General Information

Figure 1 shows the construction site of a commercial building extension.

Commercial building extension.
Commercial building extension


Figure 2 shows a schematic cross-section of the structure.

Schematic cross-section of a commercial building extension

The new steel structure consists mainly of columns, beams, purlins, and metal roofing sheets. The continuous I-beam has 5 supports (A to E). The overhang m ≅ 2.5 m, the span s ≅ 12 m, and the span n ≅ 10 m. Figure 3 shows the span s region.

Span s region.
I-beam span

The I-beam height h ≅ 15 cm. Figure 4 shows the span s region viewed from below.

Span s region.
I-beam and purlin span

The purlin span p ≅ 5 m, while the purlin span q ≅ 9 m. The finished building extension includes a suspended ceiling with gypsum boards, as shown in figure 5.

Suspended ceiling.
Roof and suspended gypsum ceiling
  • What are some possible remarks on the I-beam size?
  • I-Beam to RC Structure Connection

    The I-beam between supports A and B is shown in figure 6, while the connection to support A is shown in figure 7.

    I-beam of a commercial building extension
    I-beam to support A connection.
    Connection between I-beam and the reinforced concrete structure

    The connection consists of an end-plate and four anchor bolts. The end-plate has two empty holes and a broken corner. The anchor bolt layout is asymmetric, and two adjoin the base plate.

  • How efficient is the connection?
    What are the main problems?
  • Purlins

    Figure 8 shows a roof sector viewed from below.

    Steel roof structure sector: I-beam, purlins and metal roofing sheets

    A purlin consists of a built-up section made of two side-by-side placed rectangular hollow profiles that are welded together as shown in figure 9.

    Two side-by-side connected steel profiles
  • Does the weld seam layout affect the uni and/or biaxial bending strength of a purlin?
    What are some possible reasons for using the above shown purlin type?
  • Metal Roofing Sheets

    Figure 10 shows a roof sector viewed from below.

     Metal roofing sheet with a hole

    There is a hole in the metal roofing sheet.

  • What are some possible causes of the hole?
    What are the main consequences?
  • External Columns

    Figure 11 shows a front view of two external columns (E).

    External columns (E).
    Steel columns of a commercial building extension

    Enlarged view 1 is shown in figure 12.

    Enlarged view 1.
    Steel column with a circular hole in the top-end web region

    The H-shaped column has a circular hole in the top-end web region.

  • Does the hole affect the design of the column and/or transversal beam?
  • Figure 13 shows an RC slab connection.

    Column to RC slab connection.
    Steel column base: base plate, weld seams, and anchor bolts

    The connection consists of a base plate and four anchor bolts. The column center is away from the base plate center, causing a column sector to protrude out of the base plate.

  • What are the main problems?