A three-hinged parabolic arch rib with hinges at abutments and at crown is under the action of uniformly distributed load 'W' per unit length over its entire span 'l' through its crown. The bending moment at quarter span is

A bulldozer operates on a 30 m stretch and moves at 2.4 kmph when pushing the earth, and returns empty at 6 kmph. The time lost in loading and shifting gears per trip is 18 seconds. Its operating factor is nearly 50 min/hour. What is the number of trips made per hour ?

In the case of panel wall subjected to horizontal loads at right angles to the plane of the wall, with the mortar not leaner than M1 type, tensile stress in bending in the vertical direction may be allowed to the extent of