Acrylic glass under the magnifying glass: investigating the causes after the Aquadom burst

Why? This question was asked by the public, media and experts a year ago. On 16 December 2022 in the early hours of the morning, the Aquadom, the world's largest free-standing cylindrical aquarium, which had previously been located in the Radisson Hotel in Berlin, burst. Prof Dr Christian Bonten, Head of the Institute of Plastics Technology (IKT), was called in as an expert to determine the cause.

The Aquadom was opened in December 2003 after several years of construction and consisted of an acrylic glass tank 16 metres high and 11.5 metres in diameter. It held around one million litres and housed around 1,500 tropical fish – until it suddenly burst a year ago.

The investigation of the incident required a detailed analysis. Around 700 pieces of debris from the Aquadom, weighing a total of around 90 tonnes, were collected by Prof. Christian Bonten and his team and subjected to a thorough examination. This work included labelling and mapping each individual piece of acrylic glass, measuring the parts and carrying out tear tests and chemical analyses. The experts had to put together a complex puzzle to understand how and where the Aquadom first broke.

A total of ten different hypotheses were tested, including those proposed by the public and the media: Was the aquarium shot at? Was it damaged with an ice pick or a hammer? Was there an earthquake or were vibrations caused by construction work nearby? Each of these speculations was carefully scrutinised and ultimately ruled out.

It could also be ruled out that the bursting of the acrylic aquarium was a failure of the plastic material. Even after 20 years, the same material would still be used for comparable aquariums.

At the end of the comprehensive investigations, there were three possible causes: a loosened adhesive seam after two decades of operation, possible notches caused by handling errors during the renovation work or stresses caused by the acrylic glass drying out after several months of being empty before it was refilled. It is no longer possible to determine which of these three causes was ultimately responsible for the bursting of the Aquadom.