Steel versus Steel-Reinforced Concrete Bridges: Environmental Assessment

Abstract

Bridge material selection has traditionally been based on engineering and economic criteria. With the increasing interest of the public, industry, and government in sustainable development, environmental assessment in construction is becoming more important. However, we need metrics and data on design alternatives for effective decision making. In this paper, we present results of a life cycle inventory analysis of steel and steel-reinforced concrete bridge girders, based on publicly available data. We find that for the initial construction of equivalent designs for a particular location, a steel-reinforced concrete bridge generally has lower environmental effects than a steel bridge. The expected design life of the two types of bridges is influenced by wear and tear, but also by obsolescence. The uncertainty in bridge design life and related data uncertainties make comparisons based on annualized environmental effects difficult. The steel bridges' beneficial reuse and recycling rates may result in lower annualized environmental effects. In particular applications, however, one material might be preferred over the other due to engineering, aesthetic, or economic criteria, regardless of overall environmental effects.