Arches
Learning Objectives
• You will be able to describe an arch
• You will be able to describe the uses of arches
• You will be able to differentiate between determinate and indeterminate arches
• You will be able to analyze determinate arches
Arches
Arch is a structure primarily in Compression
Clear Span
Effective Span
Voussiour
Abutment Abutment
KeystoneExtrados(externalcurve)
Intrados(internalcurve)
Soffit(bottom susrface)
Uses
• buildings
•bridges
Materials
• stone
•brick
•concrete
•steel
Is this ok?
What is the problem with this Arch?
Indeterminate
B
0=Σ BM
A B
Two unkowns Two unknowns
Arches
Three-hinged Arch - Determinate
Two -hinged Arch - Indeterminate – order one
Fixed Arch - Indeterminate – order three
B
0=Σ BM
000
=Σ=Σ=Σ
y
x
i
FFMA C
P= 1198 kP= 1198 k
B
154 ft
AC
l/4l/4
188.5 ft188.5 ft
l
PTwo Hinged Arch
P
Three Hinged Arch
Determinate and Indeterminate Arches
Three Hinged Arch-
Determinate
Two Hinged Arch-
Indeterminate ,1st order
Fixed Arch-
Indeterminate,3rd order