How Do Tensile Structures Work and What Materials Can ...

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Let us return to the first architecture class on structures and the classification of structural efforts. In most structures, whether natural or man-made, compression forces are the primary actors. These are efforts undertaken with equal and opposing loads, applied in the interior of the structure, which tend towards the shortening of the piece in one direction - or compressing it, as the name indicates. It is not difficult to find examples of this: for example, a stone wall or a wooden log can resist the weight of a covering through internal compression efforts that are inherent to each material. Tension efforts, on the other hand, tend to lengthen components in the direction of the applied force of action. Steel, for example, is a material with good tensile strength. It is used in reinforced concrete precisely in the parts where the piece is in traction. But it is also possible for a structure to only have tensile parts, as is the case of membrane, tensioned, or tension structures, which consist of surfaces pulled by the action of cables or ropes in which the masts absorb compression efforts.

According to Robert Cartes, "Tensile structures are anticlastic forms, characterized by flexible fabric membranes which are supported by cables, a structural steel framework and foundations." The first examples go back to very rudimentary architectures of our ancestors, with animal skins stretched out to create shelter. As this article demonstrates, the history of tents highlights the ingenuity and adaptation of humans, with examples such as the "tipi" tents of Native Americans or the Bedouin Black Tents, built with local resources and knowledge. There are many examples throughout history, from simple tents to large circus structures, including research that shows their use even in Rome's Coliseum, which was used to protect the public from rain.

However, this technology quickly evolved during the twentieth century, with large contributions from the architect Frei Otto, who was fascinated by experimentation and had already applied the concepts of sustainability long before this term became popularized. According to a retrospective of his career, produced by MoMA, "Drafted into the German Air Force, he served as a pilot during the Second World War. In a prison camp at Chartres he was put in charge of a reconstruction crew attempting to repair bridges and buildings without any construction materials. His methodical ingenuity led Frei Otto to structural solutions which, he discovered later as a student, were not common engineering practice but genuine innovations." Otto developed extensive trials on tensioned structures and made important and imposing works, such as the Munich Olympic Stadium. "Frei Otto's theory of minimal structures has been summarized as an attempt to achieve, through maximum efficiency of structure and materials, optimum utilization of the available construction energy. As a consequence he sees the architect less as a designer than as a manager of this energy, which is the sum total of material and labor involved in construction."

Another important name in this area was another German, Horst Berger, who developed mathematical calculations that allowed this process to be translated into the construction structure. Berger's works include the Haj terminal in Jeddah, Saudi Arabia, completed in and the Great Hall at Denver International Airport ().

Usually extremely sober structures with very few elements, including cables and frames generally made of steel, there are various options of materials that can be used for the membranes. These tend to be in constant development in order to increase their durability, ease of maintenance and the ability to withstand more strains. For exteriors, the most commonly used are the so-called "Structural Coated Fabric", which consist of an inner mesh coated by protective films that provide waterproofing, fire resistance and fabric colors. The most common materials are as follows:

Polyvinyl Chloride (PVC)

This is possibly the most commonly used material. According to a study developed by ArchitenLandrell, PVC has good resistance and maintenance capacity, and is more affordable compared to other options. However, it allows the least amount of light to be transferred from the outside to the interior.

Politetrafluorethylene (PTFE)

PTFE, an ethylene polymer plastic, is quite sturdy and durable. Nonetheless, it is the most expensive option and does not allow its disassembly and later reassembly. Due to its resistance to ultraviolet rays, it is widely used in extreme climates such as the desert or in very cold places.

Contact us to discuss your requirements of PVC Tensile Membrane Structure. Our experienced sales team can help you identify the options that best suit your needs.

Silicone-coated fiberglass (SiPE)

When a project requires a greater degree of translucency, this is the most recommended material. Its functional characteristics resemble PTFE, with a lifespan of about 35 years and good resistance to ultraviolet rays.

Ethylene Tetrafluoroethylene (ETFE)

ETFE (ethylene tetrafluoroethylene) is a fluorine-based plastic. This material has been widely used since the s, and allows for almost complete transparency. Mostly used in greenhouses, facades, pools, zoos, and others, it has a good fire resistance and can be easily recycled at the end of its useful life.

