Column Strengthening by Using Grooved Laminates
Often there are cases in which a rectangular column has an aspect ratio greater than 3 i.e. the longer side dimension is more than three times the dimension of that of the shorter side. It has been proved that fibre wrapping is most effective with circular column and is less with square and even lesser in rectangular columns. This reduction in effectiveness of fibre wrap increases with the aspect ratio.
The square and rectangular columns are to be given a curvature at the edges. This is done so that the confinement is effective which sharp edges reduce. In case of rectangular columns confinement is further reduced due to different side lengths. If the aspect ratio is very high the column does not show any effect of increase in load carrying capacity achieved by confinement. This effect is taken care by partitioning the longer side into parts so that it behaves like a square column and give good confinement. The carbon fibre Laminates are put in grooved spaces which are 25-40 mm deep depending on what is desirable.
This laminates which are grooved and put inside the column also give extra strength in terms of shear failures.