Modelling bonding failure effects in deteriorated concrete elements of bridges

Nowadays, the seismic study of corroded reinforced concrete elements is a matter of increasing concern, in particular as regards links such as bridges in infrastructural networks. As the first step in an ongoing research, a prestressed concrete bridge overpass (continuous two spans with one central pier between the bents) was selected to perform response spectrum seismic analyses considering corrosion degradation. This was based on the development of a finite element model of the structure and allowed the assessment of the degrading seismic capacity of the reinforced concrete bridge pier at different periods caused by general and pitting corrosion. For this purpose, corrosion models from existing literature were used. An unchecked factor of this first research step is that corrosion can also affect bonding between the longitudinal reinforcing bars and concrete, thus increasingly reducing ductility and safety performance. Moreover, in a corroded structure bond strength and confinement capacity can also decrease due to the transverse reinforcement area loss, and concrete cover cracking and spalling. The new step developed in this work focuses on the bonding failure effects due to corrosion processes and how this affects the seismic performance of the deteriorated pier. The analysis is based on the introduction and validation of an empirical model for the assessment of the remaining bonding in corroded concrete elements with respect to experimental results.