Subject 2014 Question Paper — Government College of Engineering and T…

Instructions

• Attempt four questions in all selecting at least two questions from each Section.
• Assume missing data suitably, if any.
• Use of IS 456, IS 800 and steel table is allowed.

Questions

Section A

• Q1. Design a R.C. slab for a room measuring 5 m x 6 m size. The slab is simply supported on all the four edges with corners held down and carries a superimposed load of 3000 N/m² inclusive of floor finishes etc. Use M20 mix and Fe 415 steel. [38 marks]
• Q2. Design a dog-legged stair for a building in which the vertical distance between floors is 3.6 m. The stair hall measures 2.5 m x 5 m. The live load may be taken as 2500 N/m². Use M20 and Fe 415 steel. [38 marks]
• Q3. Design a cantilever type retaining wall to retain sand for 3.75 m above the ground level. The sand fill slopes at the rate of 1 vertical to 2 horizontal. The weight of the sand is 18000 N/m³ . The safe bearing capacity of the soil is 200 KN/m² at a depth of 1.25 m below the general ground level. The angle of repose of the soil is 30° use M20 and Fe 415. Take coefficient of friction = 0.6 [38 marks]
• Q4. a What is anchorage slip? How do you compute the loss of stress due to anchorage slip? b Differentiate between full prestressing and partial prestressing. c A prestressed concrete beam 250 mm wide and 360 mm deep has a span of 12 m. The beam is prestressed by steel wires of area 350 mm² provided at a uniformly eccentricity of 60 mm with an initial prestress of 1250 N/mm². Determine the percentage loss of stress in the wires if the beam is a pretensioned beam and post tensioned beam. Take Es = 210 KN/mm², Ec = 35 KN/mm². Ultimate creep strain = 45 X 10⁻⁶ mm/mm per N/mm² for pretensioned beam and 22 X 10⁻⁶ mm/mm per N/mm² for post tensioned beam. Shrinkage of concrete = 300 x 10⁻⁶ for pretensioned beam and 215 X10⁻⁶ for post tensioned beam. Relaxation of steel stress = 5% of the initial stress, Anchorage slip = 1.25 mm, Friction coefficient for wave effect K = 0.00015 per m.

Section B

• Q5. a Explain in brief the various types of rivet failure with neat sketches b A tension member 10 m long is subjected to an axial tensile load of 1200 KN. Design the section with channels facing each other. The rolled section available is I.S.M.C 300 @ 351.2 N/m only. The channel sections are weakened by one rivet hole on each flange. Check the adequacy of the section and provide the plates if required.
• Q6. Design a built up column 10 m long to carry an axial load of 750000 N. The column is restrained in position but not in direction at both the ends. Provide single lacing system with riveted connections. Assume fy = 250 MPa. i) Design the column with two channel placed back to back ii) Design the column with two channels placed toe to toe iii) Design the lacing system with welded connections for channels back to back. [37 marks]
• Q7. Design a grillage foundation for a compound column consisting of ISHB 400 @ 82.2 kg/m with flange plates 350 x 20 mm one on each flange and carrying a load of 3000 KN. The base plate has size 800 mm x 900 mm. The grillage is supported on soil of bearing capacity of 200 KN/m² [37 marks]