PRESENTATION ON bridge ENGINEERING

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So… What is a Bridge?Bridge:-

A bridge is a structurecarrying a road, path, railroad, or canal across

a river, ravine, road, railroad or other obstacle.

So… What is (also) a Bridge?bridge:

A bridge can also be a time, place, or means of connectionor

transition.

So…What is Engineering?

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engineering :

The branch of science and technology concerned with

the design, building, and use of engines, machines, and

structures.

• The work done by, or the occupation of, an engineer.

• The action of working artfully and professionally to bring

something about.

What is Bridge Engineering?

The field of science and technology applied to the design and

construction of a structure carrying a road, path, railroad,

or canal across a river, ravine, road, railroad or other obstacle.

What is Bridge Engineering?

If a bridge can also simply be a means of connection, then bridge

engineering is also a recognition of the history of human

civilization as a story of travel and transportation.

So…What is (also) Bridge Engineering?

The building of crossings in the form of bridges has always been a

measure of technological development of a people.

So…How do Bridges and Bridge Engineering Work?

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1. Need

2. Location

3. Material

4. Analysis / Design

5. Construction

NeedThe need could be driven by many different sources.

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• New demands: development or planned development of

an area or migration of people and goods which require

transportation

• Changing demands: existing conditions good for

yesterday no longer meet what is necessary today or

tomorrow.

Need

10Map of Rock Island, IL, 1889 (H. Wellge)

Map of Rock Island, IL

2016 (Bing)

LocationThe location could be driven by many different sources.

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• Population density

• Favorable site conditions for the structure

• Vicinity of other alternate routes

Location

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MaterialIn our application of science and technology, we use many

different kinds of materials.

We need to understand the behavior of everything that

goes into the completed structure.

Material

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Material

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• Concrete

• Steel

• Timber

• Steel Wire / Cable

• Connections

– High-strength Bolts

– Rivets

– Welding

• Exotic materials

– Bearings

– Collision protection

Material

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Huey P. Long Bridge Widening

Material

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“...Concrete...”

“...and even both together.”

Huey P. Long Bridge Widening

Analysis and Design

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“...We deal with people.”

“...but also have

homework to do.”

Construction

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Huey P. Long Bridge Widening

“Do you understand how things go together...

...In complex ways?”

Bridge Engineering (also) is...About Solutions

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Whatever structure we design and will get built needs to

take into account the diverse elements which will

impose demands on it.

• Vulnerability to earthquakes

• Vessel collisions

• Scour

• High Winds...

• ...and unfortunately, acts of terrorism...

• ...or other problems...

Bridge Engineering (also) is...Part of Larger Civil Engineering Field

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We apply the practice of several specific fields of

engineering including:

• Structual Engineering

• Geotechnical Engineering

• Traffic and Transportation Engineering

Along with...

• Economics

• Law

• Public Policy

• Culture/Aesthetics

Dragon Bridge (Vietnamese: Cầu Rồng) is a bridge over

the River Han at Da Nang, Vietnam

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Why Civil Engineering?“Civil engineers make civilization possible.”

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Why Would You Choose Bridge Engineering?

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So What’s the Bottom Line?

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Stability: When things are good, people build. When times are tough, the

public looks to “shovel ready” and other large-scale public works projects.

Job Security: The interstate highway system began construction in 1956.

Much of our nation’s infrastructure is approaching its original design life.

There is a need to extend what we have, and build or rebuild new.

ASCE’s 2013 Infrastucture Report Card received a “D+” average! There is a

need and it’s growing.

Personal Satisfaction: If you want to help build great things that everyone

sees, helps entire communities, cities, regions, states, or even countries, then

this is your profession.

We need more engineers...You can be next.

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Selection Criteria For Bridge Site

Selection Criteria For Bridge Site

1.The choice of the right site is a crucial

decision in the planning and designing

of a bridge.

2.It may not be possible always to have a

wide choice of sites for a bridge.

3.This is particularly so in case

of bridges in urban areas and flyovers.

4.For river bridges in rural areas, usually a

wider choice may be available.

