Relief for Noia: New Stay Cable Bridge ensures Summer Months without Traffic Jams
During the summer months, the town of Noia near Santiago de Compostela in northwestern Spain experiences exceptionally large traffic volumes. On average, two million vehicles per year drive to the estuary beaches of Noia and Muros.
Today, Noia’s residents finally have some relief: Since December 2013, a new stay cable bridge crosses the estuary near Noia. The bridge connects Testal with A Barquina and is the main part of a new road to Santiago de Compostela that significantly reduces travel time between the two cities.
The new viaduct is a prestressed concrete bridge with two precast beams supporting a concrete slab. The bridge has a total length of 1,700m and average spans of 30m. This excludes the spans carried by stay cables – two of those spans are 48m long, and the middle span has a length of 102m. The bridge deck has a total width of 16.5m and accommodates two traffic lanes as well as two pedestrian and cycle paths.
The stay cables are mounted on two symmetrical steel pylons that reach a height of 26.3m above the bridge deck. The 24 stay cables are arranged symmetrically on the main bridge with 12 tendons anchored at each pylon in a fan-shaped arrangement.
DSI Spain supplied and installed Type DG-P 31, DG-P 37, DG-P 55 and DG-P 61 Stay Cables in lengths between 21 and 55m. The stay cables meet all fib requirements and are inserted into white ducts with an external helix to reduce the wind-rain induced vibrations. The strands with a total weight of 59t are galvanized, waxed and sheathed, fulfilling the technical requirements of prEN 10337.
Installation work was carried out and supervised by DSI Spain’s experienced employees. The stressing operation was smoothly executed thanks to the patented ConTen System, and the fine tuning of stay cable forces was achieved using DSI’s gradient jacks.
As an additional reinforcement of the precast concrete segments in the main span, DSI supplied and installed 48 external Type 27-0.62" DYWIDAG Strand Tendons. The precast concrete segments, which were 30m long on average, were tightly connected using Ø 36, 40 and 47mm DYWIDAG Bar Tendons near the abutments. In total, DSI supplied 16t of DYWIDAG Bar Tendons with accessories for this purpose.