At the heart of the Singapore Sports Hub is the new National Stadium, a state-of-the-art 55,000 seat sports venue, air-cooled for comfort and designed with a movable roof and retractable seating to support the widest range of sports and leisure events throughout the year. It will be the first stadium in the world custom designed to host athletics, football, rugby and cricket all in one venue, converting from one mode to another within 48 hours.
With a span of over 310m, the National Stadium roof is the largest free spanning dome structure in the world. The project is an exemplar of collaborative design between the architectural vision of Arup’s sports venue designers and the structural engineering team using 3D modeling techniques. The design team used Tekla to achieve the remarkable feat of optimizing the fixed and movable roof design. The result is a highly buildable roof that is extremely efficient, lightweight and sophisticated in form.
Interoperability between the design and documentation model was a special challenge. Arup was able to optimize the roof structure using our in-house analysis software. Using a plug-in which linked our analysis to the Tekla model, Arup was able to automatically update the Tekla model to suit the latest optimized design geometry. This would not have been possible using traditional methods.
The roof structure of the National Stadium is comprised of a series of 3D triangular trusses fabricated from CHS ranging from 139.7mm to 508mm in diameter, producing architecturally appealing curved lines in the exposed structure. These curved lines posed many challenges to the fabricator but the use of 3D Tekla / BIM techniques enabled the team to overcome them. The base Tekla model defining the geometry and member sizes of the roof structure provided by Arup was important to ensure that all connection design information was properly imported into the base model. In order to ensure that the design team’s intentions were fully reflected in the Tekla model, Yongnam, the steel contractor, developed a system which checked all the essential data stored in the Tekla model against the design data for each and every intersecting node.
From the outset, the Arup design team recognized that the successful delivery of this roof structure needed a fully integrated approach to the architectural and structural design, and subsequently construction. Arup established a common interface to allow the parametric intelligence to be established in Digital Projects
(DP), Rhinoceros or Oasys GSA (Arup’s structural analysis package) to be transferred between the software. The DP model was then linked to the Arup's GSA model, allowing optimization of the roof’s form from varying truss depths, layout to arch rise and other parameters that define its geometry. The efficiency of this process allowed the team to iterate through numerous design solutions.
Once the structural sizing optimization was complete, the analysis model was converted into a 3D ‘Tekla Structure’ BIM model from which all the construction drawings were produced. Additional software was written to further extract design information from the analysis model (such as connection design forces and fatigue stress concentration factors) and embed them within the Tekla model. This process allowed the BIM model to be issued to Yongnam, containing all the information necessary to deliver the roof’s complex structure.