Elements - Foundation
1. The Foundation – A Stable Base
At the very bottom, the massive foundation ensures the stability of the Donauturm. It supports the entire structure and secures the tower against wind and vibrations.
(c) Rennhofer
Elements- Tower Shaft
2. The Tower Shaft – The Slim Core
The slim concrete shaft extends upwards and supports the main areas of the tower—including the observation deck, café, and restaurant.
Element- Tower Head
3. The Tower Head – Where Everything Rotates
At the top section, the tower head houses the rotating platforms of the restaurant and café. Here, visitors can enjoy the spectacular 360° view.
Element - Steel Mast
4. The Steel Mast – The Tower’s Crown
At the very top of the tower shaft, the steel mast extends into the sky, bringing the Donauturm to its final height of 252 meters. This is also where logos and technical equipment are mounted.
The Foundation – The Stable Base of the Donauturm
1 | Shallow Foundation Instead of Deep Foundation
Instead of a deep foundation, a shallow foundation was chosen, as the ground was stable enough to support the structure. This not only saved costs but also sped up construction significantly.
The Foundation – The Stable Base of the Donauturm
2 | An Extraordinary Design
The foundation is not a simple concrete block but a circular ring with an outer diameter of 31 meters and an inner diameter of 10 meters. It is buried about 8 meters underground.
(c) Bernhard Rennhofer
The Foundation – The Stable Base of the Donauturm
3 | Perfect Load Distribution
Thanks to its three different shell structures, the foundation evenly distributes the massive weight of the Donauturm, ensuring maximum stability.
(c) Bernhard Rennhofer
The Foundation – The Stable Base of the Donauturm
4 | Built in Record Time
The foundation was completed in just two months—allowing construction of the tower shaft to begin as early as October 11, 1962.
The Tower Shaft – The Heart of the Donauturm
1 | A Slim Reinforced Concrete Tube
The tower shaft is a 182-meter-high tube made of reinforced concrete, anchored into the foundation. Its diameter tapers from 12 meters at the base to just 6 meters from a height of 145 meters.
The Tower Shaft – The Heart of the Donauturm
2 | Strong Yet Lightweight
The wall thickness decreases from 50 cm at the base to just 25 cm at the top, reducing weight without compromising stability.
The Tower Shaft – The Heart of the Donauturm
3 | Two High-Speed Elevators
Inside the tower, two elevators transport visitors to the observation deck in just 35 seconds. The elevator shaft begins in an “E” shape and transitions into a “T” shape above 65 meters.
The Tower Shaft – The Heart of the Donauturm
4 | Record-Breaking Construction with Slipform Technology
Instead of using traditional scaffolding, the tower was built using slipform construction. The concrete was poured in sections, and the formwork was continuously raised, allowing the tower to grow 4 to 5 meters per day.
The Tower Shaft – The Heart of the Donauturm
5 | Harsh Conditions in Winter 1962/63
A severe winter halted construction for two months. At 150 meters high, freezing temperatures and strong winds made work difficult. Heaters and straw mat covers were used to protect the concrete from frost.
(c) Matthias Schmitt
The Tower Shaft – The Heart of the Donauturm
6 | Completion on February 28, 1963
Despite these challenges, the tower shaft was completed in just a few months. By February 28, 1963, the foundation of the Donauturm was finished—allowing the assembly of the observation deck to begin!
(c) Bernhard Rennhofer
The Tower Shaft - The Observation Deck
Instead of being circular, the observation deck, mounted 150 meters above ground, has the shape of an equilateral triangle.
Its support structure consists of 24 steel radial beams, resembling a truss framework. These beams were lifted to the top of the tower using a small crane and were directly attached to the shaft. After installation, they were encased in concrete at both ends—and to this day, these embedded beams remain visible on the underside of the deck.
(c) Bernhard Rennhofer
The Tower Head – Engineering Meets Spectacular Views
1 | Architecture & Function in Perfect Harmony
The tower head is the centerpiece of the Donauturm, seamlessly combining architecture with sophisticated technology. It houses not only the restaurant and café but also practical facilities such as a central kitchen and restrooms.
(c) Bernhard Rennhofer
The Tower Head – Engineering Meets Spectacular Views
2 | The Unique Rotating Mechanism
To ensure that all guests enjoy the best possible view, a rotating platform was developed. Instead of facing just one direction, the entire restaurant and café floor rotates around the tower.
(c) Bernhard Rennhofer
The Tower Head – Engineering Meets Spectacular Views
3 | How Does the Rotation Work?
The rotating platform rests on a steel framework that moves on special rollers. These rollers drive the platform, allowing it to rotate independently, without affecting the tower shaft.
(c) Matthias Schmitt
The Tower Head – Engineering Meets Spectacular Views
4 | Three Different Speeds
The rotation operates at three speeds:
Fast: One full rotation in 22.5 minutesMedium: One full rotation in 26 minutes
Slow: One full rotation in 45 minutes
The Steel Mast – The Crown of the Donauturm
1 | More Than Just a Design Element
The steel mast at the top of the Donauturm is not just a visual landmark—it also serves an important function. In addition to the prominent logos, it houses a police radio system and various weather instruments.
The Steel Mast – The Crown of the Donauturm
2 | Height & Tapered Structure
The 70-meter-high mast tapers towards the top, similar to the tower shaft:
Base diameter: 2.50 metersRemains constant up to 232 meters
Narrows to just 1 meter at the top
The sheet metal thickness also varies, from 18 mm at the base to just 8 mm at the top.
(c) Bernhard Rennhofer
The Steel Mast – The Crown of the Donauturm
3 | A Technical Challenge During Installation
Instead of lifting the mast as a single piece, it was assembled in sections using a crane and welded at the top of the tower shaft. A special working platform extended beyond the observation deck, allowing the safe transport and installation of the mast sections.
(c) Matthias Schmitt
The Steel Mast – The Crown of the Donauturm
4 | Smart Design to Reduce Wind Oscillations
The tip of the steel mast is equipped with sheet metal strips in a spiral shape. These help to minimize vibrations caused by strong winds, ensuring stability even in extreme weather conditions.
(c) Bernhard Rennhofer
Warmth at High Altitudes – A Challenge of the Past
As early as the 1960s, heating the gastronomy areas at 160 and 170 meters posed a remarkable technical challenge. Wind, cold, and the rotating platforms demanded creative solutions. Warm air was channeled through central ducts to the upper levels – an innovation that made it possible to dine comfortably in the Turm Restaurant, even during winter.
Rotating Comfort Zones
Heating the rotating café and restaurant levels was particularly demanding. Special air ducts in the base zone transported warm air to the moving platforms. The technology at the time was sophisticated – but with rising expectations for energy efficiency and comfort, it eventually reached its limits.
Hoval Delivers Cutting-Edge Heating Technology
In 2017, the heating system was completely modernized. Two Hoval Max-3 gas boilers now deliver reliable warmth with 700 kW of output, controlled by the intelligent TopTronic E system. A heat exchanger system supplies the rotating platforms with 80°C warm air – efficient, robust, and future-ready. Even at sub-zero temperatures, it's pleasantly warm 170 meters above the ground.