CE-601 Structural Design and Drawing (RCC-I) - 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. 5 Marks
   aList the assumptions made in the design of compression members.
   How to answer

   • State IS 456 assumptions for axially loaded short columns
   • Linear strain, concrete crushing strain, steel compatibility
   • Minimum eccentricity and effective length considerations
   • Material safety and perfect bond assumption
2. 9 Marks
   bExplain about balanced, under reinforced and over reinforced sections with neat sketches as per limit state method.
   How to answer

   • Define balanced, under-reinforced, over-reinforced by steel ratio vs balanced
   • Neutral axis depth comparison with limiting depth
   • Failure modes: ductile vs brittle with strain diagrams
   • Neat sketches of strain and stress blocks for three cases
3. 14 Marks
   Design a singly reinforced section for a simply supported beam of effective span 5 m carrying an imposed load of 10 kN/m. Use M25 concrete and Fe 500 grade steel. Assume moderate exposure condition. Adopt working stress method. Design reinforcement for flexure and shear. Sketch the reinforcement details.
   How to answer

   • Compute design loads, BM and SF for 5 m span with 10 kN/m imposed load
   • Determine section size and effective depth by working stress method for M25/Fe500
   • Design flexural steel and check for shear, design stirrups
   • Sketch longitudinal section and cross-section with reinforcement details
4. 6 Marks
   aWith a neat sketch, explain the force components that participate in the shear transfer mechanism at a flexural-shear crack location in a reinforced concrete beam.
   How to answer

   • Sketch flexural-shear crack with free-body on either side
   • Identify components: aggregate interlock, dowel action, compression zone shear
   • Explain stirrup contribution and bond transfer
   • Summarize equilibrium of vertical and horizontal forces
5. 8 Marks
   bA simply supported beam of 6.5 m effective span is to carry a uniformly distributed load (dead load) of 20 kN/m including its self weight, and a live load of 30 kN/m. Design the beam for shear using Limit state method. Use M30 concrete and Fe 500 grade steel. Sketch the reinforcement details.
   How to answer

   • Compute factored UDL from 20 kN/m dead and 30 kN/m live for 6.5 m span
   • Calculate factored shear force and concrete shear strength for M30
   • Design vertical stirrups for excess shear per limit state method
   • Sketch reinforcement details with stirrup spacing
6. 14 Marks
   Design a rectangular isolated stepped footing for a column of size $450\text{ mm} \times 650\text{ mm}$ carrying an axial load of $4000\text{ kN}$. The S.B.C. of the soil is $400\text{ kN/m}^2$. Use M 30 grade concrete and Fe 500 grade steel. Assume severe exposure condition.
   How to answer

   • Determine footing size from 4000 kN load and 400 kN/m2 SBC
   • Check one-way and two-way shear and bending moment for stepped footing
   • Design main steel in both directions for M30/Fe500 severe exposure
   • Sketch plan and stepped section with reinforcement
7. 14 Marks
   A column $300\text{ mm} \times 450\text{ mm}$ has an effective length of $3.5\text{ m}$. It is subjected to an ultimate load of $1500\text{ kN}$ and an ultimate moment of $350\text{ kN-M}$ about its major axis. Determine the longitudinal and transverse reinforcement. Use M35 concrete and Fe 500 grade steel. Assume moderate exposure condition. Sketch the cross-section showing reinforcement details.
   How to answer

   • Check slenderness and eccentricity for 300x450 mm, 3.5 m column
   • Use interaction chart / equilibrium for Pu=1500 kN and Mu=350 kN-m
   • Design longitudinal steel and lateral ties for M35/Fe500
   • Sketch cross-section showing bar positions and ties
8. 14 Marks
   Design a staircase flight for an office type building to suit the following data: Height between floors = 4 Mid landing is cantilevered out and the width is 1.5 m Tread = 300 mm and rise = 150 mm Adopt M-20 grade concrete and Fe-415 HYSD bars Sketch the details of reinforcement in the stair flight
   How to answer

   • Compute rise, going, waist slab thickness and loads for office stair
   • Calculate design moments and shear for flight with cantilever landing
   • Design main and distribution steel for M-20/Fe-415
   • Sketch flight reinforcement details in plan and section
9. 14 Marks
   Design the slab for a hall $7.5 \times 27$m. The slab is supported on RCC beams of $300$mm wide and spaced at $3$m c/c. The LL on the slab may be taken as $2.75$kN/m². Account for floor finishes and light partitions. Use M30 concrete and Fe 500 steel. Assume mild condition and sketch the details.
   How to answer

   • Determine one-way slab panels from 3 m c/c beams for 7.5x27 m hall
   • Compute dead, finishes, partition and 2.75 kN/m2 live loads factored
   • Design slab thickness and main/distribution steel for M30/Fe500
   • Sketch slab reinforcement details with beam supports
10. 5 Marks
    aExplain about the balanced section as per working stress method and limit state method for design of reinforced concrete structures.
    How to answer

    • State WSM balanced neutral axis using modular ratio
    • State LSM limiting neutral axis and steel ratio
    • Compare stress blocks and failure criteria
    • Conclude differences in safety and economy
11. 9 Marks
    bDetermine the moment of resistance of a doubly reinforced concrete beam section, 300 mm wide and 400 mm effective depth, reinforced with 2 bars of 16 mm diameter in compression zone and 3 bars of 20 mm diameter in tension zone. Determine the moment of resistance of the section. Use M 25 grade concrete and Fe 500 steel.
    How to answer

    • Compute Ast tension from 3-20 mm and Asc from 2-16 mm
    • Determine neutral axis depth and check vs limiting depth for M25/Fe500
    • Calculate lever arm and moment of resistance
    • State whether section is under/over-reinforced