Condition assessment and life cycle costing of concrete and steel footbridges in Kampala

Abstract

The purpose of this study was to perform a condition assessment, determine the life cycle costs of a steel and a concrete footbridge in Kampala and propose the most economical option between the two. Footbridge maintenance is not a priority item on the agenda of different stakeholders in Kampala. This can be evidenced by the poor condition of the footbridges. Defects like cracks, efflorescence and corrosion have developed on concrete footbridges while elements of corrosion, wearing-off of paint and rubbish are associated with the steel footbridge. During the study, the condition assessment of the footbridges was performed to find out the current footbridge condition and the maintenance activities required. We performed a non-destructive test using a Schmidt rebound hammer on the concrete footbridge and a visual inspection on both of the footbridges. The footbridges were ranked according to their current conditions. Steel and concrete footbridges were designed for implementation at Queen’s way road and the life cycle costs of the footbridges determined. Life cycle costing involves; recurring costs which included maintenance costs and non-recurring costs that included design and construction costs. These values were projected by use of economy techniques to future values for a 50-year design life and hence the total life cycle cost was obtained. The results were compared between the steel and concrete footbridges to produce a conclusion on the most economical option. The concrete footbridge had a higher condition rating than the steel footbridge while the steel footbridge had a lower life cycle cost than the concrete footbridge. This therefore led to a conclusion that the steel footbridge is the most economical option of the two footbridges.