FRP seismic retrofit of square hollow seimic bridge piers

Student: S. Peloso
Supervisor: Dr. A. Pavese

 

Abstract

Over the past 20 years, fibre reinforced polymers (FRP) have been increasingly employed in the upgrade and repair of concrete and masonry structures in seismic prone countries, with extensive research programmes being carried out worldwide, focusing primarily on the improvement of the seismic capacity of bridge piers.

However, the majority of such research has not considered the case of square hollow section bridge piers. These are very common in Europe, featuring also a construction date between the ‘50s and ‘70s, when seismic zones were often not recognized, resulting thus in piers designed for gravity loads alone. As a consequence, these bridge piers call now for large strength and ductility enhancements in order to meet the prerequisites of modern earthquake resistant regulations.

In addition, a number of such bridges have been subjected to earthquakes resulting, in some instances, in failure mechanisms due to: shear, combined flexure/shear and insufficient lap splice. It is thus clear that the development of efficient structural intervention methods to be applied in the repair and strengthening of square hollow bridge piers is of great importance and relevance, in particular within the framework of European transport infrastructures.

Within the scope of the current research, quasi-static cyclic tests were performed with increasing levels of drift applied to scaled specimens of FRP retrofitted piers, taking trace of the force-displacement diagram and flexural and shear deformations. Further, the effect of FRP intervention in the level of section confinement, the efficiency of the anchorage, the energy dissipation, the achieved ductility and horizontal strength of the retrofitted piers were all thoroughly scrutinised, through comparison with the response of previously tested specimens without FRP application. Finally, the experimental results were also employed to assess the adequacy of currently available design formulae, calibrated through experiments on solid section piers, in the prediction of the capacity of retrofitted hollow bridge piers.

You may download a digital version of this MSc dissertation here.