Civil Engineering Association

Seismic Retrofit of RC Frame Buildings with Masonry Infill Walls: Literature Review and Preliminary Case Study

The purpose of the present study was to investigate possible seismic retrofit options for use in the seismic upgrade of a рeinforced concrete frame building with brick masonry infill walls. The building is typical of a Mediterranean European country (e.g., Greece, Italy, Portugal) and while designed according to the state-of-the-art over 40 years ago, it does not meet the present day seismic design requirements and contains a number of now “well-recognised” seismic design deficiencies and problems such as:
• inadequate beam-column joint details (discontinuous, inadequately anchored bottom beam steel and inadequate shear reinforcement);
• inadequate confinement of columns (stirrups with 90° bends and spacing of 10 bd to 12.5 bd);
• inadequate column splice joint details;
• weak-column strong-beam frame collapse mechanism; and
• brick masonry infill wall interaction with frame response.

The overall aim of this project was to identify the optimal combination of retrofit options that would enable the building to meet the present-day “life-safety” performance criteria for buildings subject to a design magnitude earthquake. As part of this study, a detailed review of the broader literature in the area of seismic rehabilitation was undertaken in conjunction with a preliminary assessment of the building’s seismic capacity. Based on these findings, a number of retrofit schemes will be investigated analytically in order to identify the most suitable course of action.

In the present paper, a summary of that literature review is given, followed by the results of the preliminary assessment of the seismic resistance of the building, and a description of several seismic retrofit scheme options for further detailed study. The effectiveness of the retrofit scheme eventually selected from among the options discussed here will be tested using full-scale pseudo-dynamic tests at the ELSA laboratory of the European Commission’s Joint Research Centre in Ispra, Italy. The results of these detailed analyses and tests will be reported in future publications.