Flat bars

There are many advantages to constructing with steel: the strength to weight ratio is excellent; metals join easily; efficient shapes are available; etc. These advantages create challenges that are best solved by a good understanding of how the metals actually perform in a structure. Structural steel shapes are suitable for a wide variety of uses. For example they are used in, building frames, roof trusses, floor framing, bench frames, gates, fences, cattle grids, scaffolds, tank stands, television towers, car trailers, rails, etc.

Most structural steel failures occur at connections, where a beam connects to a column, where a joist connects to a beam, etc. The Structural Engineer must design the steel members and give guidelines for the connections. The cold-formed sections are suitable for all types of welding such as spot welding, seam welding, projection welding, butt and groove welding, plug welding and arc welding. All of these are applicable to both uncoated and zinc coated sections.

Different shapes of structural steel (both hot-rolled and cold-formed) are available with specifications such as: I-beam’s, Z-Shape (half a flange in opposite directions), HSS-Shape (Hollow structural section such as square, rectangular, circular (pipe) and elliptical cross-sections), Equal angle, L-shaped cross-section, Channel ( [-shaped), Tee (T-shaped cross-sections), Rail profile (asymmetrical I-beam), Flanged T-rail, Bar (a piece of metal flat and long), Plate (metal sheets thicker than 6 mm or 1⁄4 in), Open web steel joist.

Some structural steel shapes such as I-beams have a high second moments of area, which can result in stiffness compared to cross-sectional area. It is very important for engineers to have understanding of the material and its limitations.

Flat bars (dimensions and properties)
Thickness	Mass in kg/m for widths in mm
mm	20	25	30	40	45	50	60	65	70	80	90
5	0.785	0.981	1.18	1.57	1.77	1.96	-	-	-	-	-
6	0.942	1.18	1.41	1.88	2.12	2.36	2.83	3.06	3.30	3.77	4.24
8	1.26	1.57	1.88	2.51	-	3.14	3.77	4.08	4.40	5.02	5.65
10	1.57	1.96	2.36	3.14	-	3.93	4.71	5.10	5.50	6.28	7.07
12	-	2.36	2.83	3.77	4.24	4.71	5.65	6.12	6.59	7.54	8.48
16	-	-	-	5.02	-	6.28	7.54	8.16	8.79	10.0	11.3
20	-	-	-	6.28	-	7.85	9.42	10.2	11.0	12.6	14.1
25	-	-	-	7.85	-	9.81	11.8	12.8	13.7	15.7	17.7
30	-	-	-	-	-	-	-	-	-	18.8	-
40	-	-	-	-	-	-	-	-	-	25.1	-

Flat bars dimensions and properties (continued)
Thickness	Mass in kg/m for width in mm
mm	100	110	130	150	180	200	250	300
6	5.18	4.71	-	-	-	-	-	-
8	6.28	6.91	8.16	9.42	-	-	-	-
10	7.85	8.64	10.2	11.8	14.1	15.7	-	-
12	9.42	10.4	12.2	14.1	17.0	18.8	-	-
16	12.6	-	16.3	18.8	22.6	25.1	31.4	37.7
20	15.7	-	20.4	23.6	28.3	31.4	39.2	47.1
25	19.6	-	25.5	29.4	35.3	39.2	49.1	58.9
30	23.6	-	31.6	35.3	42.4	47.1	58.9	70.6
40	31.4	-	-	47.1	56.5	62.8	78.5	94.2
45	39.2	-	-	-	-	-	-	106
50	-	-	-	-	-	-	-	118