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Code No: NR320102

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III B.Tech II Semester Supplimentary Examinations, Apr/May 2009 STRUCTURAL ENGINEERING-III (RCC AND STEEL) DESIGN AND DRAWING (Civil Engineering) Time: 3 hours Max Marks: 80 Answer any ONE Question from PART-A and any THREE Questions from PART-B Note:Assume suitable data whenever necessary Use of IS codes & Structural Tables is permitted ????? PART-A(Marks:32)

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1. The following data pertains to a deck slab bridge Clear span: 5.5 m Width the footpath:1 m on either side. Wearing coat : 100 mm Loading : IRC class AA (Tracked) Materials : M25 concrete and Fe 415 steel Design the deck slab. Draw the following to a suitable scale.

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(a) Longitudinal Section showing top and bottom reinforcements (b) Cross-section showing details of reinforcement in slab and kerb portion.[24+8]

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2. Data pertaining to a through type plate girder railway bridge for single track Broad Gauge (B.G) main line loading is given below. Effective span = 24 m Spacing of main girders = 5 m center to center Spacing of cross beams = 3 m center to center Spacing of stringers = 2 m center to center Weight of stock rails = 450 N/m Weight of guard rails = 250 N/m Weight of fastenings = 280 N/m of track Timber sleepers = 250 mm X 150 mm X 2.8 m @ 0.4 m center to center Density of Timber = 7.4kN/m3 Design the following for the above data. (a) Stringers and cross-beams

(b) Mid-span section of the Plate Girder

Take permissible stresses in accordance with railway steel bridge code provisions. Stiffeners and bracings need not be designed. Draw to a suitable scale, the following (a) Plate girder section at mid-span (b) Part elevation 1 of 2

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Code No: NR320102 (c) Assuming suitable section for bracings, draw top plan.

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PART-B (Marks:16x3=48)

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3. A solid slab bridge has a clear span of 5.75 m and a clear width of road way as 7.8 m. It has to carry IRC Class A loading. Design a suitable kerb for this bridge using M20 concrete and Fe 415 grade steel. The kerb may be designed for a live load of 4.5 kN/m2 and for a lateral load of 7.0 kN/m length. [16] 4. Write short notes on the following.

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(a) Courbon’s method (b) Pigeaud?s curves.

[16]

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5. A foot bridge of effective span 18 m has a clear width of 2.5 m. the flooring consists of timber planks. Use a Warren-type truss with 6 panels of 3 m each. Cross girders are provided at 3 m spacing. The live load may be assumed as 4000N/m2 . Design the cross girders and central panel members. [16]

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6. A suitable stair has to be located in a staircase 6.1 m long and 3.66 m wide and 3.66 m high with a door 1.075 m wide in each of the longitudinal walls. The doors face each other and are located with their centers at a distance of 1.0 m from the respective corners of the staircase. Assuming that it is a public building, design the stair and draw a dimensional plan adopting a open well type stair. Use M20 grade of concrete and HYSD steel bars with an allowable stress of 230 MPa. Assume the unit weight of concrete = 23kN/m3 . [16]

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7. The capacity of an Intze type water tank is 650,000 litres. The height of the staging is 17.5 m up to the bottom of tank. Assume the intensity of wind pressure as 1550N/m2 . Work out suitable dimensions for the tank. Design the top dome and bottom ring beam. Use M20 concrete and mild steel bars with an allowable stress of 140 MPa. [16]

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