Failure analysis of an apartment building surmounted by a RC water tank - Case study

•The structure is an apartment building in Algiers surmounted by a RC water tank.•Boumerdes earthquake of May 21st, 2003 was severely damaging to this structure.•A seismic analysis after finite element modelling is made.•The reasons for the failure of this structure are explored and the repair measures carried out.•The technique of jacketing, used as repair solution, is presented.

The structure that is the subject of interest in this work is an apartment building in Algiers surmounted by a reinforced concrete (RC) water tank with a container capacity of 1000 m3. Since its entry into service in 1962, this structure was subjected to several earthquakes (El Asnam 1980, Constantine 1985, Oued Djer 1988) without being disturbed. However, the Boumerdes earthquake of May 21st, 2003 was severely damaging to this structure. It was downgraded after a study conducted by the Construction Control Agency because the central core had undergone serious damage. As for the walls, columns, and beams, they were not affected. Through this paper, the reasons for the failure of this RC structure (building-reservoir) will be explored and the repair measures carried out. Investigation work on site, supplemented by seismic analysis after finite element modelling, will be described. The technique of jacketing, used as repair solution to improve the strength of the studied structure, is presented at the end of this paper.