The new deck and slab
The new deck and slab
These works are part of the overall plan for the upgrading of the Sassari Olbia Route Lot 7, located at 66+360 km.
The new deck is a continuous composite steel-concrete system truss with a 3-span twin-beam layout of spans 42.10 + 42.70 + 42.10 m and a rectilinear layout.
The concrete slab accommodates the road platform for a width varying from a minimum of 13.01 m to a maximum of 16.76 m for the north carriageway, and from a minimum of 12.33 m to a maximum of 16.08 m for the south carriageway; it is frame worked on the main beams, placed at a variable distance between centre distances of a minimum of 8.40 m to a maximum of 11.60 m, and on the intermediate pin beam. The slab is cast on self-supporting concrete predalles with a thickness of 6 cm, until a total thickness of 30 cm is reached after additional casting.
Deck structure and assembly
Deck structure and assembly
The beams have a constant height of 2.20 m and are connected by cross beams with a double-T section placed at a maximum centre distance of 6.5 m, as well as by an upper bracing in the form of a St Andrew’s cross.
The diaphragms on the abutments work together with the slab by means of dowelling; this works together to stiffen the slab at the structural break with the gravel guard, greatly limiting differential vertical deformations between the guard and the slab due to the transit of vehicles over the junction.
Assembly of the deck is carried out by lifting the individual beams from below with the aid of a crane truck, after assembly of the segments on the ground, and a distortion of 5 cm.
