CE2306 Design of RC Elements Nov / Dec 2013 Important Questions

CE2306 Design of RC Elements Nov / Dec 2013 Important Questions

UNIT - I

1. A singly reinforced concrete beam is of width 450mm and effective depth 715mm. It is reinforced

with 8Nos.20mm mild steel bars. Assuming M20 concrete, determine its moment of resistance

according to the working stress method. Determine also the stress in steel when the beam is subjected

to the above moment.

2. Determine the reinforcement for a T beam with flange width = 1500mm, web width = 300mm,

thickness of slab = 100mm, effective depth 735mm, to carry a moment of 380kNm due to characteristic loads. Use M25 concrete and Fe 415 steel. Using Working Stress Design.

3. A singly reinforced concrete beam is of width 400mm and effective depth 615mm. It is reinforced

with 8Nos.20mm mild steel bars. Assuming M25 concrete, determine its moment of resistance

according to the working stress method. Determine also the stress in steel when the beam is subjected to the above moment.

4. Design a rectangular slab supported on its all four edges (600mm thick) over a classroom of size

4.8m x6.2m. Two adjacent edges of the slab are discontinuous and the remaining two edges are

continuous. A finishing surface of cement concrete of 20mm shall be provided over the slab. The slab

shall be used as classroom. M20 grade of concrete and HYSD bars shall be used. The unit weight of finishing surface concrete is 24KN/m3.

5. Design a rectangular beam section subjected to an ultimate moment of 120kNm. Use concrete M20 and steel Fe415. Adopt limit state method.

UNIT II

1. A rectangular beam has b=200mm, d=400mm if steel used is Fe 415 and grade of concrete is M25. Find the steel required to carry a factored moment of 12kNm.

2. Design of roof slab for an interior panel of size 5mx6m. Live load is 5.0KN/m2. Use M30 Concrete and Fe 415 Steel.

3. Design a simply supported R.C.C.SLAB for a roof of a hall 4mx10m (inside dimensions) with 230mm

walls all around. Assume a live load of 4kN/m2 and finish 1KN/m2.Use grade 25 concrete and Fe 415 steel.

4. A T beam continuous over several supports has to carry a factored negative support moment of

1000kNm. Determine the area of steel at supports if bW = 400MM, bfy =1600mm, Df = 100mm,

D=610mm, d' = 60mm, fck = 30N/mm2, f = 415 N/mm2.

5. A doubly reinforced concrete beam is 250mm wide and 510mm depth the center of tensile steel

reinforcement. The compression reinforcement consists of 4 Nos. of 18mm dia bars placed at an

effective cover of 40mm from the compression edge of the beam. The tensile reinforcement consists of 4Nos. of 20mm diameter bar. If the beam section is subjected to a BM of 85kNm, calculate the stresses in concrete and tension steel.

UNIT - III

1. A rectangular beam width b=350mm and d=550mm has a factored shear of 400kN at the critical

section near the support. The steel at the tension side of the section consists of four 32mm bars which

are continued to support. Assuming fck=25 and fy=415(N/mm2) design vertical stirrups for the section.

2. A reinforced concrete rectangular beam has a breadth of 350mm and effective depth of 800mm. It has a factored shear of 105kN at section XX. Assuming that fck=25, fy=415(N/mm2) and percentage of tensile steel at that section is 0.5percent, determine the torsional moment the section can resist if no additional reinforcement for torsion is provided. Workout the problem according to IS456 principles of

design for torsion.

3. A simply supported beam is 5m in span and carries a characteristic load at 75kN/m. If 6Nos. of

20mm bras are continued into the supports. Check the development length at the supports assuming grade M20 concrete and Fe415steel.

4. A rectangular RCC beam is 400x900mm in size. Assuming the use of grade M25 concrete and Fe415 steel, determine the maximum ultimate torsional moment at the section can take it.

(i)            No torsion reinforcement is provided and

(ii)           Maximum torsion reinforcement is provided.

5. A rectangular beam width b = 250mm and effective depth 500mm reinforced with 4 bars of 20mm

diameter. Determine the shear reinforcement required to resist a shear force of 150kN. Use concrete M20 and steel Fe415.

UNIT - IV

1. A rectangular column of effective height of 4m is subjected to a characteristics axial load of 800kN

and bending moment of 100kNm about the major axis of the n. Design a suitable section for the column so that the width should not exceed 400mm. Use the minimum percentage of longitudinal steel. Assume fy=415N/mm2 and fck=20N/mm2.

2. An R.C.Column 500x400mm is subjected to an axial ultimate load of 2500kN and bent in single

curvature about the minor axis with My(top)=90knm and My(bottom)=120knm as ultimate moments. If L0=7.2m and Le=5.75m on both axes, calculate the design moments for the column.

3. Design the reinforcement in a spiral column of 400mm diameter subjected to a factored load of

1500kN.The column has an supported length of 3.4m and is braced against side way. Use M20 concrete and Fe415 steel.

4. A column 300x400mm has an unsupported length of 3m and effective length of 3.6m.If it is

subjected to pu=1100kNm and Mu=230kNm about the major axis, determine the longitudinal steel using

fck=25N/mm2.

5. Calculate the ultimate strength in axial compression of column 400mm in diameter and reinforced

with 8Nos. of 20mm dia. of grade Fe250 when the column in helically reinforced by 8mm dia at (i) 60mm pitch, (ii) 30mm pitch. Assume concrete of grade M20. Assume clear cover equal to 40mm.

UNIT - V

1. A rectangular column 300mmx400mm reinforced with 20mm diameter bars carries a load of

1400kN. Design a suitable footing for the column. The safe bearing capacity of the soil is 200kN/m2.Use

concrete M20 and steel Fe415.

2. Design a combined rectangular footing for two columns spaced at 5 centers. The first column

400mmx400mm carries a load of 1200kN and the second column 450mmx450mm carries a load of

1800kn at service state. Weight of Soil = 20kN/m2, angle of repose=300 and safe bearing capacity of soil

= 150kN/m2. Use concrete M20 and steel Fe415.

3. Design a interior wall of a single storied workshop of height 5.4m surrounding a RCC roof. The

bottom of the wall rests over a foundation block. Assume roof load equal to 45kN/m. A pier provided at a spacing of 3.6m along length of wall.

4. Design a compound wall of height 1.8m to the top of 100mm thick coping. Assume wind pressure is equal to 1kN/m2 and is UDL. The safe bearing pressure of soil is 120kN/m2.

5. A solid footing has to transfer a dead load of 1000kn and an imposed load of 400kn from a square column 400mmx400mm. Assuming fck=20N/mm2 and fy=415N/mm2 and safe bearing capacity to be 200KN/m2, Design the footing.