Difference between Bridge and Flyover

The difference between Bridge and Flyover is based on the purpose of its usage and the location where it is built.

Bridges

• Bridges are built to connect two points separated by a naturally occurring region like valley, river, sea or any other water bodies, etc.
• They are usually lengthy depending upon the width of the valley or river.
• Construction over river is tedious since foundation has to be carried out on the river bed.
• Bridges are usually built for trains, buses and cars.
• 
  

Flyovers

• It is a structure which joints two or more points which are separated by an accessible route/s or a man made structure to cut the traffic for faster mode of travelling.
• They are usually made over road junctions, roads, streets, etc.
• The name itself suggests that you are flying over a traffic zone.
• They are usually built for road vehicles.

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Components of flexible pavement road construction

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POINTS TO REMEMBER FOR CIVIL SITE ENGINEERS

Following are few general points to remember for civil site engineers to make the construction work easier while maintaining quality of construction.

• Lapping is not allowed for the bars having diameters more than 36 mm.
• Chair spacing maximum spacing is 1.00 m (or) 1 No per 1m2.
• For dowels rod minimum of 12 mm diameter should be used.
• Chairs minimum of 12 mm diameter bars to be used.
• Longitudinal reinforcement not less than 0.8% and more than 6% of gross C/S.
• Minimum bars for square column is 4 No’s and 6 No’s for circular column.
• Main bars in the slabs shall not be less than 8 mm (HYSD) or 10 mm (Plain bars) and the distributors not less than 8 mm and not more than 1/8 of slab thickness.
• Minimum thickness of slab is 125 mm.
• Dimension tolerance for cubes + 2 mm.
• Free fall of concrete is allowed maximum to 1.50m.
• Lap slices not be used for bar larger than 36 mm.
• Water absorption of bricks should not be more than 15 %.
• PH value of the water should not be less than 6.
• Compressive strength of Bricks is 3.5 N / mm2.
• In steel reinforcement binding wire required is 8 kg per MT.
• In soil filling as per IS code, 3 samples should be taken for core cutting test for every 100m2.

Density of Materials:

Material	Density
Bricks	1600 – 1920 kg/m3
Concrete block	1920 kg/ m3
Reinforced concrete	2310 – 2700 kg/ m3

Curing time of RCC Members for different types of cement:

Super Sulphate cement: 7 days

Ordinary Portland cement OPC: 10 days

Minerals & Admixture added cement: 14 days

De-Shuttering time of different RCC Members

RCC Member	De-shuttering time
For columns, walls, vertical form works	16-24 hrs.
Soffit formwork to slabs	3 days (props to be refixed after removal)
Soffit to beams props	7 days (props to refixed after removal)
Beams spanning upto 4.5m	7 days
Beams spanning over 4.5m	14 days
Arches spanning up to 6m	14 days
Arches spanning over 6m	21 days

Cube samples required for different quantity of concrete:

Quantity of Concrete	No. of cubes required
1 – 5 m3	1 No’s
6 0 15 m3	2 No’s
16 – 30 m3	3 No’s
31 – 50 m3	4 No’s
Above 50 m3	4 + 1 No’s of addition of each 50 m3

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Rollers

Rollers are the construction equipment used for the compaction of soil, gravel, sand, crushed stone layers, etc.  Roller working principle is based on vibration, impact loading, kneading and by applying direct pressure on the respective layer. The four most commonly used rollers are;

1. Vibratory Roller
2. Tamping roller/ sheep foot rolle
3. Smooth wheel rollers
4. Pneumatic tired roller

VIBRATORY ROLLER

Vibratory type rollers have two smooth wheels/ drums plus the vibrators. One is fixed at the front and the other one is on the rear side of vibratory roller. Both wheels/drums are of the same diameter, length and also of same weight. Vibratory roller covers the full area under wheel. To make vibratory roller more efficient, vibrators are also fixed with smooth wheel rollers. Vibration of vibrators arrange the particles by first disturbing even the arranged ones. On the other hand weight of wheels exerts direct pressure on the layer. Vibrators are turned off during the reversed motion of roller. In that time only static weight directly acts on the soil layer.

