requires some additional equations. These additional equations come from

considering compatibility relationships $($i$.$e$.,$ continuity of displacements and

relationships between displacements and loads$).$

For an axially loaded member, the compatibility relationship for the deflections

can be written by setting the total relative axial displacement between the

ends of the member to a known value. The load$-$displacement relationship

$={\displaystyle \underset{?}{\overset{?}{}}}\frac{NL}{AE}$ gives another equation for the deflections. Once the internal

normal force of each segment is written in terms of the end reactions and

applied loads, there is enough information to solve for the reactions.

Figure