Brisa – Auto-estradas de Portugal
The underpasses over Vala do Carregado are located in the motorway interchange between A10 and A1, providing the continuity of the collector roads adjacent to A1 in both traffic ways. In these engineering structures, the adopted structural solution consists of a portal frame of 5 spans, comprising a main span of 25,3m in order to overpass the Vala do Carregado, two middle spans of 16,2m arising from the geometry of the piers and two side spans of 15,25m ensuring the crossing of EN1-3 main road. The reported lengths endow the underpasses with structurally balanced relations between spans.
The reinforced concrete superstructure, longitudinally prestressed, consists in a top slab 0,75m thick. Nevertheless, the major feature of this engineering structure lies in the geometry of the piers, since its “V” shape leads to a reduction in the number of supports to the ground. Thus, the hydraulic and the road restrictions were overcome, while the main span of the deck is limited to a shorter length, yielding great benefits as the deck thickness/slenderness is restricted by the vertical clearance.