ak temperature effect on 2 hinged arch
DESCRIPTION
ppt of subject S.A.-2 of civil engineeringTRANSCRIPT
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TEMPERATURE EFFECT Due to temperature changes , development of a horizontal
thrust in arch without loading is known as temperature effect.
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Derivation
Let α =co-efficient of thermal expansion of the arch
material
L=arch of span.
T= change of temperature in ˚C.
So Thermal expansion = αLT
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Solving for H we get
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For Circular ArchHorizontal thrust at support
Maximum bending moment= H x R.
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For Parabolic ArchHorizontal thrust at support
Maximum bending moment= H x h.
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Rib Shortening As a result of the axial thrust in the arch , the arch tends to
become deeper and hence as a consequence the horizontal
thrust tends to reduce.
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DerivationAxial thrust N=Vsinθ + Hcosθ .
Moment at any section y distance apart in y axis
Mx= M-Hy
So by castigliano’s theorem
So,
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Solving we get
has minimum value at crown.
Am= mean value of
Since
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So that
Effect of V in rib shortening is negligible.
So ,
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Combined Effect Of Temperature And
Rib Shortening Effect We get the expression
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