Existing office and wholesale stores building complex on the National Road, Metamorfosi Attica.

The complex is made of reinforced concrete and it consists of two independent buildings, separated by expansion joints, each one with two basements, a ground floor and two floors.

The buildings feature relatively large spans of approximately 15.00m, in the interior, which are bridged with “post-tensioned” beams.

During the Athens earthquake in 1999, severe cracks occurred, as expected in buildings of this type: with large spans and proportionately few columns, with no shear walls and cores.

In such buildings the deformations are very large in the event of an earthquake.

To address the problem, buildings were strengthened by the addition of four anti-seismic reinforced concrete cores.

Two cores were added to each building externally without any intervention at the interior of the buildings.

The cores were constructed in a “U” shape to strengthen the buildings in both directions, they were fully attached to the existing load-bearing body with the latest connection technologies and they had their own new foundations constructed at the second basement’s floor-slab level, fully connected to the existing foundation slab.

What is innovative and original about the above described statics interventions is that they are realized at the exterior of the buildings, with the buildings in operation.

The strengthening construction works were completed within two months with absolute cost efficiency and human life safety and gave the buildings the earthquake-resistance characteristics of a new, contemporary building.