Determine the reactions and draw the shear and bending moment diagrams for the structures shown in Figs. P13.13–P13.25 using the method of consistent deformations.
Given beam:
Degrees of indeterminacy:
Total number of reactions of the given beam is, but we have only three equilibrium equations,
Therefore degree of indeterminacy of the beam is given by
Primary beam:
Obtained by removing the interior support B from the given indeterminate beam
Primary beam subjected to external loading
Where, denotes the deflection at B due to external loading
Therefore from virtual work method, deflection at B is obtained by
Primary beam subjected to unit value of the redundant
Where, denotes the deflection at B due to unit value of the redundant
Therefore from virtual work method, deflection at B is obtained by
Compatibility equation:
The compatibility equation can be expressed as
By substituting the values of and into the compatibility equation (1), we determine the redundantas
Therefore remaining reactions obtained by
From the equilibrium equations:
Sum of forces in X- direction is zero.
Sum of forces in Y- direction is zero.
Shear and bending moment diagrams