Tenders should be invited in the final quarter of this year for the construction of a 3.2km long road tunnel that will bypass the conurbation of Andorra la Vella/Escaldes-Engordany (And/Esc) in Andorra.
The final twin tube construction design, chosen by the Andorra government, should be completed in the summer 2003. Priced at US$70.1M, it is US$6.4M cheaper than the alternative design, which was a single tube with three lanes (with a reversible central lane).
The design calls for two 3.5m-4.5m diameter pilot tunnels to be bored with a TBM, which will then be widened by drill and blast to 8.5m. Cross passages will be constructed every 240m.
Recent geotechnical analysis has confirmed different types of metamorphic calcareous hard schists with shales. The maximum cover is about 400m.
The client is primarily inviting tenders from mainly French and Spanish contractors, but will also welcome interest from further a field.
The tunnel is being built to direct vehicles away from And/Esc, where the narrow streets cannot cope with the increase in traffic. The new route, which is an important link between France and Spain, will be mandatory for heavy goods vehicles.
Spanish consultants, Ingeotec SA, in JV with local company, Sigma, is managing the project on behalf of the Andorran government.
