Classification Based on Number of Centres
On the basis of number of centres, the arches might be categorized as:
One-centred Arches
These arches have one centre only. Segmental arches, semi-circular arch, flat arches, horse-shoe arch and stilted arches come under this category. Sometimes, a perfectly circular arch, known as bull's eye arch as shown in Figure 10(a), is provided for circular windows.
![1551_Classification Based on Number of Centres.png](https://www.expertsmind.com/CMSImages/1551_Classification%20Based%20on%20Number%20of%20Centres.png)
Figure : Arches Based on Number of Centres
Two-centred Arches
These arches are of several types but the popular ones are pointed arches and florentine arch as shown in Figures 9(e) and (g).
Three-centred Arches
Elliptical arches come under this category. Figure (b) shows a three-centred arch.
Four-centred Arch
It has four centres. Venetian arch is a classic example of this type. Other examples are the Tudor arch as in Figure (c).
Five-centred Arch
This type of arch, having five centres, gives a good semi-elliptical shape as is shown by Figure (d).