TABLATE II VIADUCT (GRANADA)

TABLATE II VIADUCT (GRANADA)
  • Location: A-44 Highway Granada- Motril (Granada) SEE MAP
  • Scope of Works: Detailed design
  • Structural type: Deck arch bridge
  • Construction process: Cantilever construction using temporary diagonal bracing
  • Overall length: 176,0 m
  • Spans: 124,5 m
  • Deck width: 13,5 m
  • Deck maximum height: 100,0 m

   

The Tablate II Viaduct is located on the motorway A-44 Granada – Motril, when it crosses over a deep ravine, near the village of Tablate.

The viaduct is a steel arch structure with the deck on top. It is made of two arch ribs, separated by a distance of 11,50 m. The main span of the arch, with a clear span of 125 m, is completed with both access spans, 25 m long, so the overall length of the viaduct is 175,0 m. The deck is a composite girder, 13,5 m wide. It has two lanes, 3,5 m wide, and wide hard shoulders, designed for a future highway widening to 3 lanes.

The two steel arch ribs are connected by transverse beams. The arch ribs sections are rectangular with dimensions of 1,20×1,80 m. The arch axis is parabolic, and the rise is 21,25 m. On the arch, there are 12 steel spandrel columns. A triangulated steel frame is installed on the arch abutments, in order to stiffen the structure, against strong seismic and transverse wind loads.

The deck is a composite concrete-steel structure 176,0 m long. The steel structure is made of two longitudinal chords, over the arc ribs, and transverse beams every 4,15 m. On these transverse beams precast panels were installed. Finally, the cast on-site deck slab, 0,25 m thick, was made.

A cantilever construction was used for the steel structure, using the deck as the upper strut chord and the arch as the bottom tie chord. Therefore, the spandrel columns are subjected to large flexure loads. To reduce these loads a temporary diagonal bracing bar system was installed. The tension reaction transmitted by the deck is absorbed at the deck anchors installed at the abutments. When both cantilevers were built, the final crown segment was put into place, removing the temporary diagonal bars and the deck anchors.