Advanced Methods of Structural Analysis

12.5 Limit Plastic Analysis of Frames 443

P

Q= 2 P

l/2

l

h=l

/2

A B

CD

K

a

Qlim

a

vert l/2

My Mvert

y

Mhory

a

Q

b

P

b h

Plim

b b

c

Mverty

Mvert

y

Mvert

y

Mvert

y

Plim

q h Qlim

q

l/2

q

q Q

P

d

q

Mvert

y

Mvert

y

Mvert

y

Mhory

0481612

0

4

12

8

16

Qliml

B

S

B+S

5.33

10.66

e

Mvert

v

Pliml

Mvert

y

Fig. 12.10(a) Design diagram of a portal frame; (b) Beam mechanisms of failure (B);
(c) Sidesway mechanisms of failure (S); (d) Combined mechanisms of failure.BCS/;(e)Graph
of limit combination of loads