Economic evaluation of the wooden bridges replacement for steel-reinforced concrete composite bridges in the Balsas-MA rural zones

Abstract

A river is a natural obstacle in the passage between two points. One way to overcome this obstacle is building a bridge that can be made of rock, wood, steel, concrete, or a combination of these materials. In Balsas, Maranhão’s country town, it is common to use wooden bridges to connect rural communities to each other and to the city’s downtown. However, heavy vehicle traffic has led to the collapse of these bridges, causing isolation and disruption to these communities. The study purpose was to economic evaluation of the wooden bridges replacement for steel-reinforced concrete composite bridges in Balsas, as composite structures are more resistant to applied loads when compared to wooden bridges built in the region. Therefore, replacing budgets for wooden bridge were made and compared with composite bridges construction. The results indicated that composite bridges have a higher cost, but, when analyzing the proposition economically, through net present value, internal rate of return, discounted payback, and cost-benefit, it was found that the proposition is economically viable when the wooden bridge service life lasts for one year. Therefore, it can be concluded that replacing the wooden bridge with a composite bridge is necessary for bridges with a higher collapse incidence. Nevertheless, if the problems caused by isolation due to the collapse of the wooden bridge are considered, replacing the wooden bridge with composite bridges is necessary.