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  • 8/2/2019 19.6 Cables

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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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    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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    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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    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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    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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    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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    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=

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    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

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    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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    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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    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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    Civil Engineering

    Tacoma Narrows BridgeTacoma Narrows Bridge

    19401940

    Civil Engineering

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