NTN contributes to PIARC´s international workshop on underwater tunnels
27th January, PIARC hosted the workshop together with the Spanish national tunnel committee to support the ongoing planning of new infrastructure tunnel projects in Bilbao.
From Norwegian Tunnelling Network (NTN), Knut Garshol (KGRE) and Chief Scientist Eivind Grov (SINTEF) presented the topics "Methods and technologies for clarifying and handling difficult ground conditions" and "Best contractual risk allocation for underwater tunnels". In our opinion, relevant topics for the issues faced in this project.
My task is as always, identify new opportunities for the Norwegian industry and follow up the international market and in this case the opportunities in Bilbao and Spain.
Photo: Arild Petter Sovik, Norwegian Tunnelling Network
Description of the current situation in Bilbao
The current configuration of the road network in the metropolitan area of Bilbao suffers from a notable lack of transversal connections between both banks of the Nervión estuary downstream from the urban center of Bilbao. The Rontegi Bridge is the only axis of road communication between banks in this section, from the Euskalduna Bridge to the Bizkaia Bridge, separated from each of them by a distance of about 5 km.
This lack of transversal connections between the banks of the river means that the Rontegi bridge, which connects the main backbone axes of both the Left Bank (Solución Sur A-8) and the Right Bank (Corredor del Txorierri N-637 and Carretera de La Avanzada BI-637), concentrates very high volumes of traffic, with IMD values of over 130,000 vehicles, the highest in the entire foral network. These very high traffic intensities generate recurrent situations of congestion both on the bridge itself and on the roads that feed it.
In addition to the traffic problem, this configuration of the network generates a high degree of vulnerability, making the Rontegi bridge a point of maximum criticality, where any incident that temporarily affects its current capacity can have an extremely important effect on the entire metropolitan road network.
For the connection between the BI-637 on the Right Bank with the A-8, VSM/E70 and BI-628 on the Left Bank, the construction of two tunnels (one tunnel per direction) is proposed, each with two 3.50 m wide lanes, a 2.5 m right shoulder and a 1.0 m left shoulder, as well as 0.75 m sidewalks on both sides.
A very well arranged workshop on highly relevant topics, especially since cities all over the world are seeking new effective infrastructure, often complex underground tunnels and sometimes underwater, facing difficult ground conditions and complex traffic issues that limits the alternatives.