Question

Hence, SFD and BMD are as
Erample 5.8 A girder 6 m long rests on two supports with equal overhangs on either side and
camies a uniformly distributed load of 30 kN per metre run over the entire length. Calculate the
overhangs if the maximum bending moment, positive or negative, is to be as small as possible. Draw
SFD and BMD diagrams for the double overhang beam.
Solution​

Answer 1

Answer:

Explanation:

Step 1

Draw a free body diagram converting the UDL into a point load

As UDL is given 5kn and it is acting on the 2m length

Therefore, load will be 5 x 2 = 10 kN acting on center of 1m from point B.

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Step 2

Take moments @A, we know the condition

Anticlockwise moment = clockwise moments

We know moment = force x perpendicular distance

RB x 5 = (10 x 1) + (10 x 4)

RB x 5 = 50

RB = 50/5= 10 kN.

 

Summation of upward force = summation of downward force

RA + RB = 10+10

RA + 10 = 20

RA = 20 – 10

RA = 10 kN

Step 3

Shear force calculations:

Shear force is the algebraic sum of unbalanced vertical forces to left or right of the section.

So, if we start calculating from left side then upward force will be positive and downward force will be negative and if we start calculating from the right side of t...