Vibration is to reduce the air voids and to cause densification of granular soils. During vibration of soil layer,  rearrangement of particles occurs due to deformation of the granular soil because of oscillation of the roller in a cycle.

Vibratory Roller

SHEEP FOOT ROLLER/ TAMPING ROLLER

Sheep foot roller also named tamping roller. Front steel drum of sheep foot roller consists of many rectangular shaped boots of equal sizes fixed in a hexagonal pattern. Coverage area of sheep foot roller is less i.e., about 8- 12% because of the boots on drums. Sheep foot roller done compaction by static weight and kneading of respective layer. This makes tamping roller better suited for clay soils. Contact pressure of sheep foot roller varies from 1200- 7000Kpa.

Sheep Foot Roller

Tamping foot roller consists of four wheels and on each wheel kneading boots/feet are fixed. Tamping roller has more coverage area i.e., about 40- 50%. Contact pressure of tamping roller varies from 1400 – 8500KPa. It is best dedicated for fine grained soils.

Tamping Roller differs from sheep foot roller by its wheel type.

SMOOTH WHEEL ROLLER

Smooth wheel roller and vibratory rollers are the same. Both have the same characteristics. Only the difference in both is vibratory equipment. Smooth wheel roller has no vibrator attached with the drum. This makes smooth wheel roller best suited for rolling of weaker aggregates, proof rolling of subgrades and in compacting asphalt pavements. Compaction of clay or sand is not a good choice to done with smooth wheel roller. This is so, because there are many empty voids in clay soil and sand, which cannot be minimized without vibrators.

Smooth wheel roller

PNEUMATIC TIRED ROLLER

Pneumatic tired roller has a number of rubber tires at the front and at the rear end.  Empty spaces left in between the two tires that make 80% coverage area under the wheels. Pneumatic roller has the ability to exert contact pressure ranges from 500 – 700Kpa. Pneumatic tired roller can be used for highways, construction of dams and for both fine grained and non-cohesive soils. It is also used for smoothening of finishing bitumen layer on highways, roads, streets etc.

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10 Tallest Bridges In The World== >

1. Millau Viaduct, France – 343 metres (1,125 ft) tall. Opened in 2004, this 4 lanesbridge is a cable-stayed bridge that spans the valley of the River Tarn near Millau in southern France. The bridge has 7 piers of different heights. The second one is the tallest with a height of 244.96 m (803 ft 8 in) – making it the tallest structure in France, taller than the Eiffel Tower!

2. Russky Bridge, Russia – 320.9 metres (1,053 ft) tall. Located in Vladivostok, the bridge was completed in 2012. It connects the mainland part of the city with Russky Island

3. Sutong Bridge, China – 306 metres (1,004 ft) tall. Opened in 2008, this bridge spans the Yangtze River between Nantong and Changshu

4. Akashi-Kaikyo Bridge, Japan – 298.3 metres (979 ft) tall. This beautiful suspension bridge was opened in 1998. It links the city of Kobe on the mainland of Honshu to Iwaya on Awaji Island. It is the tallest suspension bridge in the world

5. Stonecutters Bridge, Hong Kong – 298 metres (978 ft) tall. A high level cable-stayed bridge which spans the Rambler Channel in Hong Kong, connecting Nam Wan Kok, Tsing Yi island and Stonecutters Island. The bridge deck was completed and opened to the public in 2009

6. Yi Sun-sin Bridge, South Korea – 270 metres (890 ft) tall. Except of being the 6th tallest bridge in the world, it’s also the second tallest suspension bridge in the world and the fourth longest suspension bridge in the world

7. Jingyue Bridge, China – 265 metres (869 ft) tall. This cable-stayed bridge in Jianli County was opened in 2010 and crosses the Yangtze River

8. Great Belt East Bridge, Denmark – 254 metres (833 ft) tall. Opened in 1998, this bridgeruns between the Danish islands of Zealand and Funen. It is the third tallest bridge in Europe

9. Zhongxian Huyu Expressway Bridge, China – 247.5 metres (812 ft) tall. Completed in 2010, this bridge crosses the Yangtze River in Zhong County

10. Jiujiang Fuyin Expressway Bridge, China – 244.3 metres (802 ft) tall. A Cable-stayed bridge under construction and should be completed by the end of 2013. With a main span of 818 m (2,684 ft) it will become one of the longest cable-stayed bridges in the world upon its completion

