| The reversed cyclic loading test of an "as-built" bridge column with details typical of those designed and built (Griezic, 1996) in the Montreal area in the 1960's is reviewed. This test emphasized the inadequate design and detailing used at that time and showed how poorly lap-spliced dowels perform under reversed cyclic loading. A retrofitting technique (Griezic, 1996) that employs an added footing block, which moves the location of expected plastic hinging to the top of the lap splice and adds confinement to the lower portion of the lap splice region, and adds an infilled steel shell to confine the column, is also reviewed.;An alternative retrofit technique suitable for corrosive environments is developed and tested under reversed cyclic loading. This retrofit uses an added footing block and a fibre-reinforced, high performance concrete sleeve containing steel hoops in order to confine the column.;Predictions are made on the responses of each retrofit technique, and these are compared to the experimental results. The response of the alternative retrofit technique is analysed and its performance compared to the "as-built" specimen and the column that was retrofitted with an infilled steel jacket. The alternative retrofit specimen increased the strength of the "as-built" column by 53%, compared to an increase of 74% provided by the infilled steel shell retrofit. The alternative retrofit specimen increased the displacement ductility of the "as-built" column from 3.3 to 10.0, compared to 8.3 achieved by the infilled steel shell retrofit. This retrofit technique dissipated almost as much energy as the specimen with the infilled steel jacket retroprofit, and both retroprofit techniques substantially increased the stiffness of the "as-built" column. |
