1. Austria
Millennium Tower
Baierl & Demmelhuber
Innenausbau GmbH

2. Project Details Building Type Commercial Complex Project Dates–
Saint-Gobain
Products & Systems
Rigidur H (mouldings)
Rifino Top
Special structure made of
RIGIPS plasterboard mouldings
and corrugated metal

3. Contractor Company Name Main Representative Company Size
Baierl & Demmelhuber
Innenausbau GmbH
Main Representative
Mr. Johannes Demmelhuber
Company Size
540
Specialised in
from planning to installation – the
entire project comes from one
hand

4. Nimos Immobilienprojekt GmbH
Building Owner
Architect
Contractor
Innovation
Partners
Saint-Gobain Project
Manager
Nimos Immobilienprojekt GmbH
Ippolito Fleitz Group, Identity Architects
Prof. Kaufmann & Partner ZT-GmbH
Baierl & Demmelhuber Innenausbau GmbH
Jürgen Pfaffenberger (Sales rep), Thomas Huber (technical department)

5. “The shell” as a clear separation.
The impressive shell structure consists of two interlocking halves measuring 13 metres in height and 32 metres in diameter. Precision engineering as well as craftsmanship and matching products enabled the implementation of the self-supporting and free-standing shell during ongoing operations and satisfy the strict demands regarding to the quality of the surface finish.

7. Main characteristics of this project?
The installer was involved in the planning process from the start and was able to persuade the building owner to use gypsum fibreboards instead of the intended cement fibreboards. This resulted in a significant reduction of weight and enabled a lighter and leaner design. Gypsum fibreboards also made it possible to meet fire protection requirements without installing a sprinkler system.

8. Explain how it was made…
All of the radii and the convex and concave curves of the two shell halves were planned in great detail by the executing contractor – with regard to both the elaborate substructure and the cladding in the form of plasterboard mouldings.

9. Explain how it was made…
Pipe clamps and sylomer bearings attach the support structure to the building, with additional sylomer bearings securing it to the floor to absorb the movement of the more than 200 m tall tower and to prevent crack formation in the shells. These shock absorbers cushion the vibrations.

10. Explain how it was made…
The free-standing and self-supporting shell structure, its connection to the tower and also the connection between the dry lining structure and the supporting steel skeleton demanded significantly more competence with regard to planning and defining the right solution.

11. Explain how it was made…
Use of plasterboard mouldings prevents crack formation. Multiple coats ensure a surface free from sidelight despite extreme lighting conditions. Surfaces are plastered in numerous work steps. The fitters had to use ropes and harnesses to gain access to certain areas of the shell structure.

13. Explain how it was made…
Custom-made plasterboard mouldings with integrated corrugated metal elements create a walkable surface on the shell structure for cleaning and maintenance.

14. Explain how it was made…
More than 3,500 laser-cut flat steel elements were put together like a puzzle to create the steel structure. When fitting the substructure for the simultaneously and in-dependently manufactured plaster/fibreboard mouldings a dimensional tolerance of 2 mm over the entire height must not be exceeded.

15. Key challenges Demands on construction site logistics
Demand on very high competence with regard to planning and defining the right solution
Creating a perfect surface
Finding technical solutions for diverse demands
Demands on stability
Demands on fixing the shell’s structure to the existing tower
Demands on prevention of cracks
Demands on precision
A short construction period, the necessity to work during normal operations and a storage area inside the shell of just 40 square metres coupled with the corresponding demands on construction site logistics were the least of the challenges.
The free-standing and self-supporting shell structure, its connection to the tower and also the connection between the dry lining structure and the supporting steel skeleton demanded significantly more competence with regard to planning and defining the right solution.
In fact, the surface was one of the greatest challenges due to the variety of different artificial light sources and incident light from the glazed roof. The convex and concave curves with different radii and not a single straight surface represented additional difficulties.
Technical solution
for high demands on stability: The top part of the outer shell had to be walkable to enable cleaning and maintenance work to be carried out
Pipe clamps and sylomer bearings attach the support structure to the building, with additional sylomer bearings securing it to the floor to absorb the movement of the more than 200 m tall tower and to prevent crack formation in the shells.
The laser-cut flat steel elements were put together like a puzzle to create the steel structure. When fitting the substructure for the simultaneously and independently manufactured plaster/fibreboard mouldings a dimensional tolerance of 2 mm over the entire height must not be exceeded.

16. Main Saint-Gobain products and systems used
Site productivity / Rigidur H mouldings - mouldings were installed based on a strict schedule
The Shell
Individual Solutions are not provided on
Excellent surface finish / Rifino Top - Surfaces are plastered in numerous work steps
Fire Protection + Cost Saving / Rigidur H- compliance with fire protection regulations and saved the cost of installing a sprinkler system
Stability / mouldings with integrated corrugated metal elements - create a walkable surface on the shell structure
Key achievements?

17. Key achievements Involvement in the entire process
Explain why you succeeded in this project
Involvement in the entire process
Weight, Space and Cost savings
Invention of various new and individual solutions
Perfect surface
The installer was involved in the planning process from the start and was able to persuade the building owner to use gypsum fibreboards instead of the intended cement fibreboards.
The use of Rigidur H fibreboards resulted in a significant reduction of weight and enabled a lighter and leaner design. Rigidur H also made it possible to meet fire protection requirements without installing a sprinkler system.
Solutions:
the uppermost area of the shell had to be walkable to enable cleaning and maintenance work. Corrugated metal was incorporated in the plasterboard mouldings to achieve greater static strength.
Preventing crack formation in the surface was a particular focal point of the design and, accordingly, a challenge during execution. It was guaranteed by using mouldings to clad the substructure. Thus, the approximately 800 m2 large structure makes do with just a single expansion joint.
One of the greatest achievements was ensuring the surface remained free from sidelight despite different natural and artificial lighting conditions. It was achieved through numerous work processes involving lifting platforms and climbing equipment.

18. Millennium Tower Austria
Baierl & Demelhuber Innenausbau GmbH – Ippolito Fleitz Group, Identity Architects
Prof. Kaufmann & Partner ZT-GmbH
Lisa de Pasqualin
Photography Credits: Name Surname