Engineering SystemENG001

Case study on

BRIDGES

Civil Engg. GroupTEQIP-II Institutions

Session-1

1. Tension - a force which acts to

expand or lengthen the thing it is

acting on.

2. Compression - a force which acts to

compress or shorten the thing it is

acting on.

Concepts

Compression Tension

Session-1

3. Bending - When something pushes

down on the beam, the beam

bends. Its top edge is pushed

together, and its bottom edge is

pulled apart.

4. Stresses

5. Deflection

Concepts

Session-2

6. Span- the distance between two

bridge supports, whether they are

columns, towers .

7. Factor of safety

8. Loads

Concepts

L= Length of Bridge

Session-2

ConceptsFreeboard The difference between H.F.L. (allowing afflux) and formation level of

road embankment on approaches.

H.F.L. Highest flood level is the level of highest flood ever recorded or the calculated level for design discharge.

Afflux The rise in the flood level of the river immediately on the upstream of a bridge as a result of obstruction to natural flow caused by the construction of bridge and its approaches.

Session-3

What is a need of Bridges?

• A bridge is a structure providing passage over an obstacle without closing the way beneath. The required passage may be for a road, a railway, pedestrians, a canal or a pipeline. The obstacle to be crossed may be a river, a road, railway or a valley.

• In other words, bridge is a structure for carrying the road traffic or other moving loads over a depression or obstruction such as channel, road or railway.

Session-3

Historical Background

Primitive Peoples:Logs

Slabs of Rocks

Intertwined Vines or Ropes

Roman EmpireFirst Great Bridge BuildersTimber Truss Bridges

Masonry Arch Bridges

EuropeansFollowed HRE Until Iron and Steel Use

Nineteenth Century—Modern Long Bridges

Moveable Bridges

Session-3Famous Bridges

Millau Viaduct, France:Erasmus Bridge, Rotterdam : 808 m long, 32 m wide & 343 m high

Sutong Bridge, China : 8206 m long

Akashi Bridge, Japan : 3911 m long

Session-3

Components of Bridges

Components of Bridges

VARIOUS TYPE OF FOUNDATIONS

A. Foundations

Shallow Foundations

1. Open foundations : Hard Strata is met at Shallow Depth or depth of foundation is upto 5 to 6 m.

2. Raft foundations : Foundation Strata is weak having low SBC

Deep Foundations

1. Pile Foundations: Hard strata is not available at shallow depth and scour depth is considerable.

2. Well Foundations: Hard strata is not available at shallow depth, scour depth is considerable and foundation is in water (may be river, sea).

Components of Bridges

Sinking of Well Foundation

Boring of Pile Foundation Casing of Pile Foundation

Components of Bridges

Various Type of Substructures Abutment

o Cantilever wall type RCCo Gravity type PCCo Counter fort typeo Spill through typeo Box type

Pierso Wall typeo Circular typeo Semi circular typeo Y-shape type

Wing wall / Return wallo Cantilever wall type RCC and PCCo Counter fort typeo Box typeo RE Wallo Gabion Wall

Toe wall –RCC and PCC type

B. Substructures

Components of BridgesB. Substructures

Cross Section of Pier with Pile Foundation

Cross Section of counterfort Abutment

Components of BridgesB. Substructures

Counterfort type Abutment

Wall type Abutment

Components of BridgesB. Substructures

Circular Type Pier Wall type Pier

C. Superstructures

Components of Bridges

Earlier practice for Superstructure: Girders and slab system or Box girders were designed & used Girders & slabs system was more prominent due to majority

bridges being of small / moderate spans.

Emerging design trend for Superstructure is

Long span bridges Continuous structures Segmental construction

o Cast-in-situo Pre-cast

Steel / concrete composite constructions Extra dosed cable stayed structure to bridge longer span with

shorter depths Cable stayed bridges Suspension bridges

C. Superstructures

Components of Bridges

Solid Slab type Superstructure

Voided Slab type Superstructure

C. Superstructures

Components of Bridges

RCC Multi-girder slab system

PSC Multi-girder slab system

C. Superstructures

Components of Bridges

PSC Box type Superstructure

Steel type of Superstructure

C. Superstructures

Components of Bridges

Cable Suspension

Bow String Girder

C. Superstructures

Components of Bridges

PSC Box type Superstructure

Balance cantilever type Superstructure

Classification of Bridges Bridges may be classified in many ways, as below:

According to the functions as aqueduct (canal or a river), viaduct (road, railway over a valley) pedestrian, highway, railway, road cum rail or a pipeline bridge.

According to material of construction of superstructure as timber, masonry, iron steel, RCC, PSC, composite etc.

According to form of superstructure as slab, girder(T girder, Box girder), truss, arch, cable stayed or suspension bridge.

According to inter-span relations as simple, continuous or cantilever. According to the road level relative to the highest flood level of the river

below, particularly for a highway bridge, as high level or submersible bridge. According to the length of bridge

Length > 60m major bridges, 60m > Length > 6m minor Bridges, 6 > span Culverts.

According to the anticipated type of service and duration of use as permanent, temporary, military (pontoon, Bailey) bridge.

Session-4

Classification of Bridges

According to the functions as aqueduct (canal or a river), viaduct (road, railway over a valley), pedestrian, highway, railway, road cum rail or a pipeline bridge.

Canal Bridge Pedestrian Bridge

Railway Bridge

Classification of Bridges

Highway Bridge (Flyover)

Railway Over Bridge

River Bridge

Classification of Bridges

According to material of construction of superstructure as timber, masonry, iron steel, RCC, PSC, composite etc.

Iron Steel Bridge RCC Bridge

Timber Bridge Masonry Bridge

Classification of Bridges

According to form of superstructure as slab, girder (T-girder, Box girder), truss, bridge.

Slab Bridge Truss Bridge

Box girder bridge

T Girder Bridge

Classification of Bridges

According to form of superstructure as arch, cable stayed or suspension bridge.

Arch Bridge

Cable Stayed Bridge

Suspension Bridge

Classification of Bridges

According to inter-span relations as simple, continuous or cantilever.

Balanced Cantilever Bridge

Continuous Girder Bridge

Classification of Bridges

According to the road level relative to the highest flood level of the river below, particularly for a highway bridge, as high level or submersible bridge.

High Level Bridge

Submersible Bridge

Classification of Bridges According to the anticipated type of service and duration of use as permanent,

temporary, military (pontoon, Bailey) bridge.

Pontoon type temporary Bridge Temporary Bailey Bridge

Temporary Military Bridge

Session-5

Data Collections for Bridges

1. Hydraulic data2. Site selection3. Type of Bridges4. Loading (IRC Standards)5. Materials6. Construction Techniques7. Economy8. Most Economical Span

Session-6

State-of the Art in Bridges

1. Takanaka nerrows Bridge- Japan2. Various failure of bridges in world and India

References

• Principles and Practice of Bridge Engineering By S. P. Bindra. Dhanpatrai publication

• Bridge Engineering by S. C. Rangwala. Charotar Publication

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