New Roofs Above Gates of Exhibition Grounds in Frankfurt, Germany

The steel structure of the roof above the northern gate of Frankfurt Exhibition Grounds has an oval shape with a size of 138 ft x 59 ft.

The roof is supported by pyramid-shaped columns, which appear particularly slim, and the roof gives the illusion of floating.

The winning designer was the German architect Ingo Schrader from Berlin, who worked closely with the German structural engineers Bollinger + Grohmann. The draft included circular roofs with a diameter of about 82 ft, supported by pyramid-shaped columns. In August 2013, the roof construction was finished on the northern gate.

Roof Structure for Northern Gate

In the course of further planning, the circular shape was redesigned as an oval in order to adapt to the local conditions. Its size is 138 ft x 59 ft with a maximum lamella depth of 23 5⁄8 inches. The roof cantilevers up to 33 ft and is only 62 13⁄64 inches thick on its edge.

The four columns are placed in an irregular grid. Their pyramidal shapes visually represent the downward force distribution in the columns. Due to their triangular shape, they appear particularly slim and the roof gives the illusion of floating.

The roof supporting structure was generated and optimized by means of a computational model. One may have the impression that the axes of the load-bearing lamellas are randomly arranged. However, their arrangement is the result of a computer-based design process where structural, formal, and manufacturing boundary conditions were brought in line.

Then, the lamellas were optimized in height and width. In this optimization process, RSTAB was connected with the Rhinoceros design program using an individually created VBA script. A special algorithm iteratively reduced the cross‑section dimension of the flat steel lamellas on the basis of the occurring equivalent stresses.

Programs Used for Structural Analysis

Structural Engineering Digital Planning and Structural Analysis
Bollinger + Grohmann Ingenieure, Frankfurt, Germany
Design Ingo Schrader, Berlin, Germany
Construction Prebeck GmbH, Bogen, Germany
Investor Messe Frankfurt, Germany

Project Specifications

Model Data

Number of Nodes 298
Number of Members 567
Number of Load Cases 10
Number of Load Combinations 14
Number of Result Combinations 6
Total Weight 67.049 tons
Dimensions (Metric) 39.335 x 23.128 x 5.174 m
Dimensions (Imperial) 129.05 x 75.88 x 16.98 feet
Program Version 8.02.00

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