An arch is a structure that spans an opening and supports the weight above it using wedge-shaped units called voussoirs. Arches are classified based on their shape, number of centers, and materials used. Common shapes include segmental, semicircular, pointed, and horseshoe. Arches can have one, two, three, four, or five centers. They can be made of stone, brick, or concrete. Stone arches use rubble or ashlar stones while brick arches can be rough, axed, gauged, or purpose-made. Concrete arches are either precast block units or cast-in-place monolithically.

1. TYPE OF ARCHES
Ankit Shukla
ACA,Agra

2. ARCH
What is an Arch?
 An Arch is a structure constructed of
wedge-shaped unit.
 It spans an opening to support the
weight of the wall and other
superimpose load.
B.C.Punmia
Google.com
Reference-

3. Terminology
1. Intrados:- This is an inner curve
of an arch.
2. Extrados:- Outer Curve of an
arch
3. Soffit:- Inner Surface of an arch.
4. Voussoirs:- These are wedge
shaped units.
5. Crown:- Highest part of extrados
B.C.Punmia
W.C.MacKay
Reference-

4. 6. Spandril:- Curved triangular
space form between extrados and
horizontal line.
7. Key:- Wedge-shaped unit fixed
at the crown of the arch.
8. Skew back:- It is inclined or
splayed surface on the abutment.
9. Springing points:- These
are the points from which the
curve of the arch spring.
10. Springing line:- It is an
imaginary line joining the
springing point of either ends.
Reference- B.C.Punmia
W.C.MacKay

5. 11. Abutment:-End point of
an Arch.
12. Springer:- It is the first
voussoir at springing level.
13. Pier:-Intermediate support
of an archade.
14. Arcade:- It is a row of
arches in continuation.
15. Haunch:-Lower half of the
arch between the crown and
skew back.
Reference- B.C.Punmia
W.C.MacKay

6. 16. Ring:-It is the circular course
forming an arch.
17. Impost:- It is the projecting
course at upper part of pier or
abutment to stress the springing
line.
18. Bed Joint:-Joints between the
Voussoirs which radiate from
centre.
19. Centre or Stricking
Point:- This is geometrical
centre point from where the arc
forming the extrados, arc rings,
intrados.
20. Span:-Clear horizontal distance
between the supports.
Reference- B.C.Punmia
W.C.MacKay

7. Arches are classified according to:-
1. Shape
2. Number of Centers
3. Workmanship and Material Used
Reference- B.C.Punmia
Google.com

8. Classification According to Shape
Flat Arch Segmental Arch
Semi-circular Arch
Pointed Arch
Florentine Arch
Stilted Arch
Horse Shoe Arch
Venetian Arch
Relieving Arch
Semi-Elliptical Arch
Reference- B.C.Punmia
Google.com

9. Flat Arch
 Forms an equilateral triangle with intrados as base( at an angle of 60°)
 Used only for light loads
 Weakest Arch
Reference- B.C.Punmia
Google.com

10. Segmental Arch
 Center of Arch lies below springing line.
 Thrust transferred to the abutment is in inclined direction.
 Most Common type of Arch.
Reference- B.C.Punmia
Google.com

11. Semi-circular Arch
 Center Lie on Springing line
 Shape of the arch is Semi-circular
 Thrust transferred to the abutment is perfectly in vertical direction
Reference- B.C.Punmia
Google.com

12. Horse Shoe Arch
 The arch has the shape of a horse shoe.
 Incorporating more than a semi circle.
 Mainly use for Architectural consideration.
Reference- B.C.Punmia
Google.com

13. Pointed Arch
 Also known as Gothic Arch.
 It consist two arc of the circle meeting at apex.
 Triangle form may be equilateral or isosceles(also known as Lancet
Arch).
Reference- B.C.Punmia
Google.com

14. Venetian Arch
 This is another form of Pointed Arch.
 Has deeper depth at crown than springings.
 It Has four centers located on springing line.
Reference- B.C.Punmia
Google.com