Components and Parts of Bridge

Main components of the modern bridges are:

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Abutment – Endpoints of the bridge. They arereinforced so that they can endure intense lateralpressures.Pile (also known as beam, footing, and pier) –Reinforced concrete post that is driven into the groundto serve as the leg or support for the bridge. Thedistance between piles is calculated so that is cansupport the rest of the structure that will be laid ontop of them.Cap – Cap sits on top of the pile beam, providingadditional support and dispersing the load to the pilesbelow. The combination of Pile and Cap elements iscalled Bent.

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Girder or Span – One of the main components of the

bridge that connects all the Piles beams. It can consist

from multiple simple spans, a single continuous span that

is supported by multiple beams, cantilever spans and

cantilever spans with the suspended span between them.

They are usually made from metal or reinforced concrete

and also can be made in the form of haunches girded that

can carry more load. Girder sections are typically not

made from a simple block of material but are made from

truss network (or Orthotropic beams) that increases their

resistance to load. Girders can also be used as a part of

rigid frame network where they are fully connected with

frame legs (which can be inclined or in V shape).

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Superstructure truss network – Truss network that supports travel surface can be made in three basic ways – Deck truss where traffic flows on top of truss network, Pony truss where truss network flows between two parallel walls of trusses, and Through truss that adds additional cross-braced truss network above and below the traffic.

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Arch – Arches on the bridges are distinguished by the number of hinges they have (usually between zero or three) which determine how much stress and load they can safely carry, and the type of material they are constructed (solid material, truss system). Arches below the bridge are called spandrel-braced (cantilever) or Trussed deck arch. Arch bridges can also use suspension bridges where the arch is made from truss system (tied arch, or bowstring bridge).

Spandrel – Spandrels are the almost triangular space between the main pillar of the bridge and decking. Stone bridges use filled “closed” spandrels deck arches, while modern bridges made from metal use open spandrel deck arch configurations.

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Truss – Framework made by connecting triangles and other forms that share load and stress forces across its entire structure. They are commonly separated into several categories such as simple truss (King and Queen posts), covered bridge truss (multiple kingpost truss, Howe truss, long truss, Burr arch truss, town lattice truss, Haupt, Smith, Partridge and Child truss), Pratt truss (and it’s many variations), Whipple truss, Warren truss variations, Howe truss, Lenticulartruss, Fink truss, multiple Cantilever truss variations, and suspension truss arches.

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Permanent Bridge

These bridges are constructed for long term use and maintained at high level. Steel or R.C.C bridges are come under this category.

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Temporary BridgesTemporary Bridges are pre-engineered, modular

structures that can be used to cross anything from

drainage ditches, streams, and trenches to railway

lines, or utility pipes that are buried close to the

surface

Bridge Inspection & Maintenance

Bridge inspections (non-structural) are carried out by

qualified staff and reports are prepared that identify

minor routine maintenance and repair items to be

rectified. In addition, the local area surrounding the

bridge is inspected for erosion problems, obstructions

to water flow and other general defects. Aside from

an annual inspection program, bridges may be

inspected following damage caused by accidents,

severe weather conditions, flooding and ice jams, or

where a known problem exists that requires regular

monitoring.36

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Bridge maintenance services provided by:-

1. Bridge cleaning and washing

2. Bridge deck sweeping

3. Bridge deck repairs (asphalt, concrete, and

timber deck surfaces)

4. Expansion joint maintenance and repair

(including bearings and bearing seats)

5. Erosion control

6. Obstruction removal for water flow

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Thank You

PRESENTATION ON tunnel ENGINEERING

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INTRODUCTION

Tunnels are underground passages used for transportation. They could be used for carrying freights and passengers, water, sewage, etc.

The methods involved are underground operations known as tunnel driving and the surface is not disturbed

It is understood that first tunnel was constructed by Egyptians and Babylonians about 4000 years ago. It was built to connect two buildings in Babylon. The length, width, and height of this tunnel were 910m, 360 cm, 450 cm respectively.

THAMES TUNNEL(LONDON)

Tunnels are more economical than open cuts beyond

certain depths

Tunnels avoid disturbing or interfering with surface life

and traffic during construction

Tunnels prove to be cheaper than bridges or open cuts to

carry public utility services like water, sewer and gas

if tunnels are provided with easy gradients, the cost of

hauling is decreased

In case of aerial warfare and bombing of cities, the

tunnels would grant better protection as compared to

bridges

In general it depends on relative cost of open tunnelvs tunelling some aspects are given below.

