Port City International University(Department of CIVIL

ENGINEERING)SUBJECT: DETAILS OF CIVIL CONSTRUCTION

NAME:MUTHMAYEEN MOHSIN

ID:CEN 00505249

05/03/2023

Subjects of My Presentation:

Retaining Wall

Cofferdam

Caisson

Retaining Wall

Retaining walls are structures design to restrain soil to unnatural slopes.They are used to bound soils in areas where the landscape needs to be shaped severely.

Types of retaining wall

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Gravity WallGravity Wall is Standard wall type that holds the earth mainly through its own weight.

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Piling WallUsing long piles

this wall is fixed by soil on both sides.If the pile themselves can resist the bending forces this wall can take high loads.

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Cantilever Wall

The cantilever wall uses the same earth pressure trying to topple it to stabilize itself with a second lever arm.

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Anchored WallThis wall keeps it from toppling by having cables driven into the soil or rock.Fixed by expanding anchors.

Gravity Retaining Walls

Gravity walls depend on their mass (stone, concrete or other heavy material) to resist pressure from behind.

Sheet pilingSheet pile retaining walls are usually used in soft soils and tight spaces.

Sheet pile walls are made out of steel, vinyl or wood planks which are driven into the ground.

Cofferdam

A cofferdam (also called a coffer) is a temporary enclosure built in pairs across, a body of water and constructed to allow the enclosed area to be pumped out, creating a dry work environment for the major work to proceed.

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Types Of Cofferdam(a) Earthen cofferdam(b) Rock-fill cofferdam(c) Single-walled cofferdam(d) Double-walled cofferdam(e) Crib cofferdam(f) Cellular cofferdam

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Earthen Rockfill

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Single Walled Double Walled

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Cellular: (i) Circular type cellular cofferdam.(ii) Diaphragm type cellular cofferdam.

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Crib Cofferdam

Dam Construction

For the Dam construction, two cofferdams are usually built, one upstream and one downstream of the proposed dam.

Cofferdam in Ship

The cofferdam is also used on occasion in the shipbuilding and ship repair industry. In some cases a ship is actually cut in two while still in the water, and a new section of ship is floated in to lengthen the ship.

Portable cofferdams: Portable cofferdams are inflatable cofferdams that can be reused.

Cofferdams of this type are stretched across the site,Then inflated with water from the prospected dry area.

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How Cofferdam Works

CaissonIn geotechnical engineering,

A caisson is a watertight retaining structure used.

For example, To work on the foundations

of a bridge pier, for the construction of a concrete dam,or for the repair of ships.

These are constructed such that the water can be pumped out, keeping the working environment dry.

Types

The three main types of caisson are :OpenBoxPneumatic caisson

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Open CaissonThis type of caisson has the distinction of being employed for the deepest foundation for, bridge piers, abutments and other similar structures.

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Box Caisson This type of caisson is similar to open caisson except that it is closed at bottom. The caisson is cast and cured on land and when required, it is launched in water and towed to the site for sinking

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Pneumatic CaissonThis type of caisson is closed at top and open (during construction) at the bottom. The water is excluded from the caisson chamber by means of compressed air.

Dangers encountered in pressurized caissonsCaisson disease has been

named since it appeared in construction workers when they left the compressed atmosphere of the caisson.

Construction of the Brooklyn Bridge, which was built with the help of caissons, resulted in numerous workers being either killed or permanently injured by caisson disease during its construction.

Other uses Caissons have also been used in the installation of hydraulic elevators where a single-stage ram is installed below the ground level.

How caissons workShallow caissons may be open to

the air, whereas pneumatic caissons, which penetrate soft mud, are sealed at the top and filled with compressed air to keep water and mud out at depth. Then an airlock allows access to the chamber. Workers move mud and rock debris (called muck) from the edge of the workspace to a water-filled pit, connected by a tube (called the muck tube) to the surface. A crane at the surface removes the soil with a clamshell bucket.

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How Caisson Works

Conclusion