The hanging gardens of Zug

22.06.2021

A new innovation quarter is being built in Zug - the Tech Cluster of Zug. In the midst of the new and renovated buildings stands «Semiramis». A tower with five oversized plant bowls made of wood. Timbatec and TS3 are pleased to be part of this lighthouse project.

«Semiramis», the hanging gardens of Zug rise more than 22 meters into the air in front of the new main building of V-Zug. They provide habitats for native plants and small animals, bringing natural diversity to the new neighborhood. «Semiramis» is a sign of the increasingly close cooperation between machines and people. For example, Gramazio Kohler Research, ETH Zurich worked with various internal and external partners to develop a fully robotic assembly process for positioning the cross-laminated timber panels with millimeter precision. Four robots working simultaneously make this process possible.

Connection with TS3 joints

The faces of the individual cross-laminated timber panels are first treated with primer. After the boards are in the correct position, the TS3 casting resin is applied. The cross-laminated timber panels can thus be joined to each other by joint grouting without applying pressure to the faces. Timbatec developed this process in several research projects with the ETH Zurich and the Bern University of Applied Sciences. Today, it is mainly used for the construction of floor slabs, but also enables structures such as «Semiramis».

RWIND Simulation by Dlubal Software 

«Semiramis» is a highly complex affair not only in assembly and production. The five plant shells are all differently shaped and up to 10 m in diameter. The slender and tall structure is lushly planted with large bushes and trees and thus has a stately dead weight. At the same time, it represents a large attack surface for the wind. 

Thanks to the advantageous round shape of the shells, it is guided around the structure. Nevertheless, the stiffening of the structure with its eight slender columns is a challenge. The wind pressures on the shell were calculated with a fluid mechanical RWIND simulation from Dlubal Software, which simulates the flow around the structure in a wind tunnel. In addition, due to the slender construction, resonance effects along and across the wind direction had to be considered in the calculations.