CE-801 Design of Steel Structures - May 2026 Question Paper

Under each question, How to answer lists the points an answer should cover, outlined by CampusPrep from the syllabus. Check the details against your textbook.

1. 7 Marks
   aExplain the limit state method and section classification used in steel structure design.
   How to answer

   • Define limit state method - ultimate and serviceability limit states
   • List partial safety factors for loads and materials per IS 800
   • Explain section classification - plastic, compact, semi-compact, slender with b/t limits
   • Role of classification in moment capacity and design
2. 7 Marks
   bA fillet weld of size 8 mm and length 150 mm is subjected to a factored load of 120 kN. Determine the design strength of the weld joint.
   How to answer

   • Calculate throat area $A = 0.7 \times s \times l$
   • Design strength formula $P_{dw}=l \times t_t \times f_u/(\sqrt{3}\gamma_{mw})$
   • Substitute $s=8\,mm$, $l=150\,mm$
   • Compare with factored load 120 kN and conclude adequacy
3. 7 Marks
   aDifferentiate between bearing type bolts and friction grip bolts. Explain failure mechanisms in bolted connections.
   How to answer

   • Define bearing type vs HSFG/friction grip bolts - load transfer mechanism
   • Comparison table - pretension, slip, shear, bearing
   • Failure modes - shear failure of bolt, bearing, tensile, block shear, slip
   • Sketches of failure modes
4. 7 Marks
   bA steel plate of width 180 mm and thickness 12 mm is connected by bolts using two holes of diameter 20 mm. Calculate the net sectional area of the plate.
   How to answer

   • Gross area $A_g = b \times t$
   • Deduction for holes $A_{ded}= n \times d \times t$
   • Net area $A_n = (b - n\times d)\times t$
   • Substitute $b=180\,mm$, $t=12\,mm$, $d=20\,mm$, $n=2$
5. 7 Marks
   aExplain the design considerations for compression members and the effect of slenderness ratio.
   How to answer

   • Define compression member - strut, column, buckling
   • Effective length, end conditions, slenderness ratio $KL/r$
   • Design compressive stress per IS 800 buckling curves
   • Limits on slenderness ratio and section selection
6. 7 Marks
   bA steel tie member consists of an ISA section carrying a tensile force of 200 kN. Determine the required gross area assuming permissible tensile stress as 150 MPa.
   How to answer

   • Required area $A = P/\sigma_{at}$
   • Substitute $P=200\,kN$, $\sigma_{at}=150\,MPa$
   • Compute $A$ in $mm^2$
   • Select suitable ISA section with area greater than required
7. 7 Marks
   aExplain lateral torsional buckling in steel beams and methods to improve beam stability.
   How to answer

   • Define lateral torsional buckling - compression flange buckling with twist
   • Factors - unbraced length, cross-section, loading
   • Critical moment concept
   • Methods to improve - lateral bracing, larger flange, box section, stiffeners
8. 7 Marks
   bA simply supported steel beam of span 5 m carries a uniformly distributed load of 30 kN/m. Calculate the maximum bending moment and identify whether the beam is laterally supported or unsupported in design consideration.
   How to answer

   • Maximum BM for UDL $M_{max}=wL^2/8$
   • Substitute $w=30\,kN/m$, $L=5\,m$
   • Compute $M_{max}$ in $kN$-$m$
   • Discuss laterally supported vs unsupported criteria - effective length and bracing
9. 7 Marks
   aExplain the design principles of plate girders and the role of stiffeners.
   How to answer

   • Define plate girder - when rolled sections inadequate
   • Components - flanges, web, stiffeners
   • Bending and shear design principles
   • Role of vertical, horizontal, bearing stiffeners
10. 7 Marks
    bA steel column carries an axial load of 900 kN. Determine the required area of base plate if allowable bearing pressure on concrete is $4\, N/mm^2$.
    How to answer

    • Required area $A = P/q_{allow}$
    • Substitute $P=900\,kN$, $q=4\,N/mm^2$
    • Compute area in $mm^2$ / $cm^2$
    • Select suitable base plate dimensions
11. 7 Marks
    aDifferentiate between laced columns and battened columns with neat sketches.
    How to answer

    • Define laced vs battened built-up columns
    • Comparison - lacing bars vs batten plates, shear transfer
    • Neat sketches of both systems
    • Advantages, applications and IS codal provisions
12. 7 Marks
    bDesign a slab base for a steel column carrying a load of 1000 kN assuming permissible bearing stress on concrete as $5\, N/mm^2$.
    How to answer

    • Required base area $A = P/q_{allow}$ with $P=1000\,kN$
    • Select plate size $L \times B$ exceeding required area
    • Check actual bearing pressure and cantilever projection
    • Determine plate thickness $t = \sqrt{2.5 w a^2/\sigma_{bs}}$
13. 7 Marks
    aExplain different types of roof trusses and criteria for their selection in industrial buildings.
    How to answer

    • List roof truss types - king post, queen post, Howe, Pratt, Fink, Warren
    • Sketches and span ranges
    • Selection criteria - span, load, roofing, economy, pitch
    • Industrial building application
14. 7 Marks
    bA roof purlin of span 4 m supports a roof load of 2.5 kN/m. Calculate the maximum bending moment in the purlin.
    How to answer

    • Purlin as simply supported beam $M_{max}=wL^2/8$
    • Substitute $w=2.5\,kN/m$, $L=4\,m$
    • Compute $M_{max}=5\,kN$-$m$
    • Note on biaxial bending if inclined
15. 14 Marks
    Write short notes on any two :

    1. a)Bracing systems in industrial buildings
    2. b)Web buckling and web crippling
    3. c)Shear lag in tension members
    4. d)Moment connections in steel structures
    How to answer

    • For each chosen topic give definition and purpose
    • Explain mechanism / codal provisions with sketches
    • Mention design checks / failures prevented
    • Applications in steel structures