These are ten reinforced concrete apartment buildings, built in 1969, in Nea Erythrea, Attica.

Each one consists of two underground levels, “pilotis-style” ground floor and eight more floors.

The apartment buildings are perfectly symmetrical and have a core of reinforced concrete, of inadequate cross-section.

During the Athens earthquake in 1999, some the buildings’ columns at the pilotis level suffered shear failure, and the cores’ shear walls were severely cracked at the same level.

Fortunately, the collapse was avoided due to the short duration of the earthquake.

It was deemed necessary to repair the damage and strengthen the load-bearing structures without evacuating the buildings, as each one was home to about 20 families.

Cubus was entrusted with the strengthening and upgrading design of the three buildings, the rest being strengthened in a different way.

Cubus’ proposal was to add two new reinforced concrete cores, externally, on both sides of each building, along the entire height, after cutting and removing the balconies.

The new cores are appropriately attached to the existing load-bearing structure, with new foundations under the second basement floor level.

It was also required to strengthen the first basement roof slab, in the area around the new cores, to bear up the increased horizontal stress in a potential future earthquake.

Apart from being restored, the walls and columns of the “pilotis” needed strengthening and to this end, reinforced concrete “jackets” were constructed all around them, fully attached to them.

The interventions were carried out externally, without disturbing the interior of the apartments and without affecting the architecture of the buildings.

They were completed in a short period of two months.

The statics interventions design was also studied – in terms of the facades’ aesthetics – by the architect Nikos Ktenas