inflatable concrete formwork for deer-crossing bridge at Koralmbahn, Austrian Federal Railways
in summer 2017, a crossing bridge for deers was built for the construction of a new railway line for the Austrian Federal Railways. The construction consists of an oval concrete shell built in a new process, developed and supervised by engineer Benjamin Kromoser.
Consequently, a 3200m2 large pneumatic cushion supplied by Pneumocell served as the concrete formwork.
The air cushion was first laid flat in a deflated state and then a 20cm thick layer of concrete was poured on top with crescent-shaped incisions.
As a result, the pneumatic cushion was slowly inflated and this raised the concrete slab so that it arched.
Therefore the crescent-shaped incisions closed and the curved concrete shell was stabilized with a steel ring around the perimeter and by applying another layer of concrete.
Doubly curved concrete formwork made of wood can only be produced with a great deal of effort. When using a pneumatic cushion, this effort is significantly reduced.