The Belchen Tunnel system forms part of the N02 motorway, one of Switzerland’s most strategically important north–south transport corridors. The original eastbound and westbound tubes opened to traffic in 1970 and each extend approximately 3.2 kilometres. After more than five decades of continuous heavy traffic, the structural condition and age of the tunnels prompted the Federal Roads Office (FEDRO / ASTRA) to initiate a multi-stage rehabilitation programme to secure the long-term integrity of the asset.
To minimise traffic disruption during refurbishment, a third tube — the Belchen Renovation Tunnel (STB) — was constructed between 2014 and 2022. This additional bore now operates as a diversion route, allowing the original tubes to be closed sequentially for full rehabilitation while maintaining motorway capacity.
The Second Rehabilitation programme (Zweite Instandsetzung, BZI) runs from 2024 to 2035 and represents a comprehensive modernisation of the original tunnel infrastructure. The works include the sequential closure and full refurbishment of the Basel-bound and Lucerne-bound tubes, construction of seven new cross-passages and upgrades to existing connections, structural concrete repairs, renewal of waterproofing systems, drainage improvements, and upgrades to firefighting water infrastructure. Ventilation systems are being modernised and operations and safety systems (BSA) are undergoing full renewal. The programme also incorporates BIM model expansion and compliance with updated SIA standards, including SIA 197, 431 and VVEA.
Current works under Lot 101 (2024–2026) focus on the centre tube, where excavation and rehabilitation activities have been underway since September 2024.
The client for the scheme is FEDRO / ASTRA. The main contractor consortium ARGE Belchen, including Marti Tunnel AG, is delivering the principal civil works. Design services are provided by ILF Consulting Engineers, Emch+Berger Group and Lombardi Engineering. Renesco AG is responsible for specialist waterproofing, injection and grouting works.
Renesco’s scope includes the supply and installation of the tunnel waterproofing system, injection and grouting operations across the new cross-passages and selected tunnel sections, and specialist waterproofing works for all seven newly constructed cross-passages. These activities are being delivered within the 2024–2026 construction phase and are critical to ensuring the long-term durability and watertight performance of the rehabilitated structures.
Procurement activity under the programme is structured around the overarching framework MP-120093 – N02 Tunnel Belchen Second Rehabilitation (BZI), published on 09 October 2024. This service tender covers project author and design services from Phase 32 onwards and includes earthquake safety upgrades at the portal centres, immediate repair measures for the BAS tube, cross-passage works, BIM model expansion, portal cross-passage construction (BTB North and South), bypass drainage systems, firefighting water infrastructure, and compliance with updated SIA standards.
Earlier contract awards linked to the wider Belchen programme include the N02, 080008, EP STB Renovation Tunnel Belchen STB contract, awarded on 12 April 2022 to IUB Engineering AG with a value of CHF 678,073. This package covered project planning and construction management services (BSA), including additional services for Phases 52 and 53. During the earlier renovation tunnel construction phase between 2018 and 2020, Arnold AG delivered extensive basic infrastructure works across the tunnel system, including 265 kilometres of piping, 25 kilometres of cabling, 600 lighting units and the installation of operations and safety systems.
Recent tender activity confirms that ASTRA is releasing work packages progressively rather than as a single consolidated procurement. Under the MP-120093 framework, a tender for surveying services (Lot 5.1) was published under TED reference 85/2024. A further tender for safety signalling equipment (Los MIT_456 – Signale Sicherheit) was issued on 15 May 2025, covering emergency signage, illuminated exit signs and photoluminescent guidance panels. In addition, photovoltaic system installations for the Schaubrain and Central South areas were published on 21 August 2025. This phased release of packages reflects the typical procurement model for long-duration Swiss motorway tunnel rehabilitation schemes.
With the Second Rehabilitation programme running until 2035, further tenders are expected across civil, MEP and specialist disciplines. Remaining scope includes the rehabilitation of two full 3.2 kilometre tubes, construction and outfitting of a total of twelve cross-passages (existing and new), portal-area upgrades, drainage and firefighting water systems, ventilation modernisation, and the complete renewal of operations and safety equipment. As structural works progress, procurement is likely to focus increasingly on MEP and BSA packages such as ventilation, lighting, fire detection, SCADA and cabling systems, alongside safety equipment, portal works and specialist services including monitoring, surveying, BIM coordination and geotechnical support.
The Belchen Tunnel Second Rehabilitation stands as one of Switzerland’s most complex motorway upgrade programmes. It safeguards the long-term structural integrity of a critical 50-year-old transport asset, enhances operational safety through modern cross-passages and upgraded systems, reduces traffic disruption through staged execution enabled by the renovation tunnel, and ensures full compliance with current national and European tunnel standards. The project exemplifies Switzerland’s structured and phased approach to maintaining resilient, high-capacity transport infrastructure while delivering engineering excellence over the long term. For further information visit the tunnelbuilder archive click ch/65 and click here. 09/26.
