Solar Mounting Structure Steel in Bangladesh

Galvanizing thickness and coating life

ISO 1461's minimum mean zinc coat is 55 micron on 1.5 to 3 mm steel, 70 micron over 3 to 6 mm. ISO 9223 puts first year C4 zinc loss at 2.1 to 4.2 micron per year. Coastal and industrial sites in Bangladesh can fall in C4 or C5. Rule of thumb: coating life is roughly zinc thickness divided by yearly loss. At 2.1 micron a year, an 85 micron coat lasts roughly 40 years; at 4.2, roughly 20. GBTL targets 85 micron on request, confirmed per section thickness.

How much steel per MW

A rooftop solar structure typically uses about 40 to 60 tonnes of steel per MW. A ground mount structure typically uses about 45 to 70 tonnes per MW. Treat both as typical ranges, not design figures. On those typical ranges, a 2 MW ground mount plant would need roughly 90 to 140 tonnes. Actual tonnage depends on the structure design, wind load and module layout. Send GBTL your bill of materials or drawings for a quote in MT.

Choosing posts and piles

The 76.1 mm OD round post comes in 3.2 mm wall for ground posts and piles. The 88.9 mm OD post comes in 3.2 or 4.0 mm wall, for designs that need a larger section. Both come in 6 m lengths. For torque tube structures, GBTL makes a 114.3 mm OD blank on request. The blank comes in 3.6 or 4.5 mm wall and 6 to 12 m lengths. All these walls fall in the ISO 1461 70 micron minimum band. Your structural engineer confirms post size and embedment depth.

Choosing purlins, rails and frames

C purlin 100x50x20 mm, in 2.0 or 2.5 mm wall, carries modules across the rafters. C purlin 120x50x20 mm, in 2.5 mm wall, has a 20 mm deeper web. Z purlin 150x65x20 mm, in 2.0 or 2.5 mm wall, is the deepest purlin in the range. On rooftops, 41x41 mm strut channel serves as module rail and bracing. SHS 40x40 to 75x75 mm, RHS 50x100 mm and RHS 60x120 mm suit rafters, legs and frames. Your structure designer sets the spans and picks the final sizes.

Delivery, cut lengths and MOQ

GBTL delivers factory direct from its Narayanganj mill to your site, by district, across Bangladesh. Standard sections come in 6 m lengths, and torque tube blanks in 6 to 12 m. Put the cut lengths you need in your quote request. Order quantities are in metric tonnes (MT). The minimum is 2 MT for standard sizes and 20 MT for a custom size, because a custom size needs a full coil run. GBTL supplies mill test certificates on request.

Padma Multipurpose Bridge

Large diameter spiral (SSAW) and LSAW pipe for foundation piling on the 6.15 km road and rail bridge.

Spiral Pipe (SSAW), LSAW Steel Pipe

Dhaka Metro Rail (MRT)

Large diameter structural and piling pipe for the capital's first mass rapid transit line.