Warehouse with exceptional ceiling thickness

A bird's eye view of the Tojo furniture store (©Kullmann)

Since 2000, Tojo Möbel GmbH has been distributing designer furniture globally that impresses with a combination of elegance and functionality. With the construction of a warehouse, which also includes a show room and an office, the company from Schorndorf is reacting to its growth. The engineers of SCHATZ projectplan GmbH, who were responsible not only for the architecture and the technical building equipment, but also for the structural design of the building, carried out all static calculations with FRILO software.

In order to be able to optimally store and display their designer furniture, the furniture manufacturer Tojo needed a new warehouse that would meet the growing requirements for accommodation and presentation. A suitable site was quickly found for the new company headquarters in Schorndorf. The tasteful new building measures 1,210m². The largest part of the building area is taken up by the storage hall, which extends over the ground floor and, with a ceiling height of 9m, provides ample capacity for the furniture. The property, including the storage area, also has a full basement. Half of the basement is used as additional storage space, the other half as underground parking. The heart of the building, however, is the light-flooded showroom for the furniture, which has won design and innovation awards, on the third floor.

The Building Model as the linchpin

In order to be able to carry out the structural calculations, the planners Dipl.-Ing. Bernd Weissinger and Dipl.-Ing. Florian Neher first reproduced the entire construction floor by floor with the GEO Building Model from FRILO on the basis of a 3D model previously drawn in Allplan. They then used the same program to determine the vertical and horizontal load transfer floor by floor. For the foundation, this load transfer was used as the basis for the precise dimensioning of all geotechnical verifications and the determination and specification of the necessary reinforcement in the FD+ and FDS+ foundation programs. The prestressed concrete girder under the roof of the large warehouse were calculated with the B8 program. FRILO solutions were also used for the design of the concrete (B5+) and steel (STS+) columns.

Exceptionally high payload

One of the client’s concerns, however, presented the structural engineers at SCHATZ projectplan GmbH with a special task: at 50 kN/m², an unusually high live load was planned for the ceiling above the basement. “Such a high payload allows great flexibility in the use of the building, but also makes the dimensioning of the ceiling a key challenge,” says Bernd Weissinger, head of structural analysis and design at the SCHATZ Group. In order to determine the dimensioning and specification of the ceiling thickness and reinforcement as precisely and quickly as possible, the planners transferred the component from the Building Model to FRILO’s PLT Slabs by Finite Elements. “Since we are actually used to quite different loads, we had to feel our way around a bit. But the beauty of the interaction between GEO and PLT is the possibility to change the dimensions of the slab or even the concrete quality, and the GEO simply absorbs the resulting new dead weight of the slab. In this way, we were able to quickly dimension the required slab thickness via the deformations during the preliminary design. In the process, a rough final deformation could be deduced from the output of the deformation in state I by means of a factor,” Weissinger describes. And Florian Neher, deputy head of the structural analysis and design department, adds: “As a user, you can get initial results quickly and efficiently.”

"But the beauty of the interaction between GEO and PLT is the possibility to change the dimensions of the slab or even the concrete quality, and the GEO simply absorbs the resulting new dead weight of the slab."

Dipl.-Ing. Bernd Weissinger, Head of structural analysis and design at the SCHATZ Group

Ample shear reinforcement

After carrying out all the calculations, the engineering office, using the PLT, determined a necessary thickness of 35cm for the ceiling above the basement, which consequently had to be provided with ample shear reinforcement. This shear reinforcement was planned using spatially curved round steel stirrups. The required installation distances and instructions were shown accordingly in the form of implementation details in the associated reinforcement plan.

Cantilever at the frog

The two ceilings that connect to the exhibition space also posed a challenge to the engineering office. The inviting window front that surrounds the 3rd upper floor cantilevers on two of the four sides by 3.30m and 2.80m respectively. This projection, which the client wanted to have without joists, in combination with a column-free exhibition area, meant that the ceilings above the 2nd floor (38cm) and especially above the roof (45cm) also had to be exceptionally strong. Once again, the engineers used the slab programme to determine the required slab thicknesses to ensure stability and minimise deflections at the slab edge.