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Five full-scale reinforced concrete wall specimens with openings typical of the first story backside exterior walls of row houses in Taiwan were tested using lateral cyclic loading to study their seismic behavior. The effects of location and size of the window opening were studied. Test results showed that the wall with the window opening on the side of the wall web showed a higher average lateral strength than that with the opening placed around the center of the wall web. The increase of the opening length reduced more the lateral strength than the increase of the opening height. A critical wall segment tended to show a lower lateral strength when the edge of the segment is bordered by a door than by a boundary column. To estimate the lateral strength of the wall specimens, a detailed and three simplified models are proposed. Comparison with the test results shows that ignoring variation in the axial force among the wall segments and columns does not change the average prediction but increases the scatter of prediction. Simply summing the lateral strengths of all the wall segments and columns together further increases the scatter and greatly reduces the degree of conservatism. Summing the lateral strengths of all the web segments requires the least computational effort but greatly increases the degree of conservatism.

An innovative seismic retrofit method was proposed to address the weak first-story issue of reinforced concrete row houses in Taiwan. The proposed method is to turn as-built rectangular columns to L- and T-columns by adding flanges in the weak direction of as-built rectangular columns to strengthen their seismic capacities. The longitudinal reinforcement in the retrofit part of the retrofitted column is not continuous into the beam and foundation above and below the column to ease construction difficulty associated with post-installation of such reinforcement. Large-scale L- and T-columns retrofitted from rectangular columns with the proposed retrofit method were tested in this research using lateral cyclic loading. Test results showed that the retrofitted columns exhibited ductile, flexural dominated behavior. As compared with the original rectangular columns, the proposed retrofit method was effective in increasing the lateral strength of the column. Due to the discontinuity of the longitudinal reinforcement, the retrofitted columns showed lower lateral strengths but less damage and higher ductility than the counterpart monolithic columns. A pushover analysis model was developed for the proposed retrofitted column that accounts for the effects of discontinuity of longitudinal reinforcement in the retrofit part. Comparison of pushover analysis and test results showed that the pushover model generally captured well the force-displacement behavior of the retrofitted columns.