ScoreCardAIScoreCardAI
Civil EngineeringWBPSC AE · SSC JE · RRB JE

Steel Structures— Important Topics, Formulas & MCQs

Design of Steel Structures covers tension members, compression members, beams and their connections, governed by IS 800:2007 (Limit State Method). It is a high-yield, formula-driven subject where bolt/weld connection design and member capacity questions are common.

Try Free DemoStart Full Practice

Or solve the free Steel Structures MCQ practice set — real questions with answers & explanations, no login needed.

Important topics in Steel Structures

Bolted connections — shear, bearing, tension capacity
Welded connections — fillet & butt welds, throat thickness
Tension members — net area, efficiency, block shear
Compression members — buckling class, slenderness
Beams — laterally supported/unsupported, section classification
Plastic analysis & shape factor
Gantry girders & column bases
Pitch, gauge, edge distance (IS 800 limits)
Effective length of compression members
Connections eccentricity & lug angles
Must-know

Key concepts & formulas — Steel Structures

Fillet weld throat

Effective throat t = 0.7s (s = weld size). Strength = 0.7s·Lw·(fu/√3·γmw).

Shape factor

Ratio of plastic to elastic moment, Mp/My. Rectangle = 1.5, circle = 1.7, I-section ≈ 1.12–1.14.

Bolt value

Lesser of bolt shear capacity and bearing capacity governs the connection design.

Slenderness limits

Members carrying compression: KL/r ≤ 180; tension members ≤ 400 (IS 800).

Exam relevance

4–6 questions in AE/JE papers. Strongly overlaps with SOM (plastic analysis, buckling) — efficient to study together.

Study tip

Practise connection-capacity numericals; they recur almost verbatim in WBPSC AE and SSC JE papers.

Worked example

Sample Steel Structures MCQ

The shape factor of a rectangular cross-section is:

A. 1.0
B. 1.5
C. 1.7
D. 1.12
Answer: B. Shape factor = Zp/Ze = (bd²/4)/(bd²/6) = 1.5. (Circle ≈ 1.7, I-section ≈ 1.12–1.14, diamond = 2.0.)

Common mistakes to avoid

Mixing up shape factors — rectangle 1.5, circle 1.7, I-section ≈ 1.12, diamond 2.0.
Forgetting the effective throat of a fillet weld = 0.7 × weld size.
Using bolt shear when bearing governs (or vice versa) — the lesser value controls.
Slenderness limits: compression members ≤ 180, tension members ≤ 400.
Keep going

Related Civil Engineering subjects

Strength of Materials
RCC
Soil Mechanics
Foundation Engineering
Surveying
Fluid Mechanics
Solve WBPSC AE 2020 PaperView Pricing