The largest steel frame in my portfolio: seven 7-metre cross frames, a 20° roof and five rows of modules down the slope. Model, calculation and a complete drawing package for fabrication and erection.
A canopy over a car park with the roof fully covered by 2382 × 1134 mm modules: five rows down the slope, columns at 7 metres, three columns per frame and the lowest module edge 2.3 m above ground.
My job: tell whether this can be built from thin-walled galvanised sections at all, check the loads, and then take the structure to drawings the shop can cut, drill and erect from.
42 metres of roof carrying almost 6.2 tonnes of modules, with cars parked underneath.
Thin-walled sections instead of hot-rolled steel. Beams, columns and purlins are built from 2.5 mm galvanised C-sections placed back to back as built-up I-sections. Light, but sensitive to local buckling, so every member was checked on its own.
Snow and wind on an open canopy. An open mono-pitch roof works in both pressure and uplift. The most loaded beam over the middle column reached 98 % of its capacity; purlins are restrained against uplift.
Longitudinal stiffness. The frames stand only in their own plane. Along the canopy the structure is held by Ø8 cables with turnbuckles and braces between columns.
Foundations in uplift. A column base sees up to 78 kN compression and up to 37 kN uplift. 84 M24 × 1500 anchor studs are cast into a continuous slab with a thickening under every base.
Seven identical frames, staggered bolted splices where the bending moment is lowest, and standard strut under the modules.
2×C250 rafters and columns as built-up I-sections with a packer, 2×C200 purlins, S350GD galvanised steel
Purlin splices are staggered at the contraflexure points instead of over the columns
76 galvanised 41 × 41 × 2.5 struts, 6 m long, under the modules; modules clamp onto them
Bracing: horizontal and inclined braces in the frame, longitudinal Ø8 DIN 3055 cables with M12 turnbuckles
C20/25 concrete: a 200 mm slab under the whole canopy and 700 × 700 thickenings at the bases, M24 DIN 975 anchors
Load-bearing frame of 2.5 mm galvanised S350GD C-sections in built-up profiles; black steel only for packers, gussets and base plates. Fasteners: DIN 6921 bolts, class 8.8, M12 to M20, DIN 985 nuts, DIN 125 washers; Ø8 DIN 3055 cables with turnbuckles, thimbles and clamps.
Model envelope 42 858 × 11 093 × 6 869 mm. Two variants exist: plain and with a 1200 mm billboard frieze along the whole front (38 sheets).
The package: bill of materials, frame assembly drawings, a drawing for every part with bolt holes, plates for cutting, concreting and anchor layout, cable and module installation.
The client got the key answer before fabrication: the structure can be built from thin-walled sections, and it is clear which members are at the limit. The same project then went on to drawings.
The package is ready for production without recalculation: every part has a drawing, every joint has its fasteners in the bill of materials, and the foundations have an anchor layout.
Send a sketch or a photo, and within 24 hours I'll tell you how long it takes and what I need from you.
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