EMBODIED ENERGY, AND CARBON FOOTPRINT


Author(s)
Mr. Ahmed Noman, Concordia University (Presenter)
Dr. Ashutosh Bagchi, Concordia University, Canada
Dr. Andreas Athienitis
Abstract

Energy is required in all phases of a building life cycle. Embodied energy and carbon emissions of a building are associated with the production, transportation, disposal, and recycling of materials, and during their construction and demolition. A cost-optimized structural design of individual members is obtained by selecting the quantities of materials that satisfy a certain design-code at a minimum cost. For a reinforced concrete structural element, concrete and rebars are optimized for cost. A member thus proportioned for a minimum cost may not always result in lower embodied energy and carbon emission. A different design approach is needed to reduce the embodied energy and carbon to a lower level. In this study, the objective functions for cost, embodied energy, and CO2emission were defined and used in the structural design of a set of RC flat-plate residential buildings with 5-, 10-, and 15-storeys, located in Montreal, Canada. The trade-off between the cost and two other variables was studied. It has been found that some significant reduction in embodied energy and CO2emission is possible for a small increase of the cost for the 5-, 10-, and 15-storey variants. For an optimized solution, the maximum reinforcement ratio of columns has been found to increase with the building height. A slab thickness taken 24% smaller than the minimum thickness specified by CSA 23.3-14 has been found to be most effective in meeting the objective of cost optimization and embodied energy and CO2emission reduction.