Kruunusillat (Crown Bridges)

The proposed scheme has been developed to provide fully integrated traffic connections with the terrain and landscape providing high quality environmentally sensitive solutions at all of the landing points required by scheme including those between Kalasatama and Korkeasaari, Korkeasaari and Palosaari as well as the main crossing between Palosaari and Kruunuvuorenranta. The landscape, urban planning and lighting design has been integrated seamlessly with the bridge and causeway design and the solution provides enhanced arrangements at all shores, the connection to the Zoo, tram station and the Island of Palosaari. Indeed a viewing area has been incorporated at the eastern most end of Palosaari to provide an opportunity for public amenity and to view the stunning vista including the enhanced views offered by the proposed unique multi span cable stayed structure.

At commencement of the scheme on the west shore between Kalasatama and Korkeasaari a slender and elegant varying depth multi-span steel composite viaduct is provided which accommodates pedestrians on the southern side and both pedestrians and cyclists on the northern side. At Korkeasaari provision is made for pedestrians to continue at track level or to deviate to the south via landscaped ramps to either the Zoo or below a slender underbridge to the existing bridge connection. Cyclists deviate at the north east corner to continue onwards or enter the Zoo. Desire line analysis has been carried out and the station has been provided immediately to the east of the 3 span structure to reduce journey time for users alighting and to further enhance user experience.

Between Korkeasaari and Palosaari a low lying causeway has been provided to mitigate visual impact whilst respecting flood levels. Both pedestrians and cyclists travel on the northern side to allow for any future light rail connection. The causeway is provided with transverse culverts below water level to mitigate impact on marine life.

At Palosaari and Kruunuvuorenranta pedestrians and cyclists have the choice to cross the main multi-span cable stayed bridge on the northern or southern side as the proposed solution provides a symmetrical arrangement with the tramway separated vertically from the adjacent cycle / footways. Users can either enjoy the views of Helsinki City or the view to the seaward side as they see fit.

An amenity area is provided at the eastern tip of Palosaari with viewing platform to the main bridge and out to sea. This area provides long views of the bridge but also allows a closer view of the bridge detailing. The commitment of the Designers to excellence in bridge design and attention to detail in the development of the presented solution ensures that the structural arrangement pleases the eye from close quarters as well as when viewed in its entirety.

The main multi span cable stayed bridge incorporates slender centrally located sculpted pylons with a visually slender deck and attractive supporting piers. The cable stays are provided in a fan arrangement giving the impression of “sails over the sea”. A symmetrical vertical alignment is provided with a pair of back to back curves horizontally. These are considered essential to express the bridge form and create visual interest from all viewpoints and importantly for those using the bridge a clear definition of their journey. A span module of 160m has been adopted and the vertical height of the pylons has been limited in keeping with the low lying nature of Helsinki City.

During all stages of the design process the design team has sought to deliver a striking bridge structure with well considered connections which enhance user experience and the unique setting offered by this scheme at the same time as delivering value for money both in terms of ease of constructability and whole life cost.


AUTHORS DETAILS

Company Principally Responsible:
Roughan & O’Donovan – Dr. Tony Dempsey


AUTHORS AND EXPERTS

Competition Managers:
Roughan & O’Donovan – Mr. Marc Jones
Finnmap Consulting – Mr Pertti Kaista

Bridge Designer Structural:
Michel Virlogeux Consultant - Dr. Michel Virlogeux
Roughan & O’Donovan – Dr. Tony Dempsey

Bridge Aesthetics and City Planning:
Soberco – Mr. Pierre Million

Landscape Design
Byman and Ruokonen - Mrs. Ria Ruokonen


Street and Traffic Planning:
Finnmap Infra - Mr. Rauno Matila

Geotechnical:
Finnmap Infra - Mr. Vesa Oksanen

Cost Control:
Kesälahden Maansiirto - Mr. Antti Rämä

Environmental Expert
YVA - Arto Inkala

Lighting Expert
Granlund – Mrs. Sanna Forsman