Nature of soil, particularly in deep cutting, with theconsequent side slopes and volume of excavation

If the soil is hard rock, the open cut could be of steepslope, involving much less volume of excavation andmay prove cheaper

The requirements of fill in the neighborhood alsolargely influence the choice. If a large amount ofmaterial is needed for the nearby fill, an open cutmay be justified

Alignment restraints: Underground space is a heterogeneous mass and in addition, problems like water table, position of fractured rocks etc. are to be tackled. A through detailed inspection and evaluation of the existing alignment restraints of underground space should therefore be made & correlated with the tunneling technology to be adopted for the project

Environmental considerations: The site of tunnel should be selected in such a way that the least difficulty is experienced for various environmental factors such as disposal of exhaustgas, groundwater, muck, etc.

Full face method: The full face method is adopted only for small tunnels whose dimensions do not exceed about 3 m. The vertical columns are fixed at suitable height. A series of drillholes about 10 mm to 40 mm diameter are drilled at about 1200 mm centres.

Heading & bench system: This is the method usually adopted for all railway tunnels. The heading is the top portion which will be 3700 mm to 4600 mm ahead of the bottom portion known as bench.

Cantilever car dump method: This arrangement consists of two plate girders about 23 m long and fixed at 1800 mm centres. A belt conveyor fitted with a number of jacks is running on these plate girders, the ends of which project beyond full face of the bench.

Drift system: In this system, a drift is first

driven of appropriate size, usually of 3000 mm

by 3000 mm. The drillholes are provided all

round the drift in entire cross section of tunnel.

Pilot tunnel method: The pilot tunnel which is

first driven to full size is connected to the

centre-line of the main tunnel, can be started

from a number of holes. The pilot tunnel also

helps in removal of muck and the lighting and

ventilation of the main tunnel

Forepoling method: In this method, a frame in the shape A is prepared and placed near the face of the tunnel covered with suitable planks. The poles are then inserted at top and continued to a depth upto which they can be easily taken up. The forepoling is an old method and it can be used successfully for carrying out tunnelling operations through ground

Needle beam method : This method is useful when the soil is hard enough to stand for few minutes. A small drift is prepared for inserting a needle beam consisting of two I-girders and bolted together with a wooden block in the centre.

METHODS OF TUNNELLING

THROUGH SUB-AQUEOUS STRATA

Shield tunnelling: A shield is a movable frame and it

is used to support the face of the tunnel. The

excavation & lining of tunnel can be carried out under

protection of shield

Plenum process or compressed air tunnelling: In this

process, the use is made of compressed air to prevent

the collapse of sides and the top of the tunnel.

Theoretically 0.003 N/mm² air pressure is equivalent

to 305 mm of head of water. But practically 0.0035

N/mm² pressure will be required.

DRAINAGE OF TUNNELS Sumps & pumps: The sumps connected by a pipe line

are provided at a distance of about 300 m & water is pumped from one sump to another until it is thrown out of tunnel opening

Grouting: The above method cannot be used, if water is percolating from the top of the tunnel. In such cases, the grouting is adopted to make the seams water-tight.

Pilot tunnel: In cases where pilot tunnel at a lower level than the main tunnel is constructed parallel to it for drainage of water

LIGHTING OF TUNNELS

The situations which demand adequate light can be

obstructions in tunnel, drilling & mucking

zones, bottoms of shaft, storage points, pumping

stations, underground repair shops

The spacing of lights will depend on various factors

such as tunnel dimensions, size of light source, nature

of rock surface

The common types of lights used in tunnelling work

are acetylene gas lighting, electric lighting & lanterns

SHAFTS & MUCKING

Shafts: The shafts are used for ventilation after

the construction of tunnel. They are also useful

to accommodate the pipes of fans during

construction work

Mucking: In case of tunnelling through

rocks, the blasted rock or earth has to be

removed from the tunnel. This process is

known as mucking

VENTILATION OF TUNNELS

Blow-in method: In this method fresh air is forced by a fan through a pipe & is supplied near face. This method has the advantage that a positive supply of fresh air is guaranteed where it is required.

