Gersthofen, 22 October 2018. A car swinging upside down suspended on only two sheets of super-thin glass: "Gravity" is showcasing the potential in glass processing, adhesives, high precision engineering and manufacturing in a highly innovative, efficient and aesthetic design.
Two sheets of thin glass elegantly bonded to stainless-steel edge strips are suspended from a tripod structure which holds the swinging car very close over a podium. The glass sheets are 1 x 2m, composed of two 2 x 2mm heat-strengthened laminated glass panes. The load bearing capacity of this visually and physically light structure is impressive.
The team at Define Engineers relies on state-of-the-art engineering methods to determine the behavior of the 1.5 t car pendulum as it swings. A simulation called Non-linear Transient Dynamic FE analysis captures the hanging and dynamic nature of the system. the results are used to design all components of the exhibit. The thin glass stretches under the dynamic load of 1.35 t, which eliminates all bending and ensures that the glass behaves as a membrane - the most efficient way to carry load.
A key feature of Gravity is the transparent connection between the glass and the stainless steel brackets
The permanent stress in the TSSA layer, estimated at about 0.6 N/mm², is further increased by the dynamic effects of the swinging car to ~0.7 N/mm². seele, the façade construction specialist, carried out structural performance tests to confirm the TSSA reliability utilising samples of thin glass with a size of 400 x 600 mm. The test TSSA bonding area of 300 x 40 mm had to transfer a permanent load of 4.5 kN resulting in local peak stresses of about 0.6 N/mm². The short- and long-term tests were successful with an ultimate load capacity of 53 kN.
The size and optimum shape of the stainless steel connections were designed and manufactured by seele. The special competence lies in the minimal design of the connections, the bonding and the aesthetically high-quality execution. The stainless steel brackets are milled and a fork is welded to the bracket. In the last fabrication step, seele is polishing the metal surface. The bracket is designed to transfer the dynamic design load of 13.5 kN.
The thin glass with a size of 1 x 2m is laminated and the metal stripes are bonded to the glass. seele was also responsible for the preparation of the car, the design and manufacturing of the suspension points on the vehicle.
"Gravity" - a team effort
Collaboration is what makes intense design and construction efforts like this possible. It arises when working relationships turn into friendships, when equal interests form concepts and find their expression in the finished work. Knowledge and confidence gained in small projects may find application at a larger scale. That is why the understanding of glass is strengthened on a theoretical and practical level and thus becomes part of the building culture. "'Gravity' is an exemplar of fully-integrated design development. This is a process that evolves for fast production times, sidestepping established design hierarchies, while still producing innovation and high quality. A high level of trust and technical knowledge, as well as a respect for the value of good design, is required from all parties – a true team", says Luke Lowings from Carpenter | Lowings Architecture & Design.
The "Making-of" of the whole project can be found on our YouTube channel.