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10 Highest Bridges In The World = =>>

1. Sidu River Bridge, China – Height of 496 m (1,627 ft). This 1,222 m (4,009 ft) long suspension bridge is the world’s highest bridge since 2009. Located in the Hubei Province, it  crosses the valley of the Sidu River

2. Baluarte Bridge, Mexico – Height of 403 m (1,322 ft). A cable-stayed bridge, located along the Durango–Mazatlán highway. The bridge has a total length of 1,124 m (3,688 ft), the second-highest bridge overall

3. Baling River Bridge, China – Height of 370 m (1,210 ft). A suspension bridge in Guizhou Province. The bridge spans over the Baling River Valley. The bridge has a total length of 2,237 m (7,339 ft)

4. Beipanjiang River 2003 Bridge, China – Height of 366 m (1,201 ft). A suspension bridge in Guizhou Province. The bridge has a span width of 388 metres. Between 2003 and 2005, it was the world’s highest bridge

5. Aizhai Bridge, China – Height of 350 m (1,150 ft). A suspension bridge in Hunan, China. It is the world’s highest and longest tunnel-to-tunnel bridge

6. Beipanjiang River 2009 Bridge, China – Height of 318 m (1,043 ft). A suspension bridge in Guizhou Province. It crosses the Beipan River. It was opened to the public in 2009, just 6 years after another (and higher) bridge crossing the same river was opened (see number 4 in this list)

7. Liuguanghe Bridge, China – Height of 297 m (974 ft). A beam bridge in Guizhou, China. It held the record for world’s highest bridge between 2001 and 2003. It is still the highest beam bridge in the world

8. Zhijinghe River Bridge, China – Height of 294 m (965 ft). The highest arch bridge in the world. The bridge crosses the valley of the Zhijinghe River and is opened to the public since 2009

9. Royal Gorge Bridge, Colorado, United States – Height of 291 m (955 ft). The Royal Gorge Bridge is a tourist attraction within a theme park. The bridge deck crosses the Royal Gorge 955 feet (291 m) above the Arkansas River, and held the record of highest bridge in the world from 1929 until 2001. The bridge is 1,260 feet (384 m) long It is the highest in the United States

10. Beipanjiang River Railway Bridge, China – Height of 275 m (902 ft). The world’s highest railway bridge. The bridge spans a deep canyon on the Beipan River in Guizhou province. This is the third bridge within this list spanning over the Beipan river

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==>> RESEARCH ON TRANSPORTATION ENGINEERING==>>

A Goal-Oriented Method for Urban transport Strategy Development for Indian
Metropolitan Areas==>>


Most of the Indian cities today are typically characterized by high-density urban areas, absence of proper control on land use, lack of proper roads and parking facilities, poor public transport, lack of road user discipline etc. The resultant effects are; increased traffic congestion and transport-borne pollution, heavy fuel consumption, poor level of service to the commuter etc.


So far, only isolated approaches to solve single problems are used in most of the Indian cities. An integrated approach which considers different combinations of measures (in infrastructure and traffic management) and their joint impact on the different goal areas (mobility, safety, environment, economy etc.) are fairly not used. Approaches traditionally adopted for developing urban transport strategies for Indian cities are bottom-up in nature and focus largely on infrastructure expansion and do not adequately consider traffic and demand management measures. Hence, the study will focus on a goal-oriented and cooperative method for establishing comprehensive urban transport strategies for Indian Metropolitan Areas


Development of a Simultaneous Approach for Integrated Mass Transit Planning==>>

The objective of this project would be to develop a simultaneous and iterative approach for
planning an effective and efficient integrated urban mass transit system for any city which
has a potential demand for a new rail-based mass transit system besides the street transit
system and any existing rail-based system

