The Future of Construction is Here: Inflatable Concrete
Have you ever wondered why large shell-shaped structures are rarely built? It’s because the construction of such structures require large and expensive supporting structures. This is what The Vienna University of Technology has been working on. They have developed a new construction method that doesn’t require any timber structures at all!
An overview of this method is as follows: First, a flat concrete slab will be allowed to harden on the ground, then an air cushion below the plate will be inflated, and therefore bending the concrete and completely forming a sustainable shell. Even large event halls can be built using this method. In Vienna, a first experimental structure has now been built by using this method. Here’s a video:
Source: YouTube, TU Wein
According to Professor Johann Kollegger, “It is similar to an orange peel, which is regularly cut and then flattened out on the table. We do it the other way around, starting with a flat surface and then bending it to a shell.”
Johann Kollegger and Benjamin Kromoser from TU Vienna develope this new construction method which has now been successfully tested on the Aspang Grounds in Vienna.
The Pneumatic Wedge Method
First, a flat slab will be created using standard concrete, while making sure to get the geometic shape exactly right. The slab will consist of several segments. Wedge-shaped spaces will be left between these segments, so that they will fit together perfectly once the structure is bent.
Once the slab hardens, and air cushion below is inflated. The cushion is made up of two plastic sheets that are welded together. At the same time, a steel cable is tightened around the concrete segments so that the concrete will be lifted up at the center, and pushed together from the outside.
To make sure that all the concrete segments are moving synchronously, they are connected with metal beams. In the experiment, the whole process was finished after two hours and the final height of the concrete structure was 2.9 meters.
When the concrete is bent, there are many tiny cracks that appear, but this isn’t a problem for the stability of the structure. We can see that in old stone arches,” Johann Kollegger said. “If the shape is right, each stone holds the others in place and the construction is stable.” At the end of the process, the structure can be plastered and will have just the same properties as stable as a concrete shell that is constructed the conventional way.
Article Source:
TU Wein
