99. A pressure conduit laid under ground, may not be subjected to
A. internal pressure of water
B. pressure due to external load
C. longitudinal temperature stress
D. longitudinal stresses due to unbalanced pressure to bends
100. The force which develops in a pressure conduit supported on trestles, is
C. temperature stress
D. flexural stress.
101. Pick up the correct statement from the following :
A. The internal pressure within a pipe, is caused due to water head and hammer pressure
B. The internal pressure in a pipe running full is equal to vertical ordinate between hydraulic gradient line and centre of the pipe
C. In pressure pipes with water at rest, the pressure is equal to water head
D. All the above.
102. Critical time for developing a water hammer, is the
A. closing the valve
B. the wave to travel from valve to the reservoir
C. the wave to travel from the valve to the reservoir and back
D. none of these.
103. The difference in the reservoir level and the lowest point of the water mains is 180 m. The expected pressure due to water hammer is 7.5 kg/cm2 in a pressure conduit of diameter 1 m. Assuming the efficiency of the riveted joints of the pipe as 0.6 and minimum cover 3 mm for corrosion, the thickness of the pipe materials, is
A. 10 mm
B. 15 mm
C. 20 mm
D. 25 mm
104. The external load per unit length of
A. a pipe laid on, or projecting above the undisturbed ground and covered with fills, is proportional to the square of the external diameter of the pipe
B. a flexible pipe burned in narrow trenches and thoroughly compacted side fills, is proportional to the product of the width of the trench and diameter of the pipe
C. a rigid pipe burned in a narrow trenches and thoroughly compacted side fills, is proportional to the square of the width of the trench
D. all the above.
105. The maximum pressure which the pipe can withstand without any leakage during hydrostatic pressure test,- is called
A. Working pressure
B. Design pressure
C. Test pressure
D. Hydrostatic pressure.
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