Unit-5

Bridge Engineering

Q1)          What is a Bridge, its main parts & types of Bridges?

Ans 1)

The bridge, a connecting structure, creates bonding between different disconnected parts of a country, two banks of the ocean or parts of two countries. A bridge is a structural marvel which is generally used to pass any type of obstruction that can slow the life of people. From the very beginning, engineers have invented bridge structure which can use to overcome the natural obstacles.

Main parts of a Bridge

• Deck
• Abutment
• Pile
• Pier
• Girder
• Rail Track

Types of Bridges

• Truss Bridge
• Arch Bridges
• Suspension Bridges
• Cable-Stayed Bridges
• Slab Bridges
• Box Girder Bridges

Q2) Explain an Arch Bridge and its different types?

Ans 2)

An arch is described as flexuous support spanning the gap and serving as a support for the loads on top of the opening. This definition omits an outline of what variety of structural component, an instant, and axial force component, makes up the arch.

Arch bridges are one amongst the oldest sorts of bridges and have nice natural strength. They were originally designed of stone or brick however currently are designed of ferroconcrete or steel. The introduction of those new materials permits arch bridges to be longer with lower spans.

Types of Arch Bridges

• Deck Arch Bridge
• Through Arch Bridge
• Moment Tied Arch
• Fixed‐Fixed Concrete Arch
• Pinned‐Pinned Concrete Arch-
• Bowstring Arch
• Moment Tied Arch
• Aqueducts and canal viaducts 
• Corbel arch bridge

Q3)  What are the advantages & disadvantages of Arch Bridges?

Ans 4)

Advantages

• Provides a better level of resistance
• Design is good in terms of pressure
• Designed from virtually anything
• Structurally sound
• Comes with no distortion
• Becomes stronger because it works
• Offers economic advantages

Disadvantages

• Restricted span
• Constraints on the location
• Needs additional maintenance
• Needs additional support
• Will take long to build
• Pricey to build

Q4) Explain a Suspension Bridge & its type?

Ans 4)

A suspension bridge is one wherever several cables are set up across two or many towers that support the bulk of the bridge weight and force. The cables run from the tower to the anchorages.

Suspension bridges are robust and might span long distances. They are high-priced as a result of they take an extended time to create and need an oversized quantity of the fabric. They are sometimes found across harbors with tons of boat traffic. The first parts of a bridge are a try of main cables stretching over two towers and hooked up at every finish to an anchor. Smaller cables hooked up to the most cables support the route.

The most components of a span are the towers, anchors, main cables, suspension cables, and therefore the route. A span is extremely completely different from arch bridges, although there will be an arch in an exceeding span. Altogether suspension bridges, the route hangs from huge steel cables that are draped over two towers and secured into solid concrete blocks, referred to as anchorages, on each end of the bridge. Cars cut down on the route, however, because of the route is suspended, the cables transfer the load into compression within the two towers. The two towers support the bridge's weight.

Types

• Simple Suspension Bridge
• Under-Spanned Suspension Bridge
• Stressed Ribbon Bridge
• Self Anchored Suspension Bridge

Q5) What are the advantages & disadvantages of Suspension Bridges?

Ans 5)

Advantages

• Economic Advantage: The realm spanned by a bridge is extremely long in proportion to the number of materials needed to construct bridges.
• Height Advantage: Built over waterways, suspension bridges are engineered high, permitting the passage of tall ships unrestrained by the bridge.
• Construction Advantage: Throughout construction, temporary central supports do not have to be compelled to be engineered, and access to the development is not needed from below. This implies busy roadways and waterways do not have to be compelled to be discontinuous.

Disadvantages

• Heavy Loads: Flexibility also becomes an obstacle once significant, focused loads are concerned. Suspension bridges do not seem to be usually used for regional rail crossings that carry most weight loads that add dangerous stress to the structure.

• Loss of Income: Despite the low prices of constructing suspension bridges and therefore the job opportunities they provide, the length of your time required to complete building these bridges are long. Taking a longer time may be the results of the loss of income that may be full of the economy site.

• Foundation pitfalls: Once inbuilt soft ground, suspension bridges need in-depth and high-ticket foundation work to combat the results of the significant load on foundation towers.

• Load Limitations: Another pitfall of a suspension bridge is that the material used that are the cables. These cables have limitations once it involves bearing the burden of masses. Though it will enable a minimum weight with relevance vehicles passing through, an excessive amount of weight will cause the breaking of cables.

• Restricted Applications: Suspension bridges, despite their cost-effectiveness in construction and adaptability once it involves site location, have limitations once it involves its use. This can be as a result of they will be destroyed by sturdy winds and not sturdy enough to carry limitless weight, careful thought ought to be taken before construction.

Q6) What is a Beam Bridge? Classify the different types?

Ans 6)

A bridge could be a construction that's designed to hide a road, valley, water body, or alternative natural obstacles to providing a route over the barrier. Many bridge styles are used that depend on the soil conditions of the location for bridge construction. Among them, beam bridges are the oldest and simplest bridge style consisting of vertical piers and horizontal beams - e.g. Simply an easy plank or stone block. They comprise vertical piers and horizontal beams. A beam bridge’s strength depends on the strength of the route and multiplies by adding extra piers. Whereas beam bridges are quite long, the span, or distance between adjacent piers, is typically small.

Types

