Comparative Analysis of Structural Steel and Reinforced Concrete Construction for Sustainable Development

Abstract

Current discussions on Africa’s Development revolves around positioning itself as an economic hub. Economic report on Africa, 2015 recognizes that there is potential for Africa to experience greater growth than East Asia countries through industrialization. To aid in this industrial growth, there needs to be corresponding construction development in industrial buildings, rail and roads and housing. This development needs to be environmentally, socially, and economically sustainable. Choice of building material accounts for over 80% of the Greenhouse gas emissions during construction. Studies have sought to determine the performance of newer sustainable building materials like cross-laminated timber, recycled-aggregate concrete, alkali-activated concrete and concrete with reduced cement quantities and use of limestone powder in greenhouse gas emission. To do this however, study of conventional construction material has to be done to determine their contribution to global warming. The study therefore sought to identify the most economical, environmentally friendly, and least time-consuming material for construction. The overall objective of the study involved employing structural design principles of a typical Industrial project to determine the most economical, environmentally friendly and most time efficient building material. A cost-benefit analysis, carbon print analysis, and construction time evaluation of structural steel and reinforced concrete were conducted. A comprehensive design approach was developed with two designs of the same structure using the two materials. The methodology had a simple model structure for comparison. It comprised of a portal frame industrial shed of 60m x 20m in plan, and a double volume height of 7.73m. In addition, an overhead crane to account for abnormal loads was considered. This model structure was large enough to consider large-span design complexities. Two target construction materials (structural steel and reinforced concrete) were used to create the model structure. The two design structures were tested under the same loads. Results showed that embedded carbon for concrete was 149,179.85 KgCo2e/kg, and for steel was 167,193.57 KgCo2e/kg. This study demonstrates that concrete is sustainable in terms of embedded carbon emissions. Its universality is undisputed, making it a more sustainable construction material. The bills of quantities show that concrete construction costs Ksh. 21,542,870.00 while Steel construction costs Ksh. 26,903,320.00. The difference is Ksh. 5,360,450.00. Concrete construction therefore costs 19.92% lower, making it cheaper than steel construction.