Seismic vulnerability and retrofitting of “Gioieni bridge” in Catania using innovative materials

This paper deals with a large series of in situ investigations as well as some modern techniques of retrofitting for maintenance and restoration of road bridges in urban areas. The paper reports the study of the evaluation of the materials degradation and of the seismic vulnerability of the bridge known as "Ponte Gioeni" built in the early 60s. The structural typology of this bridge represents the typical structural architecture adopted in the city of Catania at that time, besides it also plays a key role in the urban road network, so for its historical, architectural and functional importance, now in its 50th anniversary, we have considered it necessary to undertake the process of analysis of the status quo in order to evaluate the possibility of the restoration and retrofitting to modern standards required by structural rules. After a first phase that covered the control of the deterioration of reinforced concrete (obtained by measuring the concrete degree of carbonation, the chromatography of the concrete and the measure of the degree of oxidation of the steel reinforcement by the electrochemical potential, etc.), we proceeded to the determination of the real materials resistance also on the basis of the data obtained from previous investigations in compliance with the new rules. The analysis of seismic vulnerability of the structure was carried out according to new structural Italian codes by means of a 3-D modeling, in order to identify the most deteriorated areas. Then, a series of retrofitting and strengthening technique based on the use of both traditional and innovative materials (PBO, CFRP, etc.) were studied and discussed.