Advanced Methods of Structural Analysis

3.3 Simple Trusses 51

RA

1

2

4

(^35) U^7
5–7
D4–7
O4–6
r
r 1
1
1
RB
1
4
6
7
8
10
9 11
12
O4–6
U5–7
D4–7
r
r 1
1
1
r 1 =5.972m
r=3.655m
a
O4–6
6
V6–7
O6–8
22 j
3
V2–3
U3–1 U3–5
4 4
O1–2
RA
1
U1–3
3
3
b j
c
Inf. line V6–7
23 d^23 rdsin j=^2
rsin j +
1
h=4m,
d=3m
r 1 =5.972m
r=3.655m
sinj= 0.4061
RA RB
d
1
2
4
6
7
8
10
3911
P= 1
5
12
r h
r 1
j
Inf. line D4–7
6 d
r 1 =3.014
Left-hand portion
Right-hand portion
Connecting line
−
1.004
Inf. line U1–3
3 d 2.25
h=
Right-hand portion

• 1.875
  Connecting line
  Inf. line U5–7
  6 d
  3 d h=4.5
  h
  Connecting line
  Left-hand portion + Right-hand portion
  1.5
  1
  Inf. line V2–3


• 
  

  1
  Inf. line RA

  
  


• 
  

  Inf. line O4–6
  3 d
  r=2.462
  3 d
  r
  Left-hand portion Right-hand portion
  Connecting line
  −
  1.231
  Fig. 3.14 (a) Free-body diagrams for left and right parts of the truss. (b) Free-body diagrams for
  specified joints of the truss. (c) Influence lines for truss with lower loaded chord