Design of Steel Structures - GATE Civil Construction Materials & Management

General design consideration for structural fasteners are as follows:

Where t = thickness of thinner plate
Calculation:
Given data;
t = thickness of thinner plate = 20 mm
The In-line gap (millimeter) of these binder should be
= 32t or 300 mm, whichever is less
= 32 × 20 mm or 300 mm, whichever is less
= 640 mm or 300 mm, whichever is less
Hence, The In-line gap (millimeter) of these binder should be 300 mm.

Steel design, or structural steel design, is a branch of structural engineering that deals with the design of steel structures. A steel structure is made up of structural members made of steel that have standard cross-sectional profiles, chemical compositions, and mechanical qualities.

The properties of structural steel, as per clause 2.2.4 of IS 800:2007, for use in design, may be taken as given in clauses 2.2.4.1 and 2.2.4.2 of the code.

Since, 
1 kg = 10³ g
Therefore, 7850 kg/m³ = 7850 × 10³ g/m³

The limit state method is commonly used to design steel buildings and their components. When the limit state method isn’t feasible, the working stress method can be employed.

Economical depth of plate girder (D): 
Compressive member are always based function of their depth. The depth at which the weight of girder is minimum is its economical depth.
For riveted plate girder, 
For welded plate girder, 
where M=Maximum bending moment,
σ_b = Permissible bending stress
If the depth of girder is less than 750mm, it is called shallow plate girder.
If the depth is more than 750mm, it is called deep plate girder.
∴ Economical depth of a plate girder corresponds to minimum weight.

Shear lag:

• The phenomenon of producing higher stresses near the junction of a web and lower stresses at points away from the web of a steel beam is known as shear lag.
• Shear lag occurs due to the non-uniform distribution of forces across the cross-section of the beam.

Slope: Slope is the incline of the roof expressed as a ratio of the vertical rise to the horizontal run, where the run is some portion of the span/

Roof Trusses:

• They are economical for spans more than 6 m.
• The pitch of a roof truss (Rise/Span) should be 1/4 to 1/6 to its slope for proper drainage and slope = 2 times pitch .
• The spacing of roof trusses is kept 1/3 to 1/5 of the span.
• Roof trusses usually require very light members.
• A minimum angle section ISA 50 × 50 × 6 mm should be provided to avoid damage during transportation.
• The gusset plate should be at least 6 mm thick and at least 2 rivets should be used to connect any member to it.