Apartment building with ground floor, first floor and a smaller basement, built entirely out of reinforced concrete, in 1970 in Piraeus.

Our goal was to add two floors and a third, smaller one on top.

At first the evaluation study showed that a strengthening of the existing bearing structure against earthquake is required, as well as that the additional floors should be constructed applying a light weight structure, in order to avoid the strengthening of the internal columns.

The ground floor and the first floor remained occupied during the construction.

Peripheral shear walls of reinforced concrete, with rectangular and “L” form, as well as their coupling beams, were added on the façade and on the back side.

Some shear walls were founded on basement walls and others – at the façade – were based on new foundations at the existing foundation level of the building.

The new foundations were connected to each other and to the existing ones.

The reinforced concrete shear walls extend to the full height of the three storey’s of the building to ensure the best seismic behavior.

Furthermore, for the erection of the additional floors a steel profiles construction was set up and composite slabs with trapezoidal metal sheet were constructed, all for reduced weight.

The infill walls were made out of brickwork and an external thermal insulation composite system was applied over the whole external surface of the building for energy saving.

The solution applied, has proved to be of high quality, completely economic and safe against earthquake.