Pre-tensioning: cutting the slack
Every fabric used in tensile structures has different stretch characteristics but critically they will not creep overtime.
At Base Structures, each roll of fabric is tested in our biaxial rig to the same design loads that the actual canopy will need to be tensioned out to. The amount the fabric stretches is fed back into how much the fabric pattern is ‘compensated’ in the patterning software; i.e. ‘shrunk’ in size so that it fits perfectly when tensioned out to datum.
This pre-tension ensures that even under snow load there is no ponding once the snow begins to melt.
The safety factor used for choosing the fabric weight is around 1:6 based on the maximum design loads.