15. Florentine Arch
 This is similar to Venetian Arch.
 Its intrados is a semicircle.
 It has three centers located on springing line.
Reference- B.C.Punmia
Google.com

16. Relieving Arch
 The ends of Arch carried sufficiently into abutment.
 Its lintel can be replaced without effecting the Arch.
 The Arch is constructed on either flat arch or wooden lintel.
Reference- B.C.Punmia
Google.com

17. Stilted Arch
 An arch whose curve begins above the impost line.
 It consists a semi circular arch with two vertical portions at springings.
 The centre of the arch lies on the horizontal line.
Reference- B.C.Punmia
Google.com

18. Semi-Elliptical Arch
 It has shape of semi-ellipse.
 It has either three centre or five centre.
 Also called a basket-handle arch.
Reference- B.C.Punmia
Google.com

19. Classification According to Number Of
Centers
One-Centered Arch
Two-Centered Arch
Three-Centered Arch
Four-Centered Arch
Five-Centered Arch
Reference- B.C.Punmia
Google.com

20. One-Centered Arch
 It has only one center.
 Segmental Arches, Semicircular Arches, Flat Arches, Horse Shoe
Arches and Stilted Arches come under this Category.
 Sometimes full circular arch (Bulleye Arch ) provided for circular
windows.
Reference- B.C.Punmia
Google.com

21. Two-Centered Arch
 It has two centers.
 Pointed Arches comes under this category.
 Semi-elliptical arch and Florentine arch also comes under this category.
Reference- B.C.Punmia
Google.com

22. Three-Centered Arch
 It has three centers.
 Elliptical Arches comes under this category.
 Equilateral Arches also comes under this category.
Reference- B.C.Punmia
Google.com

23. Four-Centered Arch
 It has four centers.
 Venetian arch comes under this category.
 Another example is Tudor arch.
B.C.Punmia
Google.com
Reference-

24. Five-Centered Arch
 It has five centers
 Fives centers help in getting a good semi- elliptical shape
Reference- B.C.Punmia
Google.com

25. Classification Based On Material And
Workmanship
Stone Arch Brick Arch
Concrete Arch Reference- B.C.Punmia
Google.com

26. Stone Arch
1. Rubble Arches
 Weak and use for comparatively inferior
work.
 Made by stones which are dressed, roughly
shaped and sized as voussoirs
 Mortar is used for binding stones
2. Ashlars Arches
 Made by stones which are fully dressed and
in proper shape of voussoir.
 Lime or cement mortar is use as binding
material.
 Use for making Flat arches
Reference- B.C.Punmia
Google.com

27. Brick Arches
1. Rough Arch
 Made with ordinary bricks
 Joints are wedge-shaped with
greater thickness at extrados and
smaller thickness at intrados.
 Not used for exposed brick work.
2. Axed or Rough-cut Arch
 Made with wedge shaped bricks
 Joints are of uniform thickness.
 Not so attractive due to wedge
shaped bricks which are not finely
dressed.
Reference- B.C.Punmia
Google.com

28. 3. Gauged Arch
 Made with bricks which are prepared to
exact size and shape of voussoir.
 Joints are fine , thin and truly radial.
 Lime putty is use as a binding material.
4. Purpose made brick Arch
 Made with special bricks which are
manufactured in exact shape and size of
voussoirs.
 This is very fine workmanship.
 Lime putty is used as a binding material.
Reference- B.C.Punmia
Google.com

29. Concrete Arches
1. Concrete block-unit Arch
 Made with pre casted concrete
blocks.(moulds in shape of voussoirs)
 Good appearance and size of arch
achieved due to perfections.
 Cement mortar is used as a binding
material and joints are thin.
2. Monolithic Arch
 Made with cast-in- situ concrete, either
plain or reinforced.
 Suitable for large span.
 The thickness is 15cm for arches upto
3m span.
Reference- B.C.Punmia
Google.com