Transcript Method of IC’s : Problem 1

Zero load member
Pin
Sum of all vertical
components must
be zero for
equilibrium. Hence
the vertical
component of this
force must be zero
IN ABSENCE OF
ANY EXTERNAL
FORCE ON THE
PIN. Hence the
force itself must be
zero!
Two force
members all
Finding Zero Load Members
Finding Zero Load Members
Finding Zero Load Members
Finding Zero Load Members
Finding Zero Load Members
Finding Zero Load Members
Finding Zero Load Members
Finding Zero Load Members
Method of sections
3.6 m
1500 N
1.8 m
1000 N
1.8 m
500 N
1.8 m
Determine the forces in members BC and FG of
the loaded symmetrical truss. Show that this
calculation can be accomplished by using one
section and two equations, each of which contains
only one of the two unknowns. Are the results
affected by the statistical indeterminacy of the
supports at the base
Method of sections
3.6 m
1500 N
1.8 m
1000 N
SCB
M
M
SCJ
SFJ
SFG
F
 0  3.6  SCE  1500  1.8  0  SCE  750
C
 0  3.6  SFG  1500  1.8  0  S FG  750
Method of sections
3.6 m
1500 N
1.8 m
1000 N
1.8 m
500 N
1.8 m
3.6 m
1500 N
1.8 m
1000 N
SCB
M
M
SCJ
SFJ
SFG
F
 0  3.6  SCE  1500  1.8  0  SCE  750
C
 0  3.6  SFG  1500  1.8  0  S FG  750
Curved members
Determine the force in
member AC of the loaded
truss. The two quarter
circular members act as two
force members.
Counters
Problems