Rehabilitación de puentes del pasado. Una tarea del futuro

Refurbishment of bridges from the past. A task for the future

A procedure for the safety evaluation of existing structures is presented, based on a case study for the assessment and refurbishment of a 70 years old, damaged plain concrete arch bridge. The study emphasises the interest on the planning of the test and inspection programme for the collection of site data and the introduction of this data in the structural calculations. The aim of the collection of site specific data is the reduction of the uncertainty associated with the variables of a Limit State Function expressing structural safety. The influence of this change can not be considered explicitly in a deterministic assessment. To do so, a probabilistic analysis of structural safety is required. In order to estimate the potential benefit of this type of analysis compared to the application of default deterministic models according to current design codes, the site data is used to calibrate updated deterministic models of action effects and resistance, applying reliability methods to a simple structural model. It is clearly shown that acceptable reliability may be verified through a probabilistic analysis, even for bridges that are damaged or deteriorated, thus avoiding the need for strengthening or live load restriction.