Air Travel Demand Modeling for Indian Cities==>>


This would involve work on developing a model for forecasting air travel demand for Indian cities. Unfortunately in India, there has not been any scientific approach used for forecasting the air travel demand. International Civil Aviation Organization (ICAO) forecasts predict worldwide growth in air traffic at 5% a year or doubling in the volume of traffic once in 14 years. Similar trend has been adopted in India for forecasting the air travel demand. Airport Authority of India (AAI) has considered a growth rate of 7% for the period 2007 to 2011. AAI has extended this growth rate for the period 2012-2017, and is taken as 6%. Rapid economic development that has been seen in the last one decade resulted in unpredicted growth in air traffic. A growth rate of 24 % has been observed in over all domestic air traffic for the year 2004-2005. From the observations it can be concluded that there has not been much work done in the past regarding air traffic demand forecasting in India. Trends observed in international air traffic are currently being used for forecasting air traffic in Indian skies. Hence, there is a clear requirement for taking up this study to develop a proper air-travel demand forecasting model for Indian cities.


Development of a Web-based Transit Passenger Information System (PIS) Design==>>

This study includes work on a web-based multi-objective and Generalized Cost (GC) based.Passenger Information System (PIS) design for multi-modal transit system that integrates geo-informatics, network analysis, user-interfacing and database management. The GC approach for trip planning is especially important in Indian scenario, where the various modes of transport are generally not harmonized, and the transfer time from one mode to another may be very large. It also imitates the natural tendency of public transport users to attach differential importance to various legs of a trip (walking, waiting, travel time etc.),
while planning for it...

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==>>CLASSIFICATION OF SOILS FOR HIGHWAY USE<<==

                    ==>>CLASSIFICATION OF SOILS FOR HIGHWAY USE<<==

==>>

Soil classification is a method by which soils are systematically categorized according to their probable engineering characteristics. It therefore serves as a means of identifying suitable subbase materials and predicting the probable behavior of a soil when used as subgrade material.

The classification of a given soil is determined by conducting relatively simple tests on disturbed samples of the soil; the results are then correlated with field experience. Note, however, that although the engineering properties of a given soil to be used in highway construction can be predicted reliably from its classification, this should not be regarded as a substitute for the detailed investigation of the soil properties.

Classifying the soil should be considered as a means of obtaining a general idea of how the soil will behave if used as a subgrade or subbase material.

The most commonly used classification system for highway purposes is the American Association of State Highway and Transportation Officials (AASHTO) Classification System. The Unified Soil Classification System (USCS) also is used to a lesser extent. A slightly modified version of the USCS is used fairly extensively in the United Kingdom.

==>>AASHTO Soil Classification System==>>


The AASHTO Classification System is based on the Public Roads Classification System that was developed from the results of extensive research conducted by theBureau of Public Roads, now known as the Federal Highway Administration. Several revisions have been made to the system since it was first published. The system has been described by AASHTO as a means for determining the relative quality of soils for use in embankments, subgrades, subbases, and bases.

==>>Unified Soil Classification System (USCS)==>>


The original USCS system was developed during World War II for use in airfield construction. That system has been modified several times to obtain the current version which also can be applied to other types of construction such as dams and foundations. The fundamental premise used in the USCS system is that the engineering properties of any coarse-grained soil depend on its particle size distribution,whereas those for a fine-grained soil depend on its plasticity. Thus, the systemclassifies coarse-grained soils on the basis of grain size characteristics and fine-grained soils according to plasticity characteristics.


<<==

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==>>STEPS IN FUNCTIONALLY CLASSIFYING RURAL, URBAN AND URBANIZED AREA ROADWAYS<<==

==>>STEPS IN FUNCTIONALLY CLASSIFYING RURAL, URBAN AND
URBANIZED AREA ROADWAYS<<==

The Functional Classification flowchart,in whichfunctional classification development is recommended. This flow of activities logically takes you through the coordination process and the order of events required to obtain FHWA functional classification approval.

Using the new approved urban area boundary map:
1. Prepare a map showing the road network and the existing federal functional
classification superimposed over the new approved boundary map

2. Add land service characteristics, such as major traffic generators and land use
patterns. Current DOQQs are a good resource if available for your area.

3. Reclassify the functional classification for highway and streets where land service
characteristics have changed. NOTE* The revised functional classification will be
coded, as proposed. This will be a new characteristic.
DO NOT change the existing functional classification characteristic.

When reclassifying roads, remember to include logical system continuity
considerations. Select principal arterial systems first, followed by minor arterials,
then collectors and locals.

