A simply supported beam of span length 4m, carries a concentrated load of 8 kN at mid span, the value of maximum bending moment is:

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NPCIL Stipendiary Trainee ME 2018

Answer 1

Concept:

A simply supported beam with span L and centered load P is,

SSC JE ME 25 Jan 18 Evening Uploading.docx Shraddha 10

RA + RB = P ---(1)

∑MB = 0

\({R_A} \times L - P \times \frac{L}{2} = 0\)

\({R_A} = \frac{P}{2}\)

\({R_B} = \frac{P}{2}\)

The BM will be maximum on the point at which shear force changes its sign.

So the value of bending moment at a distance x = L/2 is:

\({M_{\frac{L}{2}}} = {R_A}\frac{L}{2} = \frac{{PL}}{4}\)

SSC JE ME Strength of Material Part test (1-35) images Q2

Calculation:

Given:

P = 8 kN, L = 4 m

Maximum bending moment, \({M} = \frac{PL}{4}\)

\({M} = \frac{8\times 4}{4}=8~kN.m\)