CE-801 Design of Steel Structures - May 2024 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
   aDesign a laterally supported beam of effective span $6m$ for the following data Grade of steel = Fe410 Maximum bending moment $M = 150kNm$ Maximum shear force $V=210kN$ Check for deflection is not required.
   How to answer

   • Calculate required plastic section modulus from $M$ using $f_y=250$ MPa for Fe410
   • Select suitable ISMB/ISLB section from steel table and check shear capacity for $V=210$ kN
   • Check web buckling / bearing and deflection exemption as stated
   • Summarize final section selection
2. 7 Marks
   bDesign a welded simply supported plate girder for a span of $30m$. The girder is loaded with uniformly distributed load of the intensity $35kN/m$ due to dead and live loads.
   How to answer

   • Compute factored UDL, maximum $M$ and $V$ for $30m$ span
   • Determine required depth, web thickness and flange plates per IS 800-2007
   • Design welds, stiffeners and check shear, bending and deflection
   • Give final plate girder cross-section
3. 7 Marks
   aCalculate the strength of a $20mm$ diameter bolt of grade 4.6 for the following case. The main plates to be jointed are $12mm$ thick. a) Lap joint
   How to answer

   • Determine bolt shear and bearing strength per IS 800-2007 for 20mm grade 4.6 bolt
   • Consider single shear plane in lap joint with 12mm main plates
   • Take minimum of shear, bearing and tearing strength as joint strength
4. 7 Marks
   bSingle cover butt joint, cover plate being $10mm$ thick.
   How to answer

   • Determine double shear / single shear planes for single cover butt joint
   • Calculate bearing strength governed by 10mm cover vs 12mm main plate
   • Take minimum strength as bolt strength
5. 7 Marks
   aDesign a double angle discontinuous strut to carry a factored load of $135 kN$. The length of strut is $3m$ between intersections. The two angles are placed back-to-back (with long legs are connected) and are tack bolted. Use steel grade Fe 410. a) Angles are placed on opposite side of $12 mm$ gusset plate.
   How to answer

   • Compute factored load and effective lengths for discontinuous strut
   • Assume trial double angle section and check slenderness and buckling class
   • Check design compressive strength per IS 800-2007 for angles on opposite side of gusset
   • Select tack bolt spacing and final section
6. 7 Marks
   bb) Angles are placed on same side of $12 mm$ gusset plate
   How to answer

   • Use same design load and length as part (a)
   • Modify effective length / radius of gyration for angles on same side of gusset
   • Check compressive strength and select section
   • Compare with opposite-side case
7. 7 Marks
   aDesign a seat connection for the factored beam end reaction of $110 kN$. The beam section is ISMB 250 @ $365.9 N/m$ connected to the flange of column section ISHB200 @ $365.9 N/m$ using bolted connection. Steel is of Fe410 and bolts are of grade 4.6.
   How to answer

   • Compute bolt shear, bearing and seat angle capacity for 110 kN reaction
   • Design seat angle, top cleat and number of bolts to ISHB200 flange
   • Check beam web bearing and stability
   • Give connection detailing
8. 7 Marks
   bWhat do you understand laterally restrained beams? Explain with diagram?
   How to answer

   • Define laterally restrained / supported beam and lateral-torsional buckling restraint
   • Explain provision of lateral supports to compression flange
   • Sketch plan/elevation showing restraints with neat diagram
9. 7 Marks
   aDesign an I section purlin for an industrial building, located at Chennai, with Galvanised iron sheets as the roofing material. Span of the truss $=13m$ Spacing of trusses $= 6m$ c/c Spacing of purlins $= 1.2m$ c/c Wind pressure intensity $= 2 kN/m^2$ Weight of GI sheets $=130N/m^2$ Grade of steel : Fe 410
   How to answer

   • Calculate dead load of GI sheets, live and wind loads on purlin spacing 1.2m
   • Resolve loads about strong/weak axes and compute $M_z$, $M_y$
   • Select I-section and check biaxial bending per IS 800-2007
   • Check deflection and final purlin size
10. 7 Marks
    bSketch and briefly explain any three failure patterns of bolted connection.
    How to answer

    • List any three modes: shear, bearing, tensile/tear-out, block shear
    • Draw neat sketches for each failure pattern
    • Briefly explain cause and IS 800 check for each
11. 7 Marks
    aDifferentiate between bearing type connection and friction type connection.
    How to answer

    • Define bearing type vs friction type (HSFG) load transfer mechanism
    • Compare on slip, strength, detailing and applications in table form
    • Mention IS 800 provisions for each
12. 7 Marks
    bA tie member consisting of an angle section ISA$100 \times 75 \times 8$, designed to transfer a factored axial load of $280kN$, is to be welded to a gusset plate of $10 mm$ thick, using $6 mm$ fillet weld. Design the weld, if the weld is provided on three sides by overlapping the angle on the gusset plate, at a shop. Also sketch the connection showing the weld lengths.
    How to answer

    • Compute weld strength for 6mm fillet shop weld and required total length for 280kN
    • Distribute weld on three sides considering eccentricity/centroid of angle
    • Calculate side and end weld lengths and sketch connection with lengths
13. 7 Marks
    aWrite a note on grouping of timber based on modulus of elasticity and extreme fiber stress as per IS 883: 1994.
    How to answer

    • State IS 883:1994 grouping criteria based on modulus of elasticity
    • State grouping based on extreme fiber stress / strength classification
    • Give group limits and examples
14. 7 Marks
    bAn ISLB 300 carrying UDL of $50 kN/m$ has effective span of $8 m$. This is to be connected to the web of girder ISMB 450. Design the framed connection using $20 mm$ black bolts.
    How to answer

    • Compute factored shear from $50$ kN/m UDL on $8m$ span
    • Determine bolt value for 20mm black bolts and number of bolts
    • Design web cleat angles and check block shear
    • Give framed connection detailing
15. 14 Marks
    Write a short note on :

    1. i)Types of roof trusses
    2. ii)Purlins
    3. iii)Profile of gantry girder section
    4. iv)Deflection limits of gantry girders
    How to answer

    • Briefly describe types of roof trusses with sketches
    • Explain purlins function and types
    • Describe gantry girder profile and deflection limits per IS 800