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Road viaducts – Special Works of Art

Here are some examples of road viaducts that for one reason or another can be considered special cases.

Viaduct over the Railway in the connection to the Grândola Norte Junction on the South Highway

It is a viaduct with a ribbed slab deck with a width of 15.2 m, 1.1 m in height, spans of 25 m and a total length of 165 m. The pillars are constituted by cylindrical shafts founded on piles.

This work has the particularity of the fact that the deck is fully supported on neoprene devices, thus constituting a structure with seismic isolation, according to the definition of EC8. The study of its behavior under seismic action was carried out by integrating ten accelerograms in time, obtained from the RSA power spectra, acting on a non-linear analysis model.

Client:  Brisa, Auto Estradas de Portugal, SA.

Project: 1996; Entry into service: 1998


Viaduct at km 60 189 of Linha do Norte and Viaduct to access Apeadeiro de Santana-Cartaxo.

It is a set of three works with different structural solutions, with a total length of 776 m, over the Santana-Cartaxo Apeadeiro and the Azambuja Vala. The works are inserted in a geotechnical environment of the internal border of the Ribatejo lezíria characterized by the alluvial filling of the Tagus basin, with indirect foundations, at depths greater than 50 m near the Vala da Azambuja.

Viaduct V1 has a length of 448 m, consisting of a beamed slab deck with a width of 12 m, a height of 2.5 m and spans of 42 m. The pillars are of hollow rectangular section, with a support beam, founded on piles.

The V2 viaduct is 190 m long, has a 1.10 m high ribbed slab deck, 35 m spans and 1.2 m diameter pillars/pile.


Viaduct R1 allows access to Apeadeiro de Santana-Cartaxo from Viaduct V1, inserting itself in a curved route with a radius of 40 m. The deck consists of a wide rib with a height of 1.1 m, spans of 30 m and a total length of 138 m. The current width is 9 m, widening up to 24 m at the junction with Viaduct V1. The pillars are founded on piles.

Client: REFER.

Project of viaducts V1 and V2: 2001; R1 Viaduct Project: 2004;

Contract in tender phase.


Bypass to EN211 – Viaduct of Branch A of Node 2

The projected viaduct is developed halfway up the slope in an area of difficult access, next to the meeting of the left bank of the Bridge over the River Tâmega, close to Marco de Canavezes, inserting itself in a layout in plan composed of a succession of curves of small radius. and variable radius curves.

It consists of a slab deck with a wide rib extended in cantilevers, with a width of 12 m, a height of 1.2 m, spans of 30 m and a total length of 168 m. The quadrangular section pillars will be directly founded.

In view of the slope of the slope, it is foreseen the need to use nailing and grouting during excavation for the execution of foundations.

Client:  IEP – Portuguese Roads Institute

Project: 2002

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