World’s longest bridge built exclusively for public transport and people

Kruunuvuori Bridge (Crown Bridge) is a 1.2‑kilometre cable‑stayed bridge spanning the Kruunuvuorenselkä strait in Helsinki, linking the island of Laajasalo with the inner city. Designed exclusively for light rail, pedestrians and cyclists, the bridge reshapes everyday mobility by prioritising public transport and active travel over private cars, while strengthening connections between neighbourhoods across the city.
Ramboll were appointed as construction designer for this 1.2km long cable stayed bridge. The bridge will shorten the distance from the islands of Laajasalo to the centre of Helsinki, thereby making it easier to travel the distance by bike or even on foot. The completed Kruunuvuori Bridge will be special in many ways. It will be the only bridge in the world of this size that caters only for light rail, pedestrians, and cyclists.
People‑centred connectivity

Kruunuvuori Bridge strengthens everyday mobility in Helsinki by connecting Laajasalo with the inner city through light rail, walking and cycling. By excluding private cars entirely, the bridge prioritises people over traffic, shortens travel distances, and makes active and public transport realistic, attractive choices for daily trips across the city.

Design for longevity

Designed for a 200‑year service life, the steel‑concrete composite structure embeds durability and lifecycle thinking from the outset. Careful detailing allows wearing parts to be replaced over time, ensuring long‑term performance under repeated tram‑induced fatigue while maintaining structural integrity and value for future generations.

Reducing risk in a marine environment

Delivered in demanding open‑sea conditions, the project required a construction approach that minimised risk and increased predictability. In close collaboration with the contractor, the installation method was redesigned to use large prefabricated segments placed by marine crane on temporary supports, accelerating delivery while improving safety and weather resilience.

Digital design enabling collaboration

A parametric information modelling approach was used to code the entire bridge geometry. Design automation allowed changes to update automatically across the model, enabling design and data modelling to progress in parallel. The project’s end‑to‑end BIM methodology was recognised as Overall Winner of the 2024 Tekla Global BIM Awards, including the Infrastructure category, highlighting collaborative model‑based infrastructure delivery.

Collaboration has been decisive from the outset. We began jointly developing this project and its construction method at a very early stage. The move from cantilever erection to large‑segment installation on temporary supports is a good example of the power of partnership.
Ilkka Ojala 

Chief Designer, Ramboll 

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