Repair and Rehabilitation of a Residential Building at Nile River in Cairo

Five floors were added to a six storey building during its construction without carrying out necessary structural calculations. When such calculations were later performed they revealed that both the spread footing foundation and many columns were unsafe. The contact pressure beneath footings exceeded the allowable soil pressure. The repair method described in this paper depended on disregarding the spread footing foundation and constructing a new deep foundation system for the existing building. This consisted of end bearing bored piles drilled and cast in the voids between the footings using a special low rise rig. The piles were connected to a rigid reinforced concrete raft located above the footings. The raft in turn was connected to the ground floor columns by means of reinforced concrete jackets. Unsafe columns were repaired using reinforced concrete jackets. Settlement observations were carried out for a sufficient period of time after repair with additionally applied test loads which showed satisfactory results