A sliced opening in structural concrete
Ten 'cones' rise from ground level to support the exhibition concourse of the museum at Wolfsburg. Each cone is a unique, irregular arrangement of canted walls punctuated with large openings.
Initially, the architect devised the cone geometry. Through discussion with engineer Adams Kara Taylor, it was agreed that the complex geometry could be defined by fixing a small number of points in space - namely the 'tangent points' where the straight walls meet the curved corners. Hence, by fixing the tangent points at two levels, a three-dimensional CAD model of each cone was created, which could be used to interpolate plans at all levels.
Once the basic geometry of the cone was defined, the architect decided the size and location of the large openings.The 'cutting plane' for each was described by setting out two points on plan and defining the angle of inclination. It was then possible to recreate this plane in the structural CAD model.
The details show the formwork drawings created for the large opening in Cone 2.
First the cutting plane was defined, and then 'true'elevations - normal to the cutting plane - were produced.On these elevations, the curves created by the intersection of the cutting plane and the corners were set out.
As well as drawings relating to the concrete formwork, drawings were needed for the fixing of the steel reinforcement.These need to show all cone walls simultaneously in true view. Consequently, the architect had to create unfolded elevations of each cone that were turned into a reinforcement drawing - a highly labour-intensive process. AKT is optimistic that in the future this process will be replaced by the direct transfer of three-dimensional CAD information to site.