2. Principle of Superposition
P2P1
l 2 l 2
A, E
Δl = Δl1 Δl2+
P1
l 2
Δl1 P2
l
Δl2
For linear elastic structures, the load effects caused by multiple loads
are the sum of the load effects caused by each load.
3. Solving Statically Independent Beam
by Principle of Superposition
l1 l2
P
A, E
a b c
l = l1 + l2
x
RcRa
P
l1
Rc
AE
Pl1
ΔlP=
AE
Rcl
Δl =Rc
ΔlP ΔlRc
=+ 0
Rc
l1 l2+
l1
= P−
Geometric condition
Ra RcP =+ + 0
Ra=−
l1 l2+
l2
P
Equilibrium of force
4. Summary
1. Understanding of Superposition
2. Employing Principle of Superposition
= +
For linear elastic structures, the load effects caused by multiple loads
are the sum of the load effects caused by each load.