Effect of column retrofitting on the seismic response of concrete frames

A full-scale exterior beam-column-slab subassemblage was tested under reversed cyclic loading to investigate the influence of retrofitting with steel corner angles and batten plates to increase the column strength. The response of this specimen was compared to two specimens previously constructed and tested at McGill University (Castele, 1988). Each specimen was designed and detailed according to the 1984 CSA A23.3-M84 Standard with a force modification factor, R, of 2.0 (NBCC 1995). The first specimen represented a deficient subassemblage before retrofit. The response of the retrofitted specimen using steel corner angles and batten plates was compared to the response of a specimen retrofitted using reinforced concrete sleeving (tested by Castele, 1988). The test specimens were instrumented to enable detailed strain, load and deflection measurements at critical locations during the testing procedure. The results of the two retrofit specimens provides some insight into the rehabilitation of older structures containing "weak column" or deficiently designed and detailed columns.In addition, three full-scale column specimens were constructed and tested under monotonic axial compression to determine the effectiveness of the two column retrofitting techniques used in the subassemblage specimens. These tests provided a means of assessing the assumptions used in predicting the responses of retrofitted columns