General Information

Figure 1 shows a canopy roof.

Canopy roof.
Steel canopy roof with inverted pyramid columns.

Inverted Pyramid

Figure 2 shows the canopy roof.

Canopy roof.
Steel canopy roof with inverted pyramid columns.

The structure consists of four columns, four transverse beams (marked by the numbers), a tie beam, purlins, sag rods, and metal roofing sheets. The distance between the columns/transverse beams s ≅ 7 m, the purlin overhang a ≅ 4 m, and the width/transverse beam length l ≅ 11 m. The colums are made of a reinforced concrete part and a steel part, as shown in figure 3.

Column with inverter pyramid.
Inverted pyramid column.

The steel part consists of an inverted four-sided pyramid with two levels of perimetral beams and a vertical member, which is connected to the RC part by a base plate with stiffeners and anchor bolts. The steel part is made of circular hollow profiles, while the RC part has a circular cross-section. The base vertices A and B are connected to the transverse beams, while C and D are connected to the tie beam. The transverse and the tie beams are made of an I-section of the same size and placed at the same elevation. A schematic lateral view and a variant with a vertical steel column are shown in figure 4.

Lateral views.
Inverted pyramid Vertical column
Canopy roof lateral views.

The transverse beam is supported at three points (O, B, and A) in the used variant, while at two points (O and G) in the vertical steel column variant. O is the support at the RC structure of the building. Both columns have a height of about 8.5 m and the same spacing (s); the RC part is about 3 m.

  • Which variant will probably use fewer resources for the transverse beams?
    Which variant will probably use fewer resources for the columns?
    Does the inverted pyramid column have an RC part for efficiency reasons?
  • Figure 5 shows a schematic layout of the roof.

    Layout.
    Layout of a canopy roof with inverted pyramid columns.

    The tie beam is marked in red. Figure 6 shows a bottom view of the canopy roof.

    Canopy roof.
    Bottom view of a canopy roof.
  • What is the purpose of the tie beam in the purlin overhang region (a)?
    Can the tie beam between the transverse beams (s) be neglected?