CE-801 Design of Steel Structures - Jun 2025 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 laced column with two channel sections placed toe to toe of length 10 m to carry an axial load of 750 kN. The column is restrained in position but not in direction at both the ends.
   How to answer

   • Select suitable channel sections for axial load 750 kN and effective length from end conditions.
   • Determine spacing toe-to-toe to satisfy slenderness about both axes.
   • Design lacing system: slenderness of lacing, inclination, flat size and connections.
   • Check overall column strength and detailing as per IS 800.
2. 7 Marks
   bExplain the failures of bolted joints.
   How to answer

   • Define bolted joint and types of loading.
   • List shear failure, bearing failure, tensile/tearing failure of plate.
   • Explain block shear, bolt shear/rupture and edge failure.
   • Sketch failure modes and preventive measures.
3. 7 Marks
   aDesign a grillage foundation with I-sections, for a column having a load of 5000 kN. Column is provided with a base plate of size 700 mm d7 800 mm. Take the bearing capacity of the soil as 200 kN/m$^2$. Assume any missing data.
   How to answer

   • Calculate required foundation area from load 5000 kN and SBC 200 kN/m2.
   • Select tiers of I-sections, spacing and length in both directions.
   • Check bending and shear in beam tiers and base plate.
   • Detail grillage with separators and assume missing data.
4. 7 Marks
   bWrite down the steps for the design of laterally supported beams.
   How to answer

   • List design steps: factored load, trial section, classification.
   • Check bending strength, shear and deflection.
   • Check lateral support condition and bearing.
   • Summarize detailing and checks per IS 800.
5. 7 Marks
   aDraw a neat sketch for the steel roof truss showing its various components. Also explain any ten of its components.
   How to answer

   • Draw neat steel roof truss showing principal rafter, tie, purlins, etc.
   • Label components clearly.
   • Explain any ten components: function and location.
   • Mention load transfer path.
6. 7 Marks
   bA tie bar 100 mm d7 16 mm is welded to another plate. It is subjected to a factored pull of 300 kN. Find the minimum overlap required if 8mm site fillet welds are used. Assume any missing data.
   How to answer

   • Compute factored tensile force 300 kN and weld strength for 8 mm site fillet.
   • Determine required weld length from shear strength of weld.
   • Calculate minimum overlap from weld length and tie bar width.
   • Assume steel grade and partial safety factors if missing.
7. 8 Marks
   aDesign a gusseted base for a column ISHB350 @ 710 N/m with two plates 450 mm d7 20 mm carrying a factored load of 3600 kN. The column is to be supported on concrete pedestal to be built with M20 concrete.
   How to answer

   • Calculate factored load 3600 kN and required base plate area on M20 pedestal.
   • Design base plate thickness, gusset plates and stiffeners.
   • Check column, welds/bolts and concrete bearing.
   • Detail ISHB350 with 450 mm x 20 mm plates connection.
8. 6 Marks
   bWhat is a pin connection? List some of the pin connections used in steel structure.
   How to answer

   • Define pin connection and free rotation concept.
   • Explain components: pin, plates, washers.
   • List examples: beam-column, truss, base, splice pins.
   • Mention applications in steel structures.
9. 7 Marks
   aDesign a single angle section for a tension member of a roof truss to carry a factored tensile force of 225 kN. The member is subjected to the possible reversal of stress due to the action of wind. The length of the member is 3 m. Use 20 mm shop bolts of grade 4.6 for the connection.
   How to answer

   • Determine factored tensile load 225 kN and reversal due to wind.
   • Select single angle section for net area and slenderness.
   • Design 20 mm grade 4.6 shop bolts for connection.
   • Check block shear and 3 m length criteria.
10. 7 Marks
    bDistinguish between laterally restrained and unrestrained beams.
    How to answer

    • Define lateral restraint and effective length concept.
    • Compare bending resistance, buckling behaviour.
    • Tabulate differences in design checks.
    • Give examples of each beam type.
11. 7 Marks
    aDesign an I-section Purlin for an industrial building to support a galvanized corrugated Iron sheet given: Spacing of the trusses : 6m Inclination of main rafter - 30$^\circ$ Spacing of Purlin =1.5m Weight of Purlin = 1.5m Weight of corrugated sheeting -130M/m$^2$ Live Load = 0.6 kN/m$^2$ Wind Load =1.8 kN/m$^2$ Yield stress of steel = 250MPa
    How to answer

    • Compute dead, live and wind loads on purlin from spacing and inclination.
    • Resolve loads about strong/weak axes for 30 degree rafter.
    • Select I-section for biaxial bending and check deflection.
    • Use steel yield 250 MPa and given weights.
12. 7 Marks
    bWhy steel is considered for structural applications as compared to cast iron and wrought iron?
    How to answer

    • List properties of steel: strength, ductility, toughness.
    • Compare with cast iron brittleness and wrought iron limitations.
    • Explain weldability, homogeneity and structural suitability.
    • Conclude why steel preferred for structures.
13. 7 Marks
    aExplain block shear failure.
    How to answer

    • Define block shear: tension + shear rupture planes.
    • Sketch typical block shear patterns.
    • Give design strength equations per IS 800.
    • Mention factors affecting block shear.
14. 7 Marks
    bA simply supported beam of span 6 m supports a reinforced concrete slab. The compression flange of the beam is restrained due to its connection with the slab. The beam is subjected to a dead load of 25 kN/m and an imposed load of 20 kN/m. Design the beam.
    How to answer

    • Calculate factored UDL from 25 kN/m dead + 20 kN/m imposed.
    • Determine max BM and SF for 6 m simply supported span.
    • Select beam section for laterally supported condition.
    • Check shear, deflection and flange restraint.
15. 7 Marks
    aCalculate the number of bolts required to connect two plates of 1120 mm d7 8 mm size in lap joint, to transmit a factored load of 120 kN. Use 12 mm bolts of grade Fe 410. Assume any missing data.
    How to answer

    • Determine bolt shear and bearing strengths for 12 mm Fe410 bolts.
    • Divide factored load 120 kN by bolt strength.
    • Account for lap joint single shear and missing data assumptions.
    • Report required number of bolts with layout.
16. 7 Marks
    bWhat is a Lug angle? Illustrate with sketch. Why lug angles are used?
    How to answer

    • Define lug angle and show sketch with connection.
    • Explain purpose: reducing connection length, shear lag.
    • Describe placement and design considerations.
    • State when lug angles are used.