Underground Civil Works

Completion works of the Amorebieta-Muxika section. Urdinbide tunnels

Owner: UTE Urdinbide (Vda. de Sainz-Lurpelan-Exc. Cantabricas)

Client: Interbiak

The aim of the works in the section where the Urdinbide tunnels are situated is the improvement of the current road BI-635 from Amorebieta to the road down from Autzagane, with a total length of almost 3,500 m.

The most remarkable element is the Urdinbide tunnels, comprising two tubes with two lanes each.

The main characteristics of the Urdinbide tunnels are the following:

  • Type: one-way, non-urban (class I according to Regional Decree).
  • No. of tubes: 2 (1 in each direction).
  • Longitudinal slope: descending towards Muxika.
  • Maximum cant: 5.10 %.
  • Minimum cant: 2.00 %. (in transition 0.00%)
  • Length: 695/693 metres.
  • Gage: 5 m (between outer shoulder lines).
  • Free cross-section: 82.88 m².
  • Theoretical area of excavation: 107.33 m², according to the supports installed.