New Access to Bilbao City. Spain

A complete transformation of the access to the city of Bilbao included changing the current bypass to be under ground and creating new connecting roads which included bridges and underground structures.

The project included the lowering of the bypass in a length of 320 meters, and four new cut-and-cover tunnels 67, 173, 98 and 150 m long. Work was done in close proximity to existing buildings. 

Wall types are mainly secant piles and micro piles. Several levels of tie-backs are necessary.

SILGA undertook the detail design of the structures and assistance during construction.