Q.1 The figure shows a two-hinged parabolic arch span L subjected to a uniformly distributed load of intensity q per unit length.
The maximum bending moment in the arch is equal to [2017 : 1 Mark, Set-I]
If a two hinged or three hinged parabolic arch is subjected to UDL throughout its length, bending moment is zero everywhere.
Q.2 A three hinged parabolic arch having a span of 20 m and a rise of 5 m carries a point load of 10 kN at quarter span from the left end as shown in the figure. The resultant reaction at the left support and its inclination with the horizontal are respectively [2010 : 2 Marks]
(a) 9.01 kN and 56.310
(b) 9.01 kN and 33.690
(c) 7.50 kN and 56.310
(d) 2.50 kN and 33.690
Let the vertical reactions at left and right support be VL and VR upwards respectively.
Taking moments about right support, we get,
Let the horizontal reaction at left support be Hfrom left to right.
Taking moments about the crown from left, we get,
⇒ H = 5kN
Let the resultant reaction at the left support makes an angle θ with the horizontal.