Airdomes are multipurpose, air-inflated indoor facilities primarily used for sports. Built by Polyned with quality materials like stainless steel cable-nets and coated textiles, these structures offer benefits such as natural light and sound insulation. Summum Engineering provided a comprehensive service, including creating a 3D parametric model to assess structural integrity and anchoring needs. Our model offered insights into the reaction forces at the anchoring points and aided in standardizing Polyned’s calculations, contributing to improved versions of their airdomes.
“Building with air”, it is an expression used to convey the optimal nature of using nothing more than air-pressure to inflate structures covering large surface areas, such as Polyned’s airdomes. Their airdomes, numbering about a hundred in the Netherlands, are versatile and cost-effective solutions for indoor sports and events. These structures can be used for a variety of activities, such as tennis, soccer, hockey, swimming, and more, allowing them to take place throughout the winter, regardless of the weather.
They are made with high-quality materials, including a stainless steel cable-net and high-performance polyester coated textiles, which are durable and lightweight. Additionally, Polyned’s air-inflated indoor sports facilities have several advantages over traditional ones, such as increased natural light, reduced noise, and customizable insulation. The company offers a full range of services, from design and fabrication to installation and maintenance, making them a one-stop-shop for airdomes, having produced them for over 50 years (!).
With the rise of artificial turf and modular sports flooring, these domes have recently become popular not only with tennis clubs but also with hockey, football and multi-sport clubs. Household names such as football clubs AZ, Manchester City FC, Southampton FC and Ajax are among Polyned’s references.
To further improve their airdomes, Polyned commissioned us to create a three-dimensional and fully parametric model for their designs. This model created a more detailed insight into the structural performance of their airdomes, and the reaction forces they produce around their perimeter, where they are anchored into the ground. The results were used to evaluate, improve and standardize their existing calculations and anchoring designs.
The air-inflated structure consists of multiple layers. A structural layer, a cable net, is covered with a base layer of coated polyester fabric on the inside. Unlike traditional structures, the cables and fabric are not directly connected. Instead, an overpressure is created inside the dome, causing the fabric to push the cables up to their desired position. The unique cable net and fabric design offer advantages such as reduced weight and material use, resulting in a more efficient and sustainable structure. Furthermore, an insulation layer and a protective and UV top layer are wedged between the cable net and fabric. Within the facets of the cable net, the fabric forms pockets that offer superior acoustic performance within the facility, by scattering sound.
To maintain the required pressure, specialized doors, or lock gates are used. These lock gates have their own ballast foundation that are separate from the main load-bearing structure. We provided an standardized calculation for several types of their lock gates, to check them against uplift, sliding and overturning under extreme weather conditions.
The geometry of the airdome was determined using a so-called form-finding algorithm. Based on the Polyned’s layouts for the cable-nets, the shape was generated by simulating the constant inner pressure acting on the fabric. An optimization procedure was used to maintain the desired height, for example 13 m for an airdome covering two hockey fields. The resulting shape was compared to point scans of an existing airdome , and found to be in close agreement. It was then analyzed for different wind load combinations from several standards. The cables and fabric were checked, and the reaction forces were provided to Polyned in order to design the ground anchors.
The knowledge from our work, as well as existing literature on airdomes, was then applied to further improve and standardize the engineering approach at Polyned, for the automated calculation and documentation of future airdomes, and obtaining building permission.
The use of computational design tools highlights the level of detail and precision involved in designing a complex structure like an airdome. By ensuring the structure is safe, stable, and efficient in its use of materials, these techniques help to create a functional and reliable design.
Diederik Veenendaal, Lena Woidt, Aitor Vadillo Barcelona | Summum Engineering