A three-hinged semicircular arch of the radius R carries a uniformly distributed load of w per unit run over the whole span. Magnitude of the maximum bending moment anywhere for the arch is given by ______
1
\(\frac{{{\rm{w}}{{\rm{R}}^2}}}{2}\)
2
\(\frac{{{\rm{w}}{{\rm{R}}^2}}}{4}\)
3
\(\frac{{{\rm{w}}{{\rm{R}}^2}}}{6}\)
4
\(\frac{{{\rm{w}}{{\rm{R}}^2}}}{8}\)