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