CE-601 Structural Design and Drawing (RCC-I) - May 2022 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
   aBriefly explain the principles of limit state.
   How to answer

   • Define limit state concept - collapse vs serviceability
   • Principles: characteristic loads/strengths, partial safety factors
   • Probabilistic basis and design inequality: factored load <= factored resistance
   • Mention LSM assumptions for flexure
2. 7 Marks
   bDefine the following:

   1. i)Characteristics load
   2. ii)Characteristics strength
   3. iii)Partial safety factor
   How to answer

   • Define characteristic load as 95 percentile upper value
   • Define characteristic strength as 5 percentile lower value
   • Define partial safety factor for loads and materials and give values
   • Explain purpose in achieving target reliability
3. 7 Marks
   aDesign a R.C. beam to carry a load of $8\text{ kN/m}$ inclusive of its own weight on an effect span of $7\text{ m}$ keep the breadth to be $2/3^{rd}$ of the effective depth. The permissible stresses in the concrete and steel are not to exceed than $6\text{ N/mm}^2$ and $140\text{ N/mm}^2$. Take $m = 18$.
   How to answer

   • Compute design bending moment $M = wL^2/8$
   • Determine balanced section using $\sigma_{cbc}=6$, $\sigma_{st}=140$, $m=18$ by WSM
   • Solve for effective depth $d$ and breadth $b=2d/3$, adopt sizes
   • Calculate $A_{st}$, check shear, detailing and sketch
4. 7 Marks
   bA T-beam of flange width of $1600\text{ mm}$, Flange thickness $150\text{mm}$, width of rib is $350\text{ mm}$ has an effective depth of $600\text{ mm}$, the beam is reinforced with $6$ bars of $20\text{ mm}$ diameter. Determine the ultimate moment of resistance. Use M25 concrete and Fe415 steel.
   How to answer

   • Calculate $A_{st}=6\times \pi/4\times 20^2$
   • Determine neutral axis and check if section is under/over-reinforced T-beam
   • Compute $x_u$ and $M_{u}$ using M25 and Fe415 formulas
   • Report ultimate moment of resistance
5. 14 Marks
   Design a reinforced concrete slab for a room of clear dimension $6\text{m} \times 5\text{m}$. The slab is supported on walls of width $350\text{ mm}$. The slab is carrying a live load of $6\text{ kN/m}^2$ and floor finish is $1.5\text{ kN/m}^2$. Use M25 concrete and Fe415 steel. The corners of the slab are held down. Sketch the layout of the reinforcement.
   How to answer

   • Determine effective span, design loads with self-weight, floor finish and live load factored
   • Design two-way slab moments using IS 456 coefficients for corners held down
   • Calculate effective depth, $A_{st}$ in both directions and check shear/deflection
   • Sketch reinforcement layout showing top/bottom, torsional steel at corners
6. 14 Marks
   Design an isolated square footing for a column $450\text{mm} \times 450\text{ mm}$ reinforced with $8.25\text{ mm}$ diameter bars carrying a service load of $2000\text{ kN}$. The bearing capacity of the soil is $250\text{ kN/m}^2$ at a depth of $1.2\text{ m}$ below ground. the footing is restricted to $2\text{ m}$ in one direction. Assume M20 grade concrete and Fe415 steel for footing, M25 grade concrete and Fe415 steel for column. Draw to scale:

   1. i)Longitudinal section showing the reinforcement details.
   2. ii)The plan showing the reinforcement details.
   How to answer

   • Size footing from SBC $250\text{ kN/m}^2$ with 2000 kN service load respecting 2 m restriction
   • Check one-way and two-way shear and bending moment for depth
   • Design reinforcement and column-footing dowels with M20/M25 grades
   • Draw to scale longitudinal section and plan with details
7. 14 Marks
   Design the stairs for a public building, supported on wall on one side and stringer beam on the other side. The horizontal span of stairs is $1.4\text{ m}$. The risers are $120\text{ mm}$ and treads of $300\text{ mm}$. Use M15 mix.
   How to answer

   • Determine going, rise, effective span and design load for 1.4 m span
   • Calculate bending moment and effective depth using M15 mix
   • Design main and distribution steel for waist slab
   • Detail support on wall and stringer beam
8. 7 Marks
   aDesign a doubly reinforced beam of section $240\times500\text{mm}$ to carry a bending moment of $80\text{ kN-m}$. Assume clear cover at top a bottom as $30\text{ mm}$ and take $m=18$. Adopt working stress method. Assume the permissible stressed in the concrete and steel are not to exceed $5\text{ N/mm}^2$ and $140\text{ N/mm}^2$.
   How to answer

   • Compute factored moment and check if doubly reinforced needed for 240x500 mm
   • Determine $x_{u,max}$, $M_{u,lim}$ and compression steel using WSM with $m=18$
   • Calculate $A_{sc}$ and $A_{st}$ with 30 mm clear cover and $5$/$140$ stresses
   • Detail top and bottom steel with stirrups
9. 7 Marks
   bA rectangular beam is $200\text{ mm}$ wide and $400\text{ mm}$ deep up to the center of reinforcement. With the $3$-$16\text{mm}$ dia of Fe415 steel. Find the ultimate uniformly distributed load which the beam can carry safely over a span of $5\text{ m}$. Take M20 concrete.
   How to answer

   • Calculate $A_{st}$ for 3-16 mm and $M_u$ for M20/Fe415 rectangular section
   • Equate $M_u$ to $w_u L^2/8$ for 5 m span to get $w_u$
   • Convert to safe service UDL using load factor 1.5
   • Report safe uniformly distributed load
10. 14 Marks
    Design a short circular column of $6\text{ m}$ to carry an axial load of $250\text{ kN}$ if both ends of the column are fully restrained using

    1. i)Lateral ties
    2. ii)Helical steel
    How to answer

    • Check slenderness for 6 m height with both ends restrained for short column
    • Size circular section for 250 kN axial load per IS 456
    • Design longitudinal steel and lateral ties as per spacing rules
    • Design helical reinforcement as alternative with pitch calculation
11. 7 Marks
    aWrite down the design step with formulation of two-way slab with all necessary checks.
    How to answer

    • List steps: thickness, load, moments via IS coefficients, depth check
    • Design steel in both spans plus edge and corner torsion steel
    • Mention deflection, shear and development length checks
    • Give formulas for $M_x$, $M_y$ and $A_{st}$
12. 7 Marks
    bExplain the different types of footing with neat sketches:
    How to answer

    • Classify footings: isolated, combined, strap, raft, pile with definitions
    • Explain suitability based on load and soil conditions
    • Provide neat labelled sketches for each type
    • Compare load transfer mechanism briefly