Project overview
This project covered a group of miscellaneous steel structures in Al Ain for Ertifaa Aluminium & Glass LLC. Wrenze Steel carried out the structural design.
The model on this page shows one of them: two tensile fabric shade sails, each stretched between steel posts set at alternating high and low corners. The same package included an analysis of the fabric under load, an arched truss canopy with HDPE fabric on a single post, and a steel frame with a ladder.
Our scope
Our scope was the structural design of each structure. Firms that supply aluminium, glass and shading systems often need an engineer to design the steel that holds those systems up, and that was our role here.
For each item, the design covered:
- the loads from the fabric or cladding, with wind as the main case;
- the posts, beams and trusses that carry those loads;
- the connections and the base plates and anchors at ground level.
The structure
Tensile fabric shades behave differently from a roof. The fabric is pre-tensioned and twisted into a saddle shape, with its corners alternating high and low. That curvature gives the fabric its stiffness. Without it, the sail would flap in the wind.
The fabric pulls hard on its corners at all times, and wind adds more. The posts work as cantilevers from the ground, so the bending at their base is high, and the base plates, anchors and foundations must resist it. Posts are often raked outward, or tied back, to reduce that bending.
Arched truss canopies work another way. The curved trusses carry the fabric, purlins or rods brace them along the length, and a single post with a cantilevered truss leaves the space below clear for parking or walking.
Small structures like these are quick to build, but the forces at their supports are large for their size, so the base details deserve the most attention.
See more canopy and shade projects, read about our structural steel design service, or request a quote for your shade structure.
