CASE STUDY

Dampening vibrations for Farris Bridge

The new Farris Bridge is designed with high-rise slanted towers, which are visually stunning but have the side effect of creating vibrations or large rotations and movements in the 24 cables attached to the towers. Vipo (previously Trelleborg Offshore Norway) was able to help resolve the issue by installing rubber vibration dampeners to the cable anchors.

The background of the project

Farris Bridge is a motorway bridge on E18 through Larvik in Vestfold, Norway. The bridge is a 570 meter long sloping cablestay bridge made of steel and concrete which crosses Lake Farris near Farriseidet as a part of the road project E18 Bommestad–Sky. Work on the bridge was initiated in 2013 and opened in March 2018. With its beautiful architecture and tall tilted towers, the Farris Bridge is set to become a visual landmark at the exit to the city of Larvik. Farris Bridge was built by the co-venture between PNC and Implenia called Joint Venture Farris Bru ANS (JVF) and the contract is for a NOK 719 million.

JVF contacted Vipo in August 2017 to discuss how our rubber expertise could help solve their vibration challenge. Following inspections of the project, Vipo’s engineering team started the process of designing a proposal to supply rubber dampeners.

In September 2017, Vipo and JVF signed a contract for the production and delivery of rubber dampeners as well as installation training and assistance. Working in close contact and cooperation with the customer and with short and effective processes underway, everyone involved actively worked to meet the project deadline.

Delivering Distinctive Dampeners

Vipo designed distinctive dampeners to suppress the vibrations in the supports for each of the 24 bridge cables in the main tension section on the Farris Bridge.

The rubber-based vibration dampers are manufactured from high-quality chloroprene giving the dampeners good mechanical properties, as well as excellent weather and aging properties.

During installation, the vibration dampers are compressed so that they fill out and form a compact rubber damper between the bridge cable and the steel pipe that forms the lower cable anchor.

Each anchor attachment is unique, so all 24 vibration dampers were customized for the project. The complete solution was delivered with an installation manual so that the customer could complete the installation of the dampeners using their own team after receiving training from a Vipo supervisor.

“We want to thank Vipo (previously Trelleborg) for the cooperation and the professional approach which the company has had for the delivery of a complete design of a custom product for the rubber dampers for the sloping cable-stays on the Farris Bridge. The product was accepted by our customer, the Norwegian Public Roads Administration, without further customizations. We were very satisfied with the quality of the drawings, the material specifications and the installation documentation that was delivered with their “hands-on approach” to training JVF’s installation staff on the job. We look forward to further collaboration should these products be required on some of our future projects.”
Roger Whiston – Project Manager, Farris Bridge.

“Our high-performance solutions are used to seal, damp and protect bridges, tunnels, and buildings, throughout the world and are designed to maximize the life of infrastructure assets while minimizing disruption. We are grateful for the opportunity to work on such a high-profile project that will be seen by everyone crossing the bridge through Larvik.”
Thor Hegg Eriksen – Managing Director, Vipo