The Randselva Bridge, which spans a river of the same name, is located in the town of Hønefoss, about 60km northwest form Norway’s capital, Olso, and carries the E16 motorway to Sweden.
The bridge is a continuous concrete superstructure with seven spans and 634m long, gently curving across a deep valley over the river, railway and some existing roads and forests. The box-girder deck reaches 55m at its highest point and stands on four different types of foundations. The deck is being built with moveable scaffolding system for the 60m long side spans and with the balanced cantilever method for the bridge’s 194m long main span.
There were some very significant local geological conditions to solve but the main challenge was to use solely 3D model-based drawings, a request from the Norwegian Public Roads Administration. Rising to the challenge, Armando Rito Engenharia, together with Sweco’s team, delivered a BIM model with over 200,000 sections of rebars contained within concrete that is added in 200 separate pour phases, with more than 200 post-tensioning cable anchors. With this drawing-less project workflow, there was a better understanding of the scope of work when both planning and building and an enhanced flexibility to design changes by using parametric design. Using a BIM model also allowed for a better anticipation and control of clashes which traditionally would be solved during construction, as well as excellent and eased cross-border cooperation with 95% of the information between all partners being transferred by IFC files.
This is currently the world’s largest bridge designed and built without drawings, for which it was awarded the Best BIM Project Award in 2020. Experience from Randselva bridge shows that the high level of detailing used in the BIM-model is allowing a more standarized fabrication of reinforcement and is reducing signicantly the number of questions and change requests from the site. This advanced model-based project is assumed to be very valuable for the operational period of the bridge and in maintenance purposes.
