Section A
Q1.
(a) A car as shown in the figure below is being towed at a steady speed up on an inclined plane having an angle of 15° with the horizontal. The car weighs 1635 kg. Show the free body diagram of the car and calculate the supporting force on each wheel and force T. (b) A steam engine piston of length 80 cm is subjected to a maximum load of 60 kN. If the ends are fixed and the length factor is 0.6, determine the diameter of the piston by using Rankine's formula. Take yield stress as 100 MPa and Rankine's constant as
7500 (c) A simply supported beam of T-section (flange = 100 mm × 20 mm and Web = 150 mm × 10 mm) is 2.5 m in length. It carries a load of 3.2 kN inclined at 20° to the vertical and passing through the centroid of the section. Determine the maximum tensile stress induced in the section. (d) What is non-conventional prestressing ? Discuss two important non-conventional prestressing methods. (e) A rectangular prestressed beam of cross-section 175 mm × 350 mm has an effective span of 12 m. The beam is prestressed by using a cable with zero eccentricity at the supports and linearly varying to 75 mm at the centre. The cable carries a prestressing force of 600 kN. Find the magnitude of the concentrated load located at the centre of the span for the following conditions at a section at the centre of the span:
(i) if the load counteracts the bending effect of prestressing force. Neglect the self-weight of the beam.
(ii) if the pressure line passes through the upper kern of the section under the action of the external load, self-weight and prestress.
