The construction can be broadly classified into three main groups. A new construction , a renovation job and routine maintenance of the buildings.
This article explains the various challenges faced before, during and after the renovation work.
Renovation work could be of various types .It could be as simple as the painting works or it could be complicated such as raising further stories on an existing old structure.
Or it could be extending the building or part of it horizontally.
Expansion (horizontal or vertical) is a different game than the new construction on a maiden plot.
The situation becomes more spicy when (after talking with the structural designer of the old building) we realize that during earlier design, there is no provision for the vertical expansion.
This has two aspects. This means either the foundations are not strong enough to carry the extra load due to higher floors and there is no provision of dowel bars in the upper floor columns .
In such a case we may need to provide additional footings to cater the additional loads.It may also be necessary to strengthen the existing columns so as to make them strong enough to carry the extra loads.
Then comes the vital issue of connecting the old concrete with the new concrete.
This issue is also two fold. The old concrete must bond with the new concrete and the reinforcement bars from the old concrete to the new concrerte must have a continuity .
Since there is no structural provision kept during earlier construction, there won’t be any dowel bars left with the columns or beams or slabs.
Dowel bars are the extra reinforcement bars kept during the concrete which shall be used to tie with the new reinforcement bars of the newly laid concrete.
This problem can be solved with Re-bar grouting method.
In this method, holes are drilled in the old concrete and fresh dowel bars are grouted with strong epoxy material.
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