ABUTMENTS :-

           Ab abutment is a structure located at the end of a Bridge. The basic functions of an abutment are:

• Supporting the bridge Deck at the ends
• Retaining the approach road embackment
• Connecting the approach road to the bridge Deck

           There are different types of abutments. The selection of a perticular form of abutment depends on the geometry of the site and the size of the bridge. The simplest form of an abutment is a wall of considerable thickness provided with bridge seating arrangement at the top. A major difference b/w a conventional retaining wall and an abutment is that, an abutment is always associate with additional walls called WING WALLS. The major types of abutments currently  in use are explained below

Gravity Abutment :-

           A gravity Abutment resists horizontal earth pressure from the rear, with its own dead weight. To be stable, this leads to massive-sized abutment. These abutment may be of mass concrete or stone masonry. A gravity Abutment is composed of a back wall and splayed wing walls, which rest on foundation. The cross-section of this type of abutment is shown in below fig.....

U-Abutment :-

           When the wing walls of gravity Abutment are placed at the right angle to the back wall, the abutment is known as U-Abutment. The name U-Abutment is due to the Shape of this Abutment in plan. The wing walls are typically cast monolithically with the abutment back wall and cantilevered both vertically and horizontally. As shown in below fig...

Stub Abutment :-

           Stub Abutment are relatively short abutments, which are placed on top of the embackment or slope. Sufficient rocky terrain must prevail at the site, so that the stub Abutment can be support on piles which extend through the embackment. This is portrayed in Fig..

Counterfort Abutment :-

           A Counterfort Abutment is a very much similar to a Counterfort retaining wall. In Counterfort Abutment, a thin wall called counterfort connect the breast wall to the footing. These Counterfort are spaced at regular intervals so that the breast wall is designed as a supported slab rather than as a cantilever. Counterfort Abutment are used when high Abutments are required. This type of Abutment is shown in fig.....

Abutment

Tunnel