Traditionally, the engineering education is aiming to establish quantifiable, measurable units, and after that comparing those to utilise the unit considered more suitable. When thinking about sustainability of structures, traditional mentality has to be set aside, as comparing different structural systems is becoming a complex task. Choosing different materials for the same reinforced concrete structure has immediate comparable impact on the environment. Reinforced concrete structures are using excessively the limited limestone and other resources and, in the same time, a large quantity of energy for producing the rebar, the clinker and the structural concrete, having negative impact on the environment. Even if reinforced concrete structures are not generally known as the most sustainable solutions for several structural queries, reinforced concrete structural solutions are preferred for most of the situations due to the other advantages presented by these structures. Hence, considering that specific building indispensable for the society, the aim of obtaining sustainable buildings becomes equivalent to decrease their negative impact on the environment while still taking full advantage of their strength. This target can be achieved by judicious choose of the built-in materials. For a given multistorey reinforced concrete frame building, the scope is to establish the concrete and the reinforcing steel classes in such a way that the impact of these materials on the environment to be kept at the lowest possible level. This paper presents a study on an ordinary reinforced concrete frame structure designed using two different concrete classes (C16/20 and C30/37) and two different reinforcing bar classes (PC52 and S500), obtaining four different possibilities for the same solution. Different combinations of built-in materials are resulting different economic and environmental impacts. The environmental impact for the whole life cycle of the studied solutions, using different material qualities, is estimated using Athena Impact Estimator for Buildings, taking into consideration weighted life-cycle analysis indicators (total energy used, the quantity of solid emissions in air and water, the required natural resources consumed – especially the non-renewable ones – the impact owed to the depletion of the natural resources, human health and the impact on the ecosystems). Besides the environmental impact estimation, realisation cost is also evaluated for each structural solution, obtaining a relationship between the cost (as the major decision influencer) and the sustainability of the studied solutions.
Structural sustainability, reinforced concrete sustainability, economy and sustainability, life-cycle analysis, material quality impact, case study
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