Load Tracing 1Lecture 10

Architectural Structures IENDS 231

S2008abn

ARCHITECTURAL STRUCTURES I:STATICS AND STRENGTH OF MATERIALS ENDS 231

DR. ANNE NICHOLS

SPRING 2008

ten

load tracingand types

lecture

Load Tracing 2Lecture 10

Architectural Structures IENDS 231

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Structural Loads• gravity acts on mass (F=m*g)• force of mass

– acts at a point• ie. joist on beam

– acts along a “line”• ie. floor on a beam

– acts over an area• ie. people, books,

snow on roof or floor

Load Tracing 3Lecture 10

Architectural Structures IENDS 231

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Load Tracing• how loads are

transferred– usually starts at top– distributed by

supports as actions– distributed by

tributary areas

Load Tracing 4Lecture 10

Architectural Structures IENDS 231

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Load Tracing

tributary area

Load Tracing 5Lecture 10

Architectural Structures IENDS 231

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Load Tracing• tributary load

– think of water flow– “concentrates” load of

area into center

( )widthtributaryarealoadw ×⎟

⎠⎞

⎜⎝⎛=

width

Load Tracing 6Lecture 10

Architectural Structures IENDS 231

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Load TracingPatcenterRogers 1986

Load Tracing 7Lecture 10

Architectural Structures IENDS 231

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Load TracingAlamillo BridgeCalatrava 1992

Load Tracing 8Lecture 10

Architectural Structures IENDS 231

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Load Paths

Load Tracing 9Lecture 10

Architectural Structures IENDS 231

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Load Paths• wall systems

Load Tracing 10Lecture 10

Architectural Structures IENDS 231

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Load Paths• openings & pilasters

Load Tracing 11Lecture 10

Architectural Structures IENDS 231

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Load Paths• foundations

Load Tracing 12Lecture 10

Architectural Structures IENDS 231

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Load Paths• deep foundations

Load Tracing 13Lecture 10

Architectural Structures IENDS 231

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Concentrated Loads

Load Tracing 14Lecture 10

Architectural Structures IENDS 231

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Distributed Loads

Load Tracing 15Lecture 10

Architectural Structures IENDS 231

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Distributed Loads• statically determinate beam supports

– simple

– overhang

– cantilever

L

L

L

Load Tracing 16Lecture 10

Architectural Structures IENDS 231

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Distributed Loads• continuous beams

– statically indeterminate– floors

L L

Load Tracing 17Lecture 10

Architectural Structures IENDS 231

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Equivalent Force Systems• replace forces by resultant• place resultant where M = 0• using calculus and area centroids

dx

w(x)

x

L

loadingloading

L

0AdAwdxW === ∫∫

dx

y

x

elx

Load Tracing 18Lecture 10

Architectural Structures IENDS 231

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Area Centroids• Table 7.1 – pg. 242

b

h3b

right triangle only

Load Tracing 19Lecture 10

Architectural Structures IENDS 231

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Load Areas• area is width x “height” of load• w is load per unit length• W is total load

x

x/2

W

x/2

x

2x/3

W/2

x/3

x

x/2

W

x/6 x/3

W/2

0

Wxw =⋅ w w 22Wxw

=⋅

w 2w