Question

A circular three-pinned arch of span 40 m and a rise of 8m is hinged at the crown and springings. It carries a horizontal load of 100 kN per vertical metre on the left side. The horizontal thrust at the right springing will be

• A. 800 kN
• B. 600 kN
• C. 200 kN
• D. 400 kN

Answer 1

The correct option is C 200 kN


The vertical reaction at B is

$V_B\times 40=100\times 8\times 4$
$V_B=80kN$
For horizontal thrust at B taking moment of right part about crown (C)

$V_B\times 20=H\times 8$
$\therefore H=\frac{80\times 20}{8}=200kN$