Timber bridges play a major role in the distribution of Brazil's agricultural products. Most of these bridges are located on secondary roads, whose maintenance is minimal. This neglect is reflected in the bridges, which usually show signs of degradation, putting their users' safety at risk and restricting the transportation of products and people. Log beams - especially of Eucalyptus - are particularly suitable for the construction of bridges on secondary roads because they are widely available, have a low cost, and possess excellent structural properties. Additionally, log beams are suitable members for bridge spans of 10 to 12m, which are typical of bridges on secondary roads. Bridges with log-concrete composite decks composed of log beams laid along the length of the bridge, covered with a layer of reinforced concrete attached to the beams by means of steel connectors, have been studied and built by Brazilian researchers. These researches aim to provide alternatives for bridge construction, offering cost and safety benefits on these roads. Two case studies are presented here of bridges with log-concrete composite decks, both located in the state of São Paulo, Brazil. Our analysis of the performance of these bridges confirms that the combination of reinforced concrete and timber offers advantages over decks made solely of timber, especially in terms of stiffness and durability.
José Luiz Miotto, MSc, CEng
Carlito Calil Junior, DSc, CEng
Antonio Alves Dias, DSc, CEng