A SEMINAR PRESENTATION ON

“BRIDGE CONSTRUCTION”

Submitted By:Robin Nirwal+6

Submitted To:

BridgeBridge is a structure that provides passage over obstacles such as valleys, rough terrain or bodies of water by spanning those obstacles with natural or manmade materials.

They first begun be used in ancient times when first modern civilizations started rising in the Mesopotamia.

In the beginning bridges were very simple structures that were built from easily accessible natural resources- wooden logs, stone and dirt

700 A.D. Asia

1,304 years ago

100 B.C. Romans2,104 years ago

Clapper BridgeTree trunkStone

Arch design evenly distributesstressesNatural concrete made from mud and straw

Roman Arch Bridge

History of Bridge Development

Great Stone Bridge in China

Low bridgeShallow archAllows boatsand water to passthrough

History of Bridge Development

Truss BridgesMechanics of DesignWood

Suspension Bridges

Use of steel in suspending cables

1900

1920

Pre stressed ConcreteSteel

2000

Compression Tension

Basic Concepts

Span - the distance between two bridge supports, whether they are columns, towers or the wall of a canyon.

Compression –

Tension -

Force -

Concrete has good compressive strength, but extremely weak tensile strength. What about steel cables?

Basic Concepts

Beam - a rigid, usually horizontal, structural element

Pier - a vertical supporting structure, such as a pillar

Cantilever - a projecting structure supported only at one end, like a shelf bracket or a diving board

Beam

Pier

Load - weight on a structure

Survey of Bridge

A preliminary survey is made at the best site to establish horizontal and vertical control and to obtain information for the bridge design and construction planning.

Bridge surveying is necessary to locate a site, obtain information for design, and furnish lines and grades for construction.

A Foundation is the lowest and supporting layer of a structure.

Foundation are generally divided into two categories : Shallow Foundation Deep Foundation

SHALLOW FOUNDATIONThere are variety of shallow foundation types used in construction of foundationColumns$ Combined or Cantilevered$ Mat$ Wall (strip)$ Spread Footing$ Strap Footing

Deep Foundati on are those foundati on in which the depth pf the foundati onIs very large in comparison to its width.

Types of deep Foundati on€Deep strip ,rectangular and square footi ng€Pile Foundati on€ Pier Foundati on or dri l led Caissan Foundati on€ Well Foundati on or Caissan

Pile Foundation

Types of Pile FoundationPiles may be classified as follows•Classification based on function•Classification based on material and compaction

CLASSIFICATION BASED ON FUNCTIONBased on the function or the use piles may be classified•End Bearing•Friction Piles•Compaction Piles•Tension Or Uplift Piles•Anchor Piles•Fender Piles•Sheet Piles

END BEARING PILES

If the loads is transferred through soft soil or water to a suitable bearing stratum by means of end bearing piles it is known as end bearing piles and point piles.

FRICTION PILESIf the loads is transferred to a depth of the relatively weak soil by means of friction along the length of the piles it is known as friction piles.

COMPACTION PILES

Piles are also used for compacting loose granular deposit these piles are short and as known as compaction.

TENSION PILESSometimes piles are used to resist upward forces these piles are subjected to tension are known as tension piles.

ANCHOR PILESAnchor piles are slender foundation elements that can be installed vertically. They can transfer both compressive and tensile forces to the ground, which makes them ideal as vertical anchors for basements and tunnels

FENDER PILESHarbor Piles excel when used in foundering applications. The nature of fiberglass lends itself to high energy absorption and recoverable deflection

SHEET PILES

Sheet piling is an earth retention and excavation support technique that retains soil, using steel sheet sections with interlocking edges.

BATTER PILESIn case of large lateral loads or inclined force, piles driven at an angle resist force effectively these are called batter piles

TYPES OF PILE CHOSEN DEPENDS ON FOLLOWING FACTORS

What type of pile is readily available ∞ Location & Type of structure (Magnitude of loading)∞ Ground Connation (Soil Type)∞ Cost∞ Durability

TYPES OF WELL FOUNDATION OR CASSION¥ Box Caissons¥ Excavated Caissons¥ Floating Caissons¥ Open Caissons¥ Pneumatic Caissons¥ Sheeted Caissons

METHOD OF INSTALLATION¤ Dropping Weight or Drop Hammers Commonly Used methodOf insertion of displacement piles

¤ Diesel HammersMost Suitable to drive Pile in non cohesive granular soil

¤ Vibratory Hammers or Vibratory Method of pile driving Very effective in driving piles through non cohesive granular soil

¤ Jacking Method of Insertion

Dropping Weight/Drop Hammers€ A weight approximately half that of the pile is raised a suitable distance in a guide and released to strike the pile head.€ When driving a hollow pile tube the weight usually acts on a plug at the bottom of the pile thus reducing any excess stresses along the length of the tube during insertion.

Diesel Hammer Rapid Controlled explosion can be produced by the diesel hammer The explosions raise a ram which is used to drive the pile into the ground. although the ram is smaller than the weight used in the drop hammer.Increased frequency of the blows can make up for this inefficiency.This type of hammer is most suitable for driving piles through non-cohesive granular soil where the majority of the resistance is from end bearing.

Vibratory Method Of Pile DrivingVibratory methods can prove to be very effective in driving piles through nonCohesive granular soils.The vibration of the pile excites the soil grains adjacent to the pile making theSoil almost free flowing thus significantly reducing friction along the pile shaft.However the large energy resulting from the vibrations can damages equipment,Noise and vibration propagation can also result in the settlement of near by buildings.

Jacking Method of Insertion

Jacked Piles are most commonly used in underpinning structure.By excavating underneath a structure short lengths of pile can be inserted and jacked into the ground using the underside of the existing structure as a reaction.

PRECAST SEGMENTAL ERECTION TECHNIQUES

1. Erection on False work2. Erection by Gantry3. Erection by Crane4. Erection by Lifting Frame5. Full Span Erection Techniques

ERECTION ON FALSEWORK

ERECTION BY GANTRY

ERECTION BY CRANE

ERECTION BY LIFTING FRAME

FULL SPAN PRECAST ERECTION TECHNIQUES