Refurbishment of A4 motorway Küssnacht – Brunnen, section 2 Arth-Goldau

The 4.8km long national road section 2 between Arth and Goldau to be refurbished comprised five bridges and two tunnels. Within three years, the project was realised in three construction phases, divided into several phases:

• The three bridges Boli, Mettlen and Linden (335m, 140m and 540m) were comprehensively refurbished. The renovation included:
  • Separation and new construction of approx. 4,000 m bracket heads in in-situ concrete
  • partial replacement of the expansion joints
  • Exchange of the bridge bearings
  • Repair of the longitudinal beams and hammer heads
    
    In addition, CFRP lamellas and shear reinforcements were installed in the first bridge bay each. The bridge covers were replaced over the entire surface by ultra-high performance fibre-reinforced concrete (UHFB). As a result,   weather-dependent work steps such as epoxy sealing and PBD sealing sheets were no longer necessary and the construction time was significantly reduced.

• The two smaller bridges Harmettlen and Rigiaa (115m and 60m) were renovated according to the static requirements:
  • Repair of reinforced concrete
  • Mount new bracket heads and
  • Paving a noise-reducing surface course on the carriageways

• The Engiberg and Schönegg tunnels (200m and 290m) had to be refurbished over their entire surface due to damage in the portal areas. The two control centres were extended.

• The two overpasses Rigibahn and Gotthardstrasse were repaired. Where necessary, the column heads of bridge piers were reinforced.

• In the individual sections of the route, the cable blocks were supplemented and the drainage system refurbished. Finally, the binder and surface courses and the restraint systems were renewed in the entire roadway section.