Tensile Structures: Bending your design into shape
A tensile structure is a construction of elements carrying only tension and no compression or bending. Chances are you have seen them before, without even knowing that they were tensile structures
If you happened to watch the recent cricket matches between India and Bangladesh at the home of cricket, Sher-e- Bangla National Cricket Stadium, chances are you saw top angle camera shots looming over the media centre press box at the north end of the stadium. It is an unmissable sight at Mirpur.
Adorning the horizon are these fabric-like, atrium-shaped structures called tensile structures, a type of architecture that has not yet been widely adopted in Bangladesh by the general public.
Golam Morsalin Choudhury Rana, an architect who currently works for Tensile Architecture Bangladesh, was initially interested in tensile structures because of their undeniable visual appeal and economic viability. His fascination with the Sher-e-Bangla stadium's design drove him to pursue further education in the field of tensile architecture in Germany.
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At that time, he was working with Architect Dr Shabbir Ahmed, the designer of the entry porch of the British Council Dhaka, which was also the first known example of tensile architecture in Bangladesh.
After returning to Bangladesh, Golam Morsalin founded ALM Tensile Structure Ltd (now Tensile Architecture Bangladesh) with his partner Engineer H M Jahidul Islam, which has completed more than 150 projects since its inception.
In layman's terms, a tensile structure is a construction of elements carrying only tension and no compression or bending. The integration of the concept into the Bangladeshi consumer base was not an easy ride, and this was evident in Golam Morsalin's words when he spoke to The Business Standard at length regarding tensile architecture and its present-day application in Bangladesh.
"When we first started with ALM Tensile Structure back in 2015-16, the concept of tensile architecture was quite unfamiliar in Bangladesh. People were not aware of its variable applications," said Golam Morsalin.
Over time, ALM Tensile Structure worked in factories, with shade structures and lightweight structures. At present, the largest application of tensile architecture in Bangladesh is in the form of car park shades, rooftop and atrium shades, as well as shades used for protection against rain.
"There are a lot of places, such as restaurants, with usable spaces in open-to-sky rooftops and lawns, that struggle in the rainy season to bring in customers. The installation of attractive shading devices brings in more customers, as they provide alternate seating arrangements. We try to apply dynamic designs as opposed to traditional designs."
Not as costly as you think
The frenzy of Messi lifting his first World Cup is not fading anytime soon. But do you remember the time he lifted his much cherished first ever Copa America trophy? He did that at Brazil's Maracana Stadium. The stadium's roof structure is an example of beautifully crafted tensile architecture.
So is the Munich Olympic Stadium. Apart from stadiums and sports centres, tensile architecture has been applied on various landmarks worldwide, such as the Denver International Airport and The Millennium Dome in Greenwich.
For a developing country like Bangladesh, it takes time for foreign architectural applications to be adopted by the general people. Architectural firms such as Golam Morsalin's one face certain challenges in that regard.
"The main obstacle we encounter is the ideology that people in this region of the world hold. They search for affordable solutions. They begin comparing the prices with those of steel and concrete as soon as we give them an overview of the anticipated costs."
"It is true that tensile membranes are costlier than steel and other structures but then again, steel has less variety and is harder to deform. On the other hand, concrete is cheaper but the concrete structures end up being really heavy, whereas tensile structures are lightweight."
Glass can also be used in some spaces, but it is costlier and also involves safety calculations and hazards.
So is the use of tensile architecture in Bangladesh only restricted to people belonging to a certain status quo? A niche demographic, especially once the costs of such goods and designs cross a certain threshold.
"Not necessarily. As a matter of fact, when it comes to lightweight structures, tensile structures are actually the more economical option out there," said Golam Morsalin.
Morsalin went on to describe an experience with a particular project his company worked on at East Delta University in Chattogram, where the university originally wanted to use steel for the atrium-shaped design they had in mind.
Morsalin, however, found that using tensile membranes instead of steel would be less expensive, after further analysis and calculation. That is because tension fabric uses a lesser amount of steel membrane, which in turn reduces the cost.
Speaking of cost, the price is charged per square foot of area. But it is still dependent on other factors. The price generally ranges from TK 900-1,000 per square foot. The type of design, the membrane, and the position of the design, however, may all affect the prices (whether the design is on the terrace or in a cyclone-prone area). The membrane's thickness and quality might change depending on the situation. Therefore, depending on the circumstances, the price may fluctuate.
A myriad of advantages
Tensile architecture comes in handy as well when it comes to lightweight and rapid construction on large scale, such as disaster shelters, tent structures etc.
It is not just the simplicity of construction or the financial benefits that will entice new customers to purchase the products. In actuality, the aesthetics are equally important, if not more so.
Tensile structures can present a visually dynamic sight when used in open spaces.
Tensile Structures Bangladesh have taken this to a whole new level. They apply a concept of tensile architecture, called Double Curve Shape, something which was amusingly inspired from soap bubbles by the German Architect Frei Otto in the 1950s.
The core concept behind it, is the fact that there is minimal surface to work with. Hence there is minimal stress due to the mean curvature being zero. This in turn allows the creation of lightweight structures with dynamic shapes for visual aesthetics.
There are multiple examples of prominent structures involving tensile architecture spread throughout the country. And chances are you have seen or visited them before, without even knowing that they were tensile structures. The Radisson Blu Chattogram Bay, Sylhet International Cricket Stadium, and the Sir John Wilson School entry porch in Shatarkul, Dhaka, all flaunt applications of tensile architecture.
Tensile Structures Bangladesh is not the only player in the game. In the present field of tensile architecture in Bangladesh, other companies, such as Shadetech Bangladesh, are also coming up with picturesque structures. Shadetech worked on the Sylhet International Cricket Stadium and also designed the BRAC CDM Coffee Shop.
However, an aspect of trade that is presently exclusive to Tensile Structures Bangladesh is that they produce their own fabric for use in their own factories, while other companies mostly import them after customising the shapes from China.
For the average consumer, the use of tensile structures needs to bring pragmatic benefits to his or her lifestyle. In that context, Morsalin emphasised the wide array of benefits that tensile structures possess.
"The primary benefit and the selling point, if you may call it, is the lightweight material and the fact that tensile structures make economic sense as well. Moreover, it has the potential to provide a greater sense of thermal comfort as an exterior design material in comparison to steel," he said.
Steel contracts heat but the tensile membrane does not as much. That is because they use white fabric, which reflects heat up to 70 per cent. Moreover, tensile structures have fewer limitations, they can be deformed into a wide range of shapes. They are also movable, expandable and retractable.
"You could even fold it or roll it up when you are not using it. It is all the more convenient."
