Jordan Journal of Civil Engineering

Are Reinforced Concrete Girder Bridges More Economical Than Structural Steel Girder Bridges ? A South African Perspective


Trevor Haas;


This study investigated the cost-effectiveness of steel girders compared with conventional reinforced concrete girders used in bridge construction in South Africa. The investigation considered an existing bridge which required widening as a result of increased traffic flow. The consulting engineers chose two 10 m reinforced concrete girders for the end spans, while two 22 m post-tensioned reinforced concrete girders were used for the central spans. To determine the cost-effectiveness of the consulting engineer’s choice, steel girders were designed for the 10 m and 22m beams based on the relevant South African design codes of practice. The analysis was conducted for both non-composite and composite action between the steel girders and the reinforced concrete bridge deck. Based on the design calculations, a cost comparison was performed. The investigation revealed that steel girders are an economically viable option when off-the-shelf steel sections up to 10m in length are considered. For the 10 m girders, a significant cost saving was achieved for both noncomposite and composite construction compared with reinforced concrete. However, for the 22m spans, the post-tensioned reinforced concrete girders are significantly more cost-effective compared with steel plate girders. Thus, bridge design engineers should consider steel girders as an option during the conceptual design stage for end spans. A survey was also conducted among senior engineering professionals to determine the reason(s) for the apathy towards using structural steel sections as girders in bridge construction in South Africa.


Composite bridges, RC girders, Steel girders, South Africa, Cost analysis