• Perform a preliminary classification of the total arterial system considering the list below Evaluate service to urban activity centers Consider system continuity .Determine land use considerations
Evaluate spacing between routes and the spatial distribution of activities to be served Average trip length
Traffic volumes (AADT) Access control Vehicle miles of travel and system mileage

• Classify the final arterial system breaking it into the principal and minor arterialstreet system By
service to urban activity centers
• Business districts
• Air, rail, bus, and truck freight terminals
• Regional retail shopping centers
• Large colleges, hospital complexes, military bases, and other
institutional facilities

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==>>Sub Surface Highway Drainage<<==

==>>Sub Surface Highway Drainage<<==

• Subgrade may be damaged by sub soil water.
• Sub soil water as free water, when water table is high or it may come up by capillary action to the subgrade when water table is low.
• Subgrade should be of self draining material so that it may pass off the percolation water that comes to it to remain dry and stable.
• But if subgrade is of soft and retentive soil, or there are underground dprings bringing free water to the subgrade fro that reason subsurface drains should be constructed about 1 ½’ to 2’ below the formation level to carry away water from the subgrade and thus keep it dry. ( in easily drainable soil water can be lowered by deep or open side drains, it also takes rain water.
• Cross-drains may be in the form of trapezoidal trenches filled with selected rubble called rubbled drains or trench drains.
• Depth is not much and the discharge is small.
• The pipes are surrounded by filler material and the remaining of the cross trench is filled with graded rubble,  the bigger size rubble being nearer to the pipe. Water of wet subgrade passes through the open joint of pipes and enter the lateral drain which discharge into the longitudinal drain pipe in the two longitudinal side trenches.
• Longitudinal drain carry water to the nearby stream.
• Cross-drains, staggered in herring bone fashion.
• Spacing of lateral drains is less in impermeable soil and more in permeable soil.

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==>>Costs of Highways==>>

                            

                                                   ==>>Determining Relevant Costs:              

           ==>>

            The total cost for improvements to a highway system or segment includes engineering and design, expenditures for planning, the outlay for acquiring rights of way, and the costs of constructing roadway, structures, and pavements. Selection of the cost items to be included in and excluded from specific economy studies requires straight and careful thinking. A detailed discussion is beyond the scope of this book. However, four of the most important considerations are as follows:

1.      In general, allocated costs, used for accounting purposes, should be omitted from economy studies. To illustrate, a given percentage may be added to estimated project costs for administration, planning, and engineering overhead. These costs probably will be incurred whether or not a specific project is undertaken; if so, they are not relevant in comparisons between possible courses of action. Stated differently, only the added or incremental costs are relevant.

2.      Expenditures made before the time of the economy study should not be considered. These are called sunk costs, in that they cannot be recovered by any present or future action. For example: the roadway and pavement of an existing road may be in good condition and have a substantial “book value” in the records of the highway agency. Nevertheless, if one alternatives in the economy study. Again, it would be improper to include costs incurred earlier for preliminary planning and design.

3.      All relevant costs must be included and all irrelevant charges excluded. In this regard, as mentioned earlier, transferred costs may be particularly trouble some. Assume, for example, that one of several plans for a proposed highway improvement requires a private utility company to move its facilities at its own expense. From a budgetary standpoint this cost is not chargeable against the project from a public works economy-study standpoint; however it is a proper charge. Economic resources are consumed. Even though paid from private rather than public funds.

4.      In certain types of economy studies. It is proper to make an allowance for the salvage value of a machine or structure at the end of its estimated useful life. As a general rule, salvage value should be neglected in economic studies for highways. It is conjectural at best to assume that an investment in a highway will have great worth 20, 30, or 40 yr in the future. One exception might be to assign salvage value to the land occupied by the road. Even in this situation only the raw value of the land in its predicted future use, after deducting the cost of converting it to that use, would be included. Other costs associated with acquiring the land in the first place, such as legal expenses and the cost of cleaning it of buildings cannot be recovered and would not be a part of the salvage value.

Proposed highway improvements often will bring changes in annual maintenance and operating costs. For present conditions, data for these should available from the cost records of the highway agency. Estimates of these costs for the proposed improvements must be projected. Here again, only the relevant costs are to be sure that only true cost differences are reflected.

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