Kalasatama (Fish Harbor) is a new residential and business district of Helsinki, and it is estimated to house up to 20,000 citizens by 2030. It is surrounded by a seaside promenade that will be connected to recreational park, sports and zoo areas of the neighboring island by a 170-meter pedestrian and cycle bridge. Construction work of Isoisä bridge was started in August 2014, and the bridge will be open for public use by the end of August 2016.
On the residential side, it starts as a Langer girder and divides to an arch bridge structure on the park side. The bridge has a span of 150 m. Its useful width at the park end and in the middle is 4 m and widens towards the residential area as light-traffic lane divides to reach the two sides of the arch. Here the reinforced concrete abutment is founded on bored piles and on the other end the arch branches are anchored straight to the bedrock. The bridge’s superstructure is a steel construction and the orthotropic deck is suspended from the arch with 22 pairs of tension rods. Steel assemblies are welded together on site. The project also includes construction of the pedestrian and cycle paths the bridge will connect.
An important objective has been to utilize the building information model instead of drawings in the procurement and construction of the project. The target was to include in the model all essential information needed by the contractors. Because of this, the project team has paid special attention to what and how accurately to model as early as in the beginning of the design phase. In principle, the contractor and all other project participants have been guided to use the BIM in their own work and when communicating with the rest of the team. BIM-based data transfer has been maximized and the amount of paper documents minimized during construction, too. At the same time, the objective has been to make the contractor utilize the model in such scale and variety that the team’s experiences and dialog would yield the best data transfer practices. The architect’s geometry model created by the functioned as the source data for structural design. All steel and concrete structures were modeled, including reinforcing bars and similar details. Steel structure was modeled containing the coordinate points for elevation.
