B4B051 Pages: 3

7. a) Justify that an arch is more economical compared to a SS beam of same span carrying
the same load. (6)

0) A 3 hinged parabolic arch has a horizontal span of 36m with a central rise of 5m. A
udl of 1kN/m acts at right half of the span. Calculate the magnitude and position of
maximum positive BM in the arch. Also calculate the BM, NT and RS at left quarter
point. (14)

8. a) A bridge cable is suspended from towers 80 m apart and carries a load of 30 kKN/m
on the entire span. If the maximum sag is 8 m, calculate the maximum tension in the
cable. If the cable is supported by saddles which are stayed by wires inclined at 30° to
the horizontal, determine the forces acting on the towers. If the same inclination of back
stay passes over pulley, determine the forces on the towers. Height of the tower
is 10m. (14)

b) Illustrate Eddy’s theorem in arches. (6)
9. a) A3 hinged semi-circular arch ACB of uniform section and radius ‘r’ carries a udl of

w/m run over the whole span. Find the position and magnitude of maximum

bending moment. Draw the BMD. (14)
b) For a cable carrying concentrated loads, estimate the maximum and minimum
tensions and their locations. (6)

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