La Rocha bridge in Santiago de Compostela. Extension from two to four carriageways of the existing bridge at the 67 km of the CN-550 road from la Coruña to Santiago and Tuy

Abstract

The need to continue the widening of the roadway of the CN-550 on the New Access to Santiago de Compostela up to the town limits of Milladoiro implied an important action on the existing masonry works. In these conditions, the La Rocha Bridge, with a bidirectional 7 m roadway of a total 10 m width, had to be extended to obtain the new cross section of the four carriageways, median strip and pavements. The bridge was widened adding a 6 m-wide deck to the existing platform on either side. The deck was made of prestressed precast beams and compression slabs. Prestressed concrete pier heads and metal struts were arranged as decks supporting elements which transfer forces originated by new loadings on the piers. The adopted solution made it possible to maintain the vehicle and pedestrian traffic but for four days, during which the pier heads were placed. The resistance scheme of the old bridge arcade was not altered. The new bridge was integrated into the pre-existing surroundings, preserving the local architectural heritage.