Unlock document.
This document is partially blurred.
Unlock all pages and 1 million more documents.
Get Access
Problem 6.109
Compared to the truss shown in Fig. P6.109(a):
The truss in (b) subdivides members AB and BC in half.
The truss in (c) subdivides members AB,BC ,AD, and DC in half.
The truss in (d) subdivides members AB and BC into thirds.
Consider failure due to in-plane buckling only. If the truss in Fig. P6.69(a) fails
when
PD1440 lb
, specify (if possible) the values of
P
at which the trusses in
Fig. P6.69(b), (c), and (d) will fail.
Problem 6.110
The boom hangs in the vertical
x´
plane and is supported by a socket at point
N
and cables
OB
and
BP
.
The bottom flange of the boom is equipped with a roller system so that a load can be moved along its
length. Even though the top and bottom flanges of the boom are continuous members, idealize the structure
as a truss, and determine the force supported by the two cables and member
CD
when the
600 lb
load is
positioned at point C.
(6)
With
TBO DTBP D812:5 lb
, we solve this equation
Problem 6.111
A hoist for lifting building materials is attached to a scaffold. The hoist has
frictionless pulleys at points Aand B, and both pulleys have 300 mm radius.
(a) By inspection, identify the zero-force members in the truss.
(b) Determine the force supported by member DE.
(c) Determine the force supported by member EH .
Problem 6.112
If WD400 lb, determine the force supported by members BG and CF .
50.55 in./CTBG
50.25 in./D0; (4)
Problem 6.113
In the truss shown, cable segment
ML
is horizontal. If
WD6000 lb
, determine
the force supported by members
CF
,
C G
,
EG
, and
EH
.Hint: Use the method
of sections twice with cuts such as those described in Example 6.5 on p. 390.
5.4 ft/CTEG
5.3 ft/C6000 lb .3 ft/6000 lb .12 ft/D0; (5)
)TEG D5000 lb, (6)
XFyD0WTEG
Problem 6.114
Member ABCD is a single member, and points A–Hare pins.
(a) Is this structure a truss? Explain.
(b)
Is this structure statically determinate or statically indeterminate? Ex-
plain.
(c)
Determine as many reactions and the forces supported by as many mem-
bers as possible.
Problem 6.115
Member ABCD is a single member, and points A–Hare pins.
(a) Is this structure a truss? Explain.
(b)
Is this structure statically determinate or statically indeterminate? Ex-
plain.
(c)
Determine as many reactions and the forces supported by as many mem-
bers as possible.
Problem 6.116
Steps
CDE
and
F GH
are supported by a truss structure having nine members.
Determine the forces supported by all nine members of the truss.
Problem 6.117
A lifting platform is supported by members
JKF
and
LH
and hydraulic
cylinder KL. All connections are frictionless pins.
(a)
Determine the force the hydraulic cylinder must support for equilib-
rium.
(b)
Use the method of joints to determine the force supported by member
GH .
(c)
Use the method of sections to determine the force supported by
member BC .
(9)
Problem 6.118
A small trailer-mounted dumper is shown. All connections are pinned, and member
EF
is horizontal. The
hydraulic cylinder simultaneously tilts the dump and opens the gate.
(a)
Draw five FBDs, one each for hydraulic cylinder
AE
, members
BDE
and
EF
, gate
F G
, and the
dump, labeling all forces.
(b) Determine the force supported by hydraulic cylinder AE.
