STUPIDSID
Answer any one question from Q.1 and Q.2
1(a)
What are bonded and unbonded prestressed concrete members?
4 M
Answer any one question from Q.1 and Q.2
1(a)
Explain stress, force and load balancing concept in prestressed concrete.
3 M
1(b)
Calculate the loss of pre-stress due to elastic shortening of concerete in a simple supported pre-tensioned beam of effective span 20m. The cross-section of the beam is an I-section on having the top and bottom flanges as (700 × 200) mm and the web of width 150 mm. The overall depth of the beam is 1,200 mm. The prestressing cable of cross-sectional area of 2,100 mm2 is provided at 100mm from the bottom. The initial pre-stress in steel may be taken as 1,360 N/mm2. The stress in concrete at transfer is 30 N/mm2
6 M
1(b)
A pre-tensioned concrete beam has a cross section 250 mm × 360 mm prestressed by a cable having a cross sectional area of 502 mm2. The centroid of the cable is located at 105 mm from the soffit. Find the percentage loss of stree in steel to creep, shrinkage, elastic shortening of concrete and 5% relaxation of stress in steel. The initial prestress in steel is 1000 Mpa.
Take Es=210 Gpa, Ec=36.8 Gpa and creep coefficient=1.6.
Take Es=210 Gpa, Ec=36.8 Gpa and creep coefficient=1.6.
7 M
2(a)
What are Type -I, -II and -III prestressed concrete members?
4 M
2(a)
Why high strength steel is used in prestressed concrete. Explain with suitable example.
3 M
2(b)
An end block of a post tensioned beam is 350 mm × 500 mm. The prestressing force is 900 kN with the tendon placed centrally at the ends. A bearing plate of 200 mm × 200 mm is provided. Check for the bearing stresses developed in concrete whose strength at transfer is 40 N/mm2
6 M
2(b)
A prestressed concrete beam of 6 m span rectangular in cross section 400 mm × 600 mm is prestressed with a tendon having parabolic profile with an eccentricity of 100 mm at mid span and zero at supports. The tendon carries a prestressing force of 1000 kN. If the total external load on the beam (excluding its self - weight) is 15 kN/m, calculate the stresses in the extreme fibers at mid-span and at support sections.
7 M
Answer any one question from Q.3 and Q.4
3
Design two way slab of size 7.5m × 10m supported on four beams and discontinuous over one long edge. The slab supports alive load 5kN/m22. The breaking load of the stand may be taken as 44.48 kN. The loss coefficient is 0.85.
10 M
Answer any one question from Q.3 and Q.4
3(a)
Explain the necessity of designing anchorage zone in post tensioned beam with reference to stress trajectories. How the design of end block will be carried out.
4 M
3(b)
For an unbraced building having plan dimensions 30 m × 30 m, the total seismic load on a frame having 5 similar bays is 14800 kN. The building is situated in zone III. Footing is resting on medium soil. The total height of the building is 28 m with floor height as 4 m. Calculate the base shear and show shear distribution over the height of the building.
6 M
4
The cross section of a prestressed concrete beam is an unsymmetrical T section with the following dimensions : overall depth ' 1200 mm, web -200 mm and flange ' (1000 × 200)mm. At a particular section the beam is subjected to ultimate moment and shear force of 2000 kNm and 250 kN respectively. Design the beam for shear with the following data : grade of concrete ' M40, effective depth ' 1100 mm, Ap=2310 mm2, fp=1500 Mpa, η=0.6, effective prestress at extreme tensile face of the beam=19.30 Mpa.
10 M
4(a)
Explain the Indian standard code provisions for calculating the moment of resistance for rectangular beams.
4 M
4(b)
A building consists of three frames comparising of three storey with two equal bays of 4 m width. The frames are placed 5m c/c. The lateral panel point loads of a frame are 18 kN at teracce floor and 24 kN at typical floor. Find the moments and shears in all beams for the internal frame by suitable method.
6 M
Answer any one question from Q.5 and Q.6
5
The plan and elevation of a three storey RC school building located in Pune is shown in Fig. 5. The building consists of OMRF and rests on hard soil. The sizes of structural components and loads are as follows : slab ' 150 mm, beam-(230 × 450)mm, columns-(230 × 500)mm, live load on floors ' 4.0 kN/m2, live on roof ' 1.5 kN/m2, floor finish ' 1.0 kN/m2, water proofing load ' 2.0 kN/m2. Analyze the frame using seismic coefficient method.
:!mage
:!mage
10 M
Answer any one question from Q.5 and Q.6
5(a)
For a T-shaped retaining wall draw the active earth pressure diagram showing the expression for maximum earth pressure for the following conditions.
i) backfill is a completely submerged soil with top surface horizontal, and
ii) Backfill is horizontal with uniform surcharge ws/unit run.
i) backfill is a completely submerged soil with top surface horizontal, and
ii) Backfill is horizontal with uniform surcharge ws/unit run.
4 M
5(b)
Perform stability analysis for a T-shaped retaining wall provided to retain a horizontal leveled backfill which consists of two layers of 2 m each. The upper layer and bottom layer has unit weight respectively equal to 17 kN/m3 and 18 kN/m3 Angle of repose for both layers = 30°, coefficient of friction between Concrete and soil = 0.55, SBC of soil = 150 kN/m2, depth of foundation = 1.0 m.
12 M
6
Design a L-shaped retaining wall to retain a backfill of 3.2 m. The backfill is horizontal; and is subjected to a surcharge of 10 kN/m2 acting over a length of 2m starting from 1m from the face of the wall. The unit weight of the soil is 17 kN/m3, angle of repose = 30°, SBC of soil = 180 kN/m2, good foundation is available at a depth of 1.0 m. Sketch the details of reinforcement in the wall and base slab.
16 M
6
For the frame given in Q.5, analyze the first floor beam using appropriate substitute frames for obtaining maximum span and support moments. Sketch the bending moment diagrams.
:!mage
:!mage
10 M
Answer any one question from Q.7 and Q.8
7(a)
Why it is necessary to combine the footing?
3 M
7(b)
Design a slab-beam type combined footing for two boundary columns spaced 4.0 m apart. The columns are 230 mm × 400 mm. Both columns carry 600 kN characteristics loads. The SBC of soil is 200 kN/m2. Use M30 grade of concrete and steel of grade Fe 500.
13 M
8
Design a slab type combined footing for two columns spaced 3.5 m apart carrying a service load of 600 kN and 1000 kN each. The columns are 400 mm × 400 mm and 600 mm × 600 mm respectively. The center of lighter column is 0.4 m from the property line. The SBC of soil is 180 kN/m2. The width of the slab shall be taken as 2.0 m. Use M30 grade of concrete and steel of grade Fe 500.
16 M
ANswer any one question from Q.9 and Q.10
9(a)
A rectangular water tank 5 m × 2.5 m × 2.5 m high is resting on ground. The tank wall is free at top and hinged at bottom. Determine the maximum bending moments at mid - span and support as per IS 3370 in the long wall and short wall.
6 M
9(b)
Using limit state method, design the section of a circular water tank with flexible base and resting on ground. The wall is subjected to a maximum hoop tension of 240 kN. Use Fe 500 grade of steel and M35 grade of concrete. The limiting design surface crack width may be taken as 0.1mm.
12 M
10
Design the long wall for a rectangular water tank open at top resting on ground having a size of 8.0 m × 3.6 × 2.5 m high. Use M 30 and Fe 500 grade material. Sketch details of reinforcement for the wall.
18 M
More question papers from Structural Design & Drawing- III