Incremental modal pushover analysis (IMPA) for bridges

In recent years, many research activities were undertaken to develop a reliable and practical analysis procedure to identify the safety level of existing structure. There are many literatures available on the seismic evaluation procedures of buildings using nonlinear static analysis (pushover) instead of performing, as in the well known incremental dynamic analysis (IDA), complex non-linear dynamic analysis (RHA). Conversely, only a few studies are available in literature regarding seismic evaluation of existing bridges, although bridges are strategic infrastructures in every country. The aim of this work is to carry out a seismic evaluation case study for an existing RC bridge, with reinforcement affected by corrosion, using nonlinear static (pushover) analysis. The work starts from an efficient pushover proposal named Incremental Modal Pushover Analysis (IMPA). This procedure has been developed for higher modes sensitive structures; bridge are commonly characterized by a very high participating mass ratio for the higher modes and therefore the application of IMPA to bridges appears as a promising procedure. The procedure, together with some results of the application on one case study, are presented herein.