General Information

Figure 1 shows a steel canopy roof.

Canopy roof.
Steel canopy roof

Wind Load

Figure 2 shows the roof structure viewed from below.

Canopy roof.
Steel canopy roof structure viewed from below

The steel structure consists mainly of transverse and longitudinal beams, purlins, diagonal roof braces, four suspension rods with a square hollow cross-section, and metal roofing sheets. Figure 3 shows the canopy roof viewed from the side.

Canopy roof.
Steel canopy roof with four suspension rods

The length l ≅ 4.5 m, and the width b ≅ 4 m. The transverse back beam and the suspension rods are connected to the reinforced concrete structure of the building. The suspension rods have two different inclination angles (α1 and α2) and converge toward the external longitudinal beams. Figure 4 shows a schematic partial three-dimensional view of the structure.

Three-dimensional view.
Three-dimensional structural drawing of a steel canopy roof
  • Is the above shown suspension rod arrangement required for structural efficiency reasons?
  • Figure 5 shows a variant with two suspension rods.

    Two suspension rods variant (three-dimensional view).
    Three-dimensional drawing of a steel canopy roof with two suspension rods

    Each suspension rod is made of a single steel wire rope. The remaining roof structure equals the used variant.

  • Assuming that the canopy roof has a mass of 400 kg, what are the main structural problems?