Exhaust method: In this method the foul air is pulled out through a pipe & is exhausted by a fan. This sets up a current of fresh air to enter the tunnel. This method has the advantage that the foul air is kept out from working place.

INSIDE OF A TUNNEL

LINING OF TUNNELS

The lining will be required in practically all the tunnels to give a finishing touch to the tunnel cross-section. Most common materials used as lining are stones, bricks, cement concrete, rubber & pre-cast pipes.

In rocky ground, the lining can be carried out in any one of following ways:

Invert first and then sides & top

Side walls first and then arch section and then invert

Full section in one operation

SHAPE & SIZE OF TUNNELS

The size of the tunnel is determined by its utility. For

irrigation purpose, the tunnel is generally designed to

run full & if lining is of concrete, the velocity is taken

as 366 cm/sec. In case of road tunnels, it will depend

no. of traffic lanes & in case of railway tunnels, it

will depend on the no. of lines & type of gauge.

The shape of tunnel is determined by the material of

which the cross-section is built & material through

which the tunnel is bored.

MAINTENANCE OF RAILWAY

TUNNELS The slopes of portals at entry & exit should be

checked.

It should be seen whether the masonry has

crushed, cracked or deteriorated.

The track through the tunnel should be in line and

level.

The dimensions of tunnel should conform to original

dimensions.

The lining of tunnel should be examined & checked if

it is in a satisfactory condition.

PRESENTATION ON RAILWAY ENGINEERING

Railways were first introduced to India in 1853.

By 1947, the year of India's independence, there

were forty-two rail systems. In 1951 the systems

were nationalised as one unit, becoming one of

the largest networks in the world. Indian

Railways operates both long distance and

suburban rail systems.

• It is a branch of civil engineering concerned with the design,

construction, maintenance, and operation of railways.

• Railway engineering includes elements of civil, mechanical,

industrial, and electrical engineering.

• Railway engineers handle the design, construction, and operation of railroads

and mass transit systems that use a fixed guideway (such as light rail or even

monorails).

• Typical tasks would include determining horizontal and vertical alignment

design, station location and design, construction cost estimating, and

establishment of signaling & controlling system.

• Railroad engineers can also move into the specialized field of train

dispatching which focuses on train movement control.

The gauge of a railway track is defined as the clear minimum perpendicular distance between the inner faces of the two rails.

1. Broad Gauge(BG) 1676mm(5’6”)

2. Standard Gauge(SG) 1435mm

3. Metre Gauge(MG) 1000mm

4. Narrow Gauge(NG) 762mm(2’6”)

5. Light Gauge 610mm

• Coning of wheels – The distance between the inside edges ofwheel flanges is generally kept less than the gauge. Gap isabout 38 mm on Either side. Normally the tyre is absolutelyahead centre on the head of the rail, as the wheel is coned tokeep it in this central position automatically. These wheel areconed at a slope

• Theory of coning:- On a level track, as soon as the axle movestowards one rail, the diameter of the wheel tread over the railincreases, while It decreases over the other rail. This preventsto further movement And axle retreats back to its originalposition (with equal dia or both rails and equal pressure onboth rails).

Coning of Wheel on Level-track

The high carbon rolled steel sections, which are laidend-to-end, in two parallel lines over sleepers toprovide continuous and leveled surface for the trainsto move and for carrying axle loads of the rollingstock are called rails.

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Functions of the rails:

To provide continuous and level surface for the movement of trains with minimum friction with steel wheels of the rolling stock;

Provide strength, durability and lateral guidance to the track;

Transmit the axle loads to sleepers which transfer the same load to the underlying ballast and formation;

Bear the stresses developed due to heavy vertical loads, breaking forces and temperature variance.

Types of rails:

1. Double Headed Rails (DH Rails)

2. Bull Headed Rails (BH Rails)

3. Flat-footed Rails (FF Rails)

On Indian Railways the standard lengths are the following:

Length = 12.80 m. (42 ft.) for BG (say 13 m) and Length = 11.89 m. (39 ft.) for MG (say 12 m)

In certain places, head of rails are found to becorrugated rather than smooth and straight,when the vehicles pass over such rails, a roaringsound is created which is intense enough to beunpleasant.

Due to battering action of wheels over the end of the rails, therails get bent down and get deflected at the ends. These rails arecalled hogged rails.

