L
2
L
B B
A
E E
L
DA D
CCP B
C
P
(a) (b) Beam
mechanism
(c) Frame
mechanism
(d) Combination
mechanism
(e) (f) (g)
AADDAD
B
P
E BB
E
CCCE
AD
B
E
C
1.5P
1.5P
1.5P
L
2
L
2
L
2
θL
2
θL
θL 2
2
θL
(^2) θ
θ
θ
θ θ
θ
θ θ
θ
θ
θ
2 θ^2 θ
L
2
L
2
L
2
FIGURE 2.11 Ultimate-load possibilities for a rigid frame of constant section with fixed bases.
48