General Information

Figure 1 shows the construction side of a commercial building.

Commercial building.
Construction side of a commercial building with CFS trusses

Long-Span Cold-Formed Steel Trusses

Figure 2 shows the building.

Commercial building.
Main measurements of a commercial building with CFS trusses

The roof structure consists of cold-formed steel (CFS) raised tie trusses, purlins, and metal roofing sheets, while the columns and cross-braces are made of hot-formed steel (HFS).
The span s ≅ 20 m, the tie beam length l ≅ 12 m, the raise r ≅ 1 m, the roof pitch angle ɑ ≅ 8°, and the truss spacing ≅ 3.5 m. Figure 3 shows a front view of a truss sector.

CFS raised tie truss.
CFS truss  with eccentric nodes

The truss members are made of two back-to-back lipped channels, while the nodes consist of bolted gusset plates. The inclination angle of diagonal one with respect to the tie beam ≅ 16°, while the inclination angle of diagonal two ≅ 6°. Eccentric truss nodes are noticeable. Figure 4 shows a front view of the tie beam to rafter connection.

Tie beam to rafter connection.
Rafter to tie beam connection of a CFS raised tie truss

Figure 5 shows a partial three-dimensional view of the structure.

CFS raised tie trusses and HFS columns.
Three-dimensional drawing of a commercial building with long-span CFS trusses
  • What are some possible reasons for using CFS trusses instead of HFS trusses?
    What are the main structural problems of the obove shown CFS raised tie trusses?
  • Figure 6 shows a partial three-dimensional view of a long-span CFS portal frame variant.

    CFS portal frames.
    Three-dimensional drawing of a commercial building with long-span CFS portal frames
  • What are the main pros and cons of the two variants?