Oodi – Helsinki Central Library: Making the architectural vision a reality

Abstract

ABSTRACTThe Helsinki Central Library is a landmark project, delivered as part of the “Finland 100” programme to celebrate 100 years of the independence of Finland. ALA architects delivered the winning entry to the architectural competition held in 2013. In 2014 Ramboll Finland won the structural design contract for the project, taking the project from conceptual architectural design through to completion of construction in 2018.The main structural system is fundamentally a steel frame solution designed to Eurocode. Two EXC4 classified, 109m span, tilted arches carry the two main floors and roof of the building. Post‐tensioned cables tie the bases of the arches to provide a tied‐arch structure. Other post‐tensioned cables in the floor system and concrete cores hold the tilting arches in position. Transverse trusses allow the cantilevering balcony to be delivered. 2400t of steel have been used to deliver the main frame structural solution.With careful and considered design, fabrication and construction, high quality to good tolerances and stringent requirements have been successfully achieved.An overview of the bridge‐like structural system that has been conceived and developed for the project shall be presented. Some of the challenges encountered and resolved in the design shall be discussed, as well as an overview of key decisions made to handle project delivery budget and timetable requirements.