Design Considerations for Retrofitting of Historic Masonry Structures with Externally Bonded FRP Systems

Abstract

Historic masonry buildings often require structural repair or retrofit to attain a satisfactory level of seismic resistance. This paper analyses the effect of externally bonded fibre-reinforced polymer (FRP) retrofitting systems on the global seismic response of such buildings in order to achieve the fundamental code-based requirements that refer to the structure’s state of damage for a specified limit state. As a case study, a three-storey historic unreinforced masonry (URM) building was selected. The first part of the paper presents an FRP design procedure for determining which vertical structural elements should be retrofitted and to what extent. As a result, six different FRP retrofitting layouts have been selected and analysed with the aid of non-linear static analyses in the second part of the paper. The paper concludes with a cost-feasibility study by introducing a cost-effectiveness index for FRP reinforcement that identifies the effectiveness of an FRP layout by accounting for the amount of retrofitting material used and comparing it with its effectiveness in improving the global seismic resistance.