In addition, there is ongoing research to incorporate new features and improve the efficiency of these membranes. For example, to include photovoltaic cells in membranes, integrate artificial lighting and further improve thermal and acoustic qualities so that their use can be more widespread and therefore fulfilling increasingly demanding requirements.

See this My Archdaily folder for several examples of architecture with tensile structures.

Tensile structures are anticlastic forms, characterised by flexible fabric membranes which are supported by cables, a structural steel framework and foundations. With innovative advances in materials and engineering techniques, tensile architecture can be designed in a variety of styles, shapes and sizes.

The origins of fabric structures can be traced back at least 40,000 years where the remains of simple shelters constructed from animal skins draped on a wooden frame or large bones from nomadic people have been found. 30,000 years later, woven fabrics were first incorporated in tents. Historically, these simple tents differ in building materials and techniques, depending on the climate where constructed. The Native American tipi is considered a masterpiece in structural design and was constructed using buffalo skins over a cone-shaped wooden frame structure. 

Whilst the Native Americans were perfecting the cone design, nomadic desert tribes in Northern Africa and the Middle East, like the Bedouins, were developing &#;black tents&#;. Traditionally made from camel leather draped over tension ropes and supported by a series of poles, the black tents received their name from the black goat hair woven coarsely into a breathing membrane. The loosely woven cloth allowed for air to pass through, whilst providing shade and protection from the rain. This marvelous adaption of simple materials created natural ventilation inside the tent, a real innovation for the hot climate of the Saharan Desert. 

Historically, more complex fabric structures were predominately the craftsman&#;s trade and not the domain of the architects. This focus was to shift in the nineteenth and twentieth centuries as architects became inspired by technological breakthroughs in structural engineering.  

Horst Berger, structural engineer and designer known for his lightweight tensile architectural work, is credited for the introduction of tensioned fabric structures into modern architecture. In the s, Berger mathematically determined the shape of a tensioned fabric structure. Berger is responsible for some of the first, biggest and most beautiful tensile structures in the world, including the Haji Terminal at the King Abdulaziz International Airport in Saudi Arabia which incorporates 21 &#;tents&#; of white Teflon-coated fiberglass fabric suspended from pylons, accommodating up to 80,000 travelers at once.

DENVER INTERNATIONAL AIRPORT

One of Berger&#;s most iconic projects is the beautiful tensile membrane roof at Denver International Airport. Berger provided a specialised roof design and engineering to support Fentress Bradburn Architects for this project. The principle design concept was to incorporate forms and materials indigenous to the environment and culture of the Rocky Mountain region surrounding the airport complex, creating a unique feeling of space. Harmony between the interior and exterior was achieved through the fusion of two natural elements &#; form and light. The nine-acre roof with its dramatic peaks and valleys give it a unique shape emulating the profile of the Rocky Mountains.

On a practical level, the unique tensile membrane roof designed resulted in a cost-effective project with reduced construction time, durability and improved energy efficiency over traditional building materials and techniques. The double-layer lightweight Teflon® PTFE-coated fiberglass membrane roofs allow for a greater span than traditional roofing systems. PTFE was chosen because this fabric membrane is an extremely durable, weather resistant and highly sustainable material for roofing applications. It can be installed in climates ranging from the frigid arctic to the scorching desert heat.

TENSILE FABRIC STRUCTURES WITH J & J CARTER

The versatility of tensile architecture is what makes it so unique, allowing for the design of existing and practical roof forms that would be almost impossible with traditional building methods.

Working alongside the client's professional advisors, we can provide architectural solutions using the latest in fabric developments. With an in-house team of structural engineers, project managers, installers, designers, membrane fabricators and steel/aluminum fabricators, we provide a single source of supply for architectural fabric tent structures. 

Please contact us to learn more about our full array of unique, award-winning and location enhancing structures we have produced for a range of organisations.

The company is the world’s best Self Adhesive Fiberglass Mesh supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.