TÍTULO

National Museum Of Qatar - Connections between Disks with Different Geometries

The National Museum of Qatar is the flagship in a series of national cultural and educational projects. Inspired by desert rose, the museum is a four story, 300 meters by 200 meters sculpture of intersecting disc shapes up to 80 meters in diameter. The structural solution settled on radially and orthogonally-framed steel trusses, supporting fibre-reinforced concrete cladding panels to create the required aesthetic and performance of the building envelope. Structural Modeling The key challenges for the design resulted from the highly complex geometry of the disc interaction.

The spaces in the building are created by the interstices between the discs; any alteration to the architecture involves moving discs and thereby moving the structure within the discs. The structural team developed a parametric Generative Components script-based tool to automatically create wire-frame geometry in the correct position within the architectural Rhino envelope. The basic wire-frames were further populated with property and loading data using spreadsheet-based automation. Custom-designed spreadsheet macros were further used to combine separate disc models into larger combined models for structural analysis.

Element strength checking was automated as far as possible, to make practicable the design of the 250,000 steel elements. The analysis models were used as the basis of the production Tekla model, directly translating geometry, section data and also key annotation such as disc-to-disc interface nodes. The Tekla model was issued to the contractor at tender stage for accurate pricing. The model has been kept up to date and reissued as the design has been completed, and contains the live drawing files needed to communicate information in 2D.

On site, the contractor has adopted and developed this model to a fabrication level of detail, and made use of Tekla phases and classes to keep track of issue status of recent updates. Also at tender, the Tekla model was used to interrogate concrete volumes in order to produce accurate steel reinforcements. Superstructure Steelwork Connections The scheme for the building involves many intersecting steel framed discs and therefore results in numerous connections between discs with different geometries. An effective normalized solution was established through a connecting CHS where a significant number of connections are based.

It tolerates a large range of incoming member arrangements. To communicate this to the contractor, connections were designed, detailed and illustrated on drawings with 3D perspectives and 2D sections. The nature of the each connection was such that the geometry and therefore design could not properly be understood without interrogation of the intersecting members in 3D, for which Tekla was invaluable. Key Processes 1600 individually designed piles with bespoke trim and toe levels were carried out in Tekla using a macro script to read the required data from design spreadsheets.

Drawing and labeling of interface connection tags in 3D space was carried out using a combination of the GSA to Tekla plugin to create spherical objects at the required ‘node’ locations, and spreadsheet lookups were used to compare and update those object properties from the labeled connection nodes in the analysis model. Clash checking was carried out in Tekla BIMsight with the same .ifc exports as for MEP coordination. Verification of the drawn structure was made possible by visual checking of the Tekla model using the Tekla viewer, model reviewer and web viewers, and spreadsheet scripts to automatically compare geometry and sizing from Tekla and GSA text data outputs.

Effective communication with off-site/remote technicians around the world was possible using the Tekla comment tool plug-in. This captured comments and marked up screenshots, but could also be stored in a live ‘cloud’ type server account for sharing with the design team, without downloading and updating new files. Challenges Solved using Tekla Tekla BIMsight was instrumental in identifying and resolving clashes within the production model, focusing engineering input in the right places. The complex 3D structure was broken down into 2D ‘component drawings’ for each disc, in order to communicate the design clearly and succinctly to complement the client’s contract hierarchy.

The Tekla model was a key input into the team’s Digital Projects BIM model to effect cross-discipline coordination. Connection design was carried out in collaboration with fabricators, identifying and modeling ‘real’ geometry examples to communicate connection design intent in 3D. Tekla’s system of phase identification and coloring was essential in identifying and tracking change for the contractor.