Measures taken to rectify the hogged rails are:

1. Cropping

2. Replacing

3. Welding

4. Dehogging

Measures taken to rectify kinks in rails:

1. By correcting alignment at joints and at curved locations.

2. Proper packing of joints.

3. Proper maintenance of the track periodically in repect of cross levels, gauge, alignment, welding of worn out portions etc.

Damaged Rails

These are the rails which should be removed on account of their becoming unsafe for a railway track.

• Crushed Heads

• Square or Angular Break

• Split Heads

• Split Web

• Horizontal Fissures

• Transverse Fissures

• Flowing Metal in Heads

• Horizontal Cracks

• Supported Rail Joint• Suspended Rail Joint• Bridge Joint• Base Joint• Welded Rail Joint• Staggered or Broken Joint• Square or Even Joint• Compromise Joint• Insulated Joint• Expansion Joint`

(i) Sleepers move out of position thereby the rail gauge.

(ii) Position of points and crossings are disturbed.

(iii)Interlocking mechanism getsdisturbed.

• Pulling back of rails

• Provision of Anchors or Anticreepers.

• Use of steel sleepers.

Anticreeper

Sleepers

Sleepers are the transverse ties that are laid to support the rails. They transmit wheel load from the rails to the ballast.

(i) Wooden sleeper

(ii) Metal sleeperCast iron sleeper

Steel sleeper

(iii) Concrete sleeperReinforced concrete Sleeper (R.C.C)

Prestressed Concrete Sleeper .

• Hard wood such as, sal and teak

• Soft wood such as, chir and deodar

Sleeper density is the number of sleepers Perrail length. It is specified as (M+x) or (N+x),where M or N is the length of the rail in metersand x is a number that varies according tofactors such as axle load, speed, type & sectionof the rail etc.

It varies in India from M+4 to M+7 for maintracks.

• Bolts– Dog or Hook bolt– Fish bolt– Rag bolt– Fang nut and bolt

• Keys– Wooden key for C.I. Chair– M.S. key and steel trough

sleepers– Stuart’s key– Morgan key– Cotter and tie bars

• Fish plates

• Spikes

– Dog spikes

– Screw spikes

– Round spikes

– Standard spikes

– Elastic spikes

• Chairs

– Cast steel chairs

– Mild steel and Cast Iron Slide Chairs

• Blocks

– Heel blocks

– Distance blocks

– Crossing blocks

– Check blocks

• Plates

– Bearing Plates

– Saddle Plates

Ballast in railroad terminology is durable granular material placed between

the crosstie and the sub ballast to hold the track in line and grade.

The primary purposes of ballast are:

To provide structural support forthe track, holding it in good lineand surface

To distribute the load evenly to thesubballast and subgrade and thushelp to provide stability

Provide for drainage

SUBBALLAST SUBGRADE

BALLAST SECTION

• Broken Stone• Gravel or River Pebbles or Shingle• Ashes or Cinders• Sand• Mooram• Kankar• Brick Ballast• Blast Furnace Slag• Selected Earth

• For wooden sleepers

• For steel sleepers

= 5.1 cm

= 3.8 cm

• For under switches & crossings = 2.54 cm

• Points and crossings provide flexibility ofmovement by connecting one line to anotheraccording to requirements.

turnouts which necessarily retard• They also help for imposing restrictions over

themovements.

• From safety aspect, it is also important as pointsand crossings are weak kinks or points in thetrack and vehicles are susceptible to derailmentsat these places.

• It’s the simplest combination of points and crossings which enables one track either a branch line or a siding, to take off from another track.

• Parts of a turnout:– A pair of points or switches– A pair of stockrails– A Vee crossing– Two check rails– Four lead rails– Switch tie plate– Studs or stops– Bearing plates, slide chairs, stretcher bars etc.– For operating the points – rods, cranks, levers etc.– For locking system – locking box, lock bar, plunger bar etc.

CrossingsA crossing or a frog is a device which provides two flangewaysthrough which the wheels of the flanges may move, when tworails intersect each other at an angle.

• Turnouts• Symmetrical split• Three throw switch• Double turnout or Tandem• Diamond crossing• Cross overs• Single slip and double slip• Gauntlet track and ladder tracks• Temporary diversion• Triangle• Double junctions