What is an Arch? An arch is a structure that spans a space and supports structure and weight above it. Arches appeared as early as the 2nd millennium BC in Mesopotamian brick architecture and their systematic use started with the Ancient Romans who were the first to apply the technique to a wide range of structures. What are the Types of Arches? Arches have many forms, but all fall into three basic categories: Circular, pointed, and parabolic. Arches with a circular form, also referred to as rounded arch, were commonly employed by the builders of ancient history, heavy masonry arches. Ancient Roman builders relied heavily on the rounded arch to span large, open areas. Several rounded arches placed in-line, end-to-end, form an arcade, such as the Roman aqueduct. Pointed arches were most often used by builders of Gothic-style architecture. The advantage to using a pointed arch, rather than a circular arch, is that the arch action in a pointed arch produces less thrust at the base. This innovation allowed for taller and more closely spaced openings, typical of Gothic architecture Vaults are essentially "adjacent arches [that] are assembled side by side." If vaults intersect, complex forms are produced with the intersections. The forms, along with the "strongly expressed ribs at the vault intersections, were dominant architectural features of Gothic cathedrals." The parabolic arch employs the principle that when weight is uniformly applied to an arch, the internal compression resulting from that weight will follow a parabolic profile. Of any arch type, the parabolic arch produces the most thrust at the base, but can span the largest areas. It is commonly used in bridge design, where long spans are needed.

1. Prof. Crisencio M. Paner, MSc.

2.  An arch is a structure that spans a space and
supports structure and weight above it.
 Arches appeared as early as the 2nd millennium
BC in Mesopotamian brick architecture and their
systematic use started with the Ancient Romans
who were the first to apply the technique to a wide
range of structures.
A masonryarch
1. Keystone 2. Voussoir
3. Extrados 4. Impost
5. Intrados 6. Rise 7. Clear span
8. Abutment

3.  Arches have many forms, but all fall into three
basic categories: Circular, pointed, and
parabolic.
Circular Arch Pointed Arch Parabolic Arch

4.  Arches with a circular form, also referred to as
rounded arch, were commonly employed by the
builders of ancient history, heavy masonry arches.
 Ancient Roman builders relied heavily on the
rounded arch to span large, open areas.
 Several rounded arches placed in-line, end-to-end,
form an arcade, such as the Roman aqueduct.
Roman aqueduct near Nîmes, France
Horseshoe arches (9th century) in the
Mosque of Uqba, in Kairouan, Tunisia

5.  Pointed arches were most often used by builders
of Gothic-style architecture.
 The advantage to using a pointed arch, rather than
a circular arch, is that the arch action in a pointed
arch produces less thrust at the base.
 This innovation allowed for taller and more closely
spaced openings, typical of Gothic architecture
Cathedralof St. Michael and St. Gudula in
Brussels,Belgium, with its central, pointed
archwindow, typical of Gothic architecture.

6.  Vaults are essentially "adjacent arches [that] are
assembled side by side."
 If vaults intersect, complex forms are produced
with the intersections.
 The forms, along with the "strongly expressed ribs
at the vault intersections, were dominant
architectural features of Gothic cathedrals."
Interiorvaulted ceiling of Notre Dame de
Paris,showingthe ribs at the intersection
of several arches.

7.  The parabolic arch employs the principle that
when weight is uniformly applied to an arch, the
internal compression resulting from that weight will
follow a parabolic profile.
 Of any arch type, the parabolic arch produces the
most thrust at the base, but can span the largest
areas.
 It is commonly used in bridge design, where long
spans are needed.
Sandö Bridge in Sweden: Example of a
parabolicarch used to span a large area.

8.  True arches, as opposed to corbel arches, were
known by a number of civilizations in the Ancient
Near East, the Levant, and Mexico, but their use
was infrequent and mostly confined to
underground structures such as drains where the
problem of lateral thrust is greatly diminished.
Arch of the Near East
Arch of Levant
Mayan Corbel Arch

9.  A rare exception is the bronze age arched city gate of
Ashkelon (modern day Israel), dating to ca. 1850 B.C.
 An early example of a voussoir arch appears in the
Greek Rhodes Footbridge.
 In 2010, a robot discovered a long arch-roofed
passageway underneath the Pyramid of Quetzalcoatl
which stands in the ancient city of Teotihuacan north
of Mexico City, dated to around 200 AD
City gate of Ashkelon Greek Rhodes Footbridge. Arch-roofed passageway
underneath the Pyramid
of Quetzalcoatl

10.  The ancient Romans learned the arch from the
Etruscans, refined it and were the first builders to tap
its full potential for above ground buildings.
 Throughout the Roman empire, their engineers erected
arch structures such as bridges, aqueducts, and gates.

11.  They also introduced the triumphal arch as a
military monument.
 Vaults began to be used for roofing large interior
spacessuch as halls and temples, a function which
was also assumed by domed structures from the
1st century BC onwards.
Arch of Constantine, Rome Arch of Triumph in Genoa,
Italy

12.  The arch is important because it is a marvelous way to
structurally support the mass of a building roof, a railway
line, or an aqueduct, like the ones the Romans built.
 Some of the arches built by Ancient Romans still stand
today, and they offer a mute testament to the effectiveness
of the arch in engineering.
 The arch is still in wide use today, and we even see big
glue-lams (wood glued to laminate it to make large beams)
in the shape of arches.
 The arch has a long history in structures man has built

13. BACKGROUND OF PROF. CRISENCIO M. PANER:
•Ph.D. in BiologicalScience (Candidate),UST
•M.S. in Microbiology,UST
•B.S. Biochemistry, UST
•ItalianGovernmentScholar
•CollegeScholar
•Certificatein Education
•10th Placer Licensure Exams for Teachers
•20 years of experience as a teacher (College, High School, Elementary)
•Expert in Internet, Computer (Software, Hardware, and Repair)
•Researcher and Blogger
•Art Restorer/Conservator
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