The use of carbon fibre reinforced polymer (CFRP) wrapping to strengthen existing cracked masonry columns was investigated experimentally. The study was aimed at quantifying the increase in strength that can be achieved and assessing the effect of column size on the strength increase. Eighteen columns were tested, with three different square cross-sectional sizes (290 mm × 290 mm, 390 mm × 390 mm, 490 mm × 490 mm) and two different types of clay masonry unit. Six columns were constructed in each size, two columns using unit type 1 and four columns using unit type 2. Strengthening was achieved by wrapping the square section columns directly with a single-layer CFRP laminate or by wrapping the columns after first casting a circular concrete jacket around the column. The latter treatment was applied to two of the small-sized columns and two of the intermediate-sized columns. All other square section columns were wrapped directly. Significant strength increases were achieved, particularly when the columns were provided with the cylindrical concrete jacket. These preliminary tests indicate that the use of CFRP wrapping is an effective technique for rehabilitating damaged masonry columns. Decisive conclusions could not be made regarding the effect of column size (cross-sectional area) on the strength increase achieved. Further tests together with nonlinear finite element modelling aimed at duplicating the experimental observations would greatly enhance the information provided by the current tests.
Canadian Journal Of Civil Engineering Vol. 30, Issue 4, p. 734-744