The brainchild of J. Mayer H. Architects
Building owner: Stadtmarketing Karlsruhe GmbH, 76133 Karlsruhe
Design and planning: J. Mayer H. and Partner, Architekten, Berlin
Execution: Rubner Holzbau, Augsburg
Construction: March-April 2015
In the run-up to the 300th-anniversary celebration of the city of Karlsruhe, Berlin-based architectural office J. Mayer H. and Partner, architects, was awarded the contract for the design and construction of a temporary Jubilee Pavilion in the palace garden (Schlossgarten).
Complex beam structure made out of timber and steel
A flying, sculpture-like building is currently the centre of attention during the summer festival being celebrated on the occasion of the 300th anniversary of the city of Karlsruhe. The “Pavilion KA300”, its plan based on a design draft of the architectural office J. Mayer H. and Partners has been built by the company Rubner Holzbau as a general contractor and includes several additional trades, such as handrails, staircases and parts of interior fittings. The material used for this structure comprises some 338 m³ of laminated timber and approximately 30 tonnes of steel components. In order to secure short construction periods and on-schedule completion of the structure in the palace garden (Schlossgarten), considered a site of historic interest, all timber elements were prepared at the company’s site. These preparatory works comprised trimming, the provision of necessary boreholes and the application of a light greyish glaze. The elements were then delivered to the construction site ready for assembly. In the month of April, after a period of five months, all timber construction work had been concluded. Once the jubilee festivities (taking place from June 17 until September 27) are over, Rubner will remove the temporary construction and recycle the material.
The event pavilion covers a surface of 52 x 27m, reaches a height of up to 16.4m and offers a useable floor area of some 1000m². The pavilion is able to house some 300 to 600 visitors in its ground floor, which also offers enough space for a stage, a cafeteria and an information centre. The ceiling height of 5.20m underlines the spacious openness of the structure, which, in addition to the ground floor, offers an exhibition level and two viewing platforms. The structure’s volume, which is partly weather-protected by movable membranes, amounts to 2,800 m³. All in all, the structure’s shell of the cantilevered beam construction covers 12,700 m³.
The load-bearing structure is made up of 98 differently inclined, and up to 19m long columns and of a grid structure with 72 horizontal spruce glulam girders. Columns and girders are connected by means of bolts. The load bearing system of this beam structure, stiffened by slab walls and tension bars, is very complex and presents manifold connection details. In the detailed design, the connecting points presented individual parameters based on their geometry and internal forces so that each single joint had to be determined individually. The scope of works included structural design, execution design and workshop planning as well as production, delivery and assembly.
The beam structure is based on 10 longitudinal and transversal axes. Whereas the longitudinal girders and supports are arranged side by side, the transversal and longitudinal girders cross each other (joint in the transversal girder). Laterally cantilevered beams are connected rigidly.
Based on the architectural model, Rubner designed and calculated the structure with the assistance of the structural analysis software RSTAB as a three-dimensional model. A total of 2,800 beams and 2,000 nodes were required for the modelling. Due to the different geometric parameters and internal forces, each single connecting point had to be solved individually. The connections can be roughly classified as a) connections, which are characteristic for the structure, and b) supporting substructures and their connections.
- a) Foundation joints, connections of inclined columns to longitudinal girders (with and without longitudinal diagonal), connections of longitudinal girders to transversal girders (flexible and rigid connections)
- b) Substructure trussed beam (above the event area), substructure hanging truss frame (replacement of two supports in the area of the Cafeteria, which do not reach the floor), substructure strut frame (above the stage), bracings at its ends, CLT bracing box (absorption of horizontal forces from structure and wind)