For a fixed beam with a concentrated load w at \(\frac{1}{4}\) of

For a fixed beam with a concentrated load w at \(\frac{1}{4}\) of
| For a fixed beam with a concentrated load w at \(\frac{1}{4}\) of span from one end, the ultimate load is 

A. <span class="math-tex">\(\frac{{16{M_p}}}{{3L}}\)</span>

B. <span class="math-tex">\(\frac{{4{M_p}}}{L}\)</span>

C. <span class="math-tex">\(\frac{{32{M_p}}}{{3L}}\)</span>

D. <span class="math-tex">\(\frac{{6{M_p}}}{L}\)</span>

Please scroll down to see the correct answer and solution guide.

Right Answer is: C

SOLUTION

Given:

Fixed beam with concentrated load L/4 from one end

Calculation:

Number of Plastic hinges = Ds + 1 = (4 - 2) + 1 = 3

i.e. at A, B and C

From geometry,

\(\Delta = \frac{L}{4}{\theta _A}\) and \({\theta _A} = 3{\theta _B}\)

According to virtual work principle,

External work done = Internal work Done

\(W\Delta = {M_P}{\theta _A} + {M_P}{\theta _A} + {M_P}{\theta _B} + {M_P}{\theta _B}\)

\(W\frac{L}{4}{\theta _A} = 2{M_P}{\theta _A} + \frac{{2{M_P}{\theta _A}}}{3}\)

\(\Rightarrow W = \frac{{32}}{3}\frac{{{M_P}}}{L}\)