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ture 19 Cables
GR 211Fall 2007
Civil Engineering
ENGR 211 StaticsENGR 211 Statics
Yes there is recitation this week.
Im putting in all grades this week. Contact meabout missing grades after mid-week
Final Thurs Dec. 6th @ 7:30 am Milam 28
Dear118
Alternate Final: send me an email
Wednesday: Review of Class
What I think was important
(Thats what will be on the Final)
Answer as many Qs as possible
Final Exam Closed book, closed
notes
BUT.
You may bring one8- x 11 (max) sheet
with both sidescrammed withwhatever.
Civil Engineering
CablesCables (from Chapter 7 and(from Chapter 7 andAdditional Material on pg. 414FAdditional Material on pg. 414F--K)K)
Analysis
based ontype ofload
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ture 19 Cables
GR 211Fall 2007
Civil Engineering
Loads Distributed UniformlyLoads Distributed Uniformly
Along a Straight LineAlong a Straight Line
0
wa
T=
21
2 y ax=
Civil Engineering
Loads Distributed Uniformly Along a Straight LineLoads Distributed Uniformly Along a Straight Line
0
wa
T=
2 20
1T T a x= +
2 2 2 21 11 ln 12
s x a x ax a xa
= + + + +
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ture 19 Cables
GR 211Fall 2007
Civil Engineering
Golden Gate Bridge
21
2 y ax=
So, a = 2.83 x 10-4 ft-1
Civil Engineering
0
wa
T=
Assume w= 22 kips/ft. (each side)
2.83 x 10-4 =
2 20
1T T a x= +
y = (1.19 x 10-4)x2 m
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4/12
ture 19 Cables
GR 211Fall 2007
Civil Engineering
0
wa
T=
Assume w= 22 kips/ft. (each side)
2.83 x 10-4 =
2 20
1T T a x= +
y = (1.19 x 10-4)x2 m
Civil Engineering
Assume w= 22 kips/ft. (each side)
y = (1.19 x 10-4)x2 m
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5/12
ture 19 Cables
GR 211Fall 2007
Civil Engineering
Dead Load 41 kips/ft
Live Load 4000 lb/ftCost (1937) $35 million
Today (est.) $1.2 billion
Civil Engineering
11 men died
Safety innovations hard hats and safetynet
19 in Halfway-to-HellClub
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6/12
ture 19 Cables
GR 211Fall 2007
Civil Engineering
Catenary Cables
Civil Engineering
Load Uniformly Distributed Along a CableLoad Uniformly Distributed Along a Cable
Catenary Curve
0
wa
T=
( )
1
cosh 1 y axa=
0coshT T ax=
sinh axs
a=
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7/12
ture 19 Cables
GR 211Fall 2007
Civil Engineering
Find the Sag & Tmax
T0 = 1.8kN
Cable has mass 2 kg/m
0
w
a T=
Civil Engineering
0
wa
T=
( )
1cosh 1 y ax
a=
= 0.0109
0coshT T ax=
sinh axs
a=
8/2/2019 19.6 Cables
8/12
ture 19 Cables
GR 211Fall 2007
Civil Engineering
Power Lines
ACSR AluminumConductor SteelReinforced
#6 (Code Name Turkey)
0.198 diameter
6 AL x 1 GalvanizedSteel
24.5#/1000 AL
11.6#/1000 Steel
36.1#/1000 Total
Guys
dia. Galvanized SteelWire Rope
Earth Anchors
Civil Engineering
Power Line ExampleTypical Rural Lines
Approx. 300 Spacing
20 Ground Clearance
Sag = 5
Find T0 and length andangle
8/2/2019 19.6 Cables
9/12
ture 19 Cables
GR 211Fall 2007
Civil Engineering
Power Line Example
Typical Rural Lines
Approx. 300 Spacing
20 Ground Clearance
Sag = 5
Find T0 and length and angle
( )
1cosh 1 y ax
a
=
sinh axs
a=
0
wa
T=
Graphical Solution for a cable
y=1/a*(cosh ax -1) for x = 150 ft.
0.00
2.00
4.00
6.00
8.00
10.00
12.00
0 0.00005
0.0001
0.00015
0.0002
0.00025
0.0003
0.00035
0.0004
0.00045
0.0005
0.00055
0.0006
0.00065
0.0007
0.00075
0.0008
0.00085
0.0009
a, ft-1
y,
ft.
Civil Engineering
Power Line ExampleTypical Rural Lines
Approx. 300 Spacing
20 Ground Clearance
Sag = 5
Find T0 and length and angle
( )
1cosh 1 y ax
a=
sinh axs
a=
0
wa
T=
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10/12
ture 19 Cables
GR 211Fall 2007
Civil Engineering
150
1cosh 1
ft
d axdy a
dx dx
=
cosh sinhd
d dxdx
=u
u u
150 150sinh
ft ft dy axdx
=
Find the angletangent to thecable @connection point
Civil Engineering
Find the angletangent to thecable @connectionpoint
( )
1cosh 1 y ax
a=
( )
1cosh 1 y ax
a= @ 140=4.41 ft.
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ture 19 Cables
GR 211Fall 2007
Civil Engineering
Oakland Skyway BridgeOakland Skyway Bridge Most expensive construction project
in California history
Civil Engineering
OSU Grads in chargeOSU Grads in charge
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ture 19 Cables
Civil Engineering
Tacoma Narrows BridgeTacoma Narrows Bridge
19401940
Civil Engineering
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