The OHIM building has 16,000m2 below ground level specifically destined towards car parking, and 15,500m2 above ground level destined towards office space and auxiliary buildings.

The underground structure consists of a reinforced waffle slab 0.35m in depth, placed on a grid of columns 7.50m x 7.20m.

The structure above ground level is trapezoidal in shape, with floor dimensions 155.00m x 16.00 m, on plan. These floors rest on headwalls (which resist the forces produced by earthquakes and imposed deformations) on the vertical circulation cores and on a grid of columns 15.00 x 7.20m2. The floor slab is a 0.45m deep waffle slab whose reinforcement is directed towards the columns, placed at every 7.20m and pre-stressed with unbonded single strand bundles directed towards the 15m span.

The building was designed and built without expansion joints, despite its large dimensions.

The auxiliary buildings which are 12.00m x 12.00m and have no inner columns, have been built with post-tensioned reinforced beams, employing high strength tendons, as well as a reinforced concrete slab 0.25m in depth.