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Design of Bridges Part A (5 x 2 =10)

1. Why movements are induced in superstructure? (L)2. Mention five types of expansion bearings. (L)3. State the forces acting on bridges. (R)4. Draw a neat sketch of anchor foundation. (R)5. What are the factors on which foundation design depend upon? (L)

Part B (8 + 16 +16 = 40)6. A) i) Draw a neat sketch of Plate girder showing ITS and LS (R)

ii) State the difference between open caisson and pneumatic caisson. (R)iii)Explain sliding plate bearing with neat sketch (U) iv)How will you compute the rotation at the supports? (A)

(Or)B)Enumerate different types of deep foundations (any 4) with sketches. (R)

7. (A) Design an elastomeric pad bearing to support Tee beam girder of a major bridge using the following data:

(C)Maximum dead load reaction per bearing = 330 KNMaximum Live load reaction per bearing = 500 KNLongitudinal force due to friction for each bearing = 30 KNEffective span of girder = 20mEstimated rotation at the bearing of the girder due to dead and live loads = 0.004 radians. Concrete used for Tee beam and bed block = M20 concrete.Shear strain due to creep, shrinkage and temperature = 5 x 10-4. Sketch the details of bearing also

(Or)

B) A well foundation is to be designed for an abutment of 10m x 5m base dimensions. The well is founded on a sandy soil. The data available are as follows: (C)

Height of bearing above maximum scour level : 28 m ; Permissible horizontal displacement of the bearing level : 50m

Height of abutment : 6m

Total vertical load including weight of abutment and well: 20,000 KN

Total lateral load At the scour level = 400 KN

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Submerged unit weight of soil : 9.5 KN/Cu.m

Design the well and verify the stresses in the steining.

8. A) Explain a) Steel Rocker Bearing b) R.C. Hinge (Rocker ) Bearing. (R)(Or)

B)Explain different types of piers and abutments with neat sketches (R)

1. How will you select the type of bridges? (E)2. Why do you calculate impact effect on bridges? (L)3. What do you mean by effective width of dispersion? (R)4. When will you adopt Courbon’s method (U)5. When do you prefer Tee Beam and slab bridges? (L)

Part B (8 + 16 + 16)6 A) (1) Write down the advantages of continuous bridges . (R)

(2) Draw a neat sketch of Box girder and mention its parts. (U)

(3) Why do you provide articulation? (L)

(4) What are the different types of well foundation? (R)

(Or)

(B) Explain with sketches the three types of Caisson foundation. (A)

7 A) Discuss the design principles of balanced cantilever bridges (R)(Or)

B) Discuss the design principles of continuous bridges. (R)

8 A) Obtain Courbon’s reaction factor and the maximum bending moment in case of T – beam bridge having the following details: (L)

Roadway: 2 lanes

Loading : IRC Class A; Number of main girders : 3 ; c/c spacing 2.6m; span of the bridge: 16m ; Foot path : 1m on either side.

(Or)

(B) Design the reinforcement and show the details of reinforcement for articulation when D = 120cm, a= 40cm, B = 75 cm, where “D” is the depth of articulation, “a” is the distance of

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vertical reaction from articulation and “B” is the width of articulation. Vertical and Horizontal loads are 1000 KN and 200 KN respectively. (L)