In Chimbarongo, VI region of Chile, is located the San Luis road bridge, built in the year 1930. During last inspections have been detected severe scour in the piers, besides other damages, which have forced the closure of the structure. The strengthening done is through pile-driving. This system supposes a high technical complexity with significant intervention in the structure. In addition, there are new conditions of flow of pure waters that must bear the bridge. All these boundaries and requirements makes possible to study an alternative to this first strengthening proposal through an exchange of the structural typology of the bridge. The main objective of this study is to generate and evaluate this alternative strengthening proposal, consisting on the elimination of the piers of the bridge and later construction of a tied arch, in such a way to modify the structural behavior of the bridge, converting the original deck in the bottom tie of an upper arch and avoiding, in this way, any problem related to the foundation of the piers.