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Monthly Archives: April 2016

During a particularly cold week in mid February (-20C to -30C) we were able to carry out the structural load test we had been hoping to conduct for this project.  The aim was to create a sheet of ice on the outer surface of the fabric and to release the cables to see if the folded geometry would support the loads of the ice and snow.  
Over the course of two nights during that week we applied 28 coats of water and were successful in creating an ice sheet with a varying thickness of ¼” – ½”.  On the morning of the third day we arranged to loosen the turnbuckles and slowly release the tension support of the upper cables, thereby releasing the support of the connecting “grab cables” that was pulling the fabric and interior cables into form.  Despite enormous cracking sounds and popping that was coming from the shattering ice that had adhered to the steel cables from the spray operation, the form of the fabric and ice shell did not budge.  Once fully released from the supports of the cables, it was clear that the building had not moved and it was fully supporting itself; Fabrigami was officially a free-spanning fabric reinforced ice shell structure spanning 28’ (wide) x 38’ (long) x 12’ (tall)!

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After the mass redesign to accommodate a completely new site; fabrication, construction and assembly was in full swing. With helping hands from 0812 Building Solutions the upper cable net was set into place and tightened to temporarily take up the weight of the future iced structure.

Next step was to have all hands on deck for the ‘Big Pull’. Lifting the building into place was always a part of the plan for site construction, we had been imagining it would be undertaken through an inverted marionette technique. We began by first establishing the position of the 2D fabric pattern relative to the upper cable net. For every hole in the fabric there was a 3/8” cable that corresponded to a U-clamp on the upper cable net. Once all 28 cables had been draped through their U-clamps they were fed back through the hole in the fabric. This allowed for all 17 individuals on site to begin pulling at the cables, resulting in a lift of the fabric. Having a uniform tensile force on all the cables helped direct the structure into its final form and allowed for a truly collaborative install. The last important part was to reach through each hole and clamp the cable to itself, giving the structure a form of permanence that would allow for icing. Yet still give us the freedom to losing the upper cable net to test the loading capacity, once iced.

Inherent to the construction and design detailing of the upper cable net structure was a wide tolerance range. Since we were unable to mimic the cable material and weighted iced fabric in the digital model, it was critical we had the opportunity to adjust or remove sections of cables if need be. Ultimately turnbuckles proved to be our best friend in this construction. They allowed us loads of room to adjust, tighten and release the fabric structure when we needed.

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Working together, for 10 days at the beginning of January, the team prefabricated several elements of the design in advance of the site fabrication.  The components included: the assembly and integration of the cable loops into the fabric, the cutting of the steel cables and the assembly of the cable structure.

Work was done in the FABLab, as well as in the largest room available in the Faculty – the main Centerspace of the John A. Russell building; where a tarp was laid down to accommodate the flat assembly of the steel cable system and the connection to the fabric.

The fabric panels were pre-sewn by a manufacturer in the city.  The fabric was then laid out flat in order to locate and position the holes through which the upper cable and lower cable structures would connect.  The 8” diameter holes were reinforced with steel cable loops sewn into place.

The second component was the fabrication of the cable net.  This included the cutting of specific lengths of cable, crimping the sleeves and finishing the ends with thimble loops. These lengths were then joined together at specific locations with a quick link.   The intention behind the prefabricated cable net structure was to create a system in which the length of the individual cable links were fixed, therefore having the advantage of being relatively easy to assemble and erect on site.  Due to the possibility of errors in the calculations and manufacture, and the desire to tension the net properly, a number of turnbuckles were also incorporated in specific locations, enabling the length of some of the cables to be adjusted on site.

The fabric and the cable net were connected together with small u-clamps to create the Fabrigami structure, prefabricated and ready to head out to the site.

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This year’s winter temperatures were unseasonably warm causing the Assiniboine and Red rivers to freeze at a much slower pace than previous years.  As a result we needed to select an alternate site to provide both solid grounding as well as site conditions that would allow us to create a strong cable net structure to raise our fabric shell.

Adjacent to our initial site there is a converted train bridge that has since become a pedestrian pathway for the Forks Park.  The bridge was designed with a large concrete counterweight which would allow it to be lifted allowing ships to pass underneath.  The existing steel framing and concrete structure acted as excellent anchor points for us to design a new cable system.  Because of the preliminary research in how to design a cable net system and develop an origami structure that was able to be shaped to suit a unique site, we were able to adapt to the new site constraints in short order.  The building form came about out of a negotiation of the skating path and walking trail that moved through the building as well as the new geometric boundaries set up by the new overhead cable net. The final building design proposed the creation of a 28’ wide, 38’ long, and 12’ high space enclosed by a folded cotton (96%) and spandex (4%) blended fabric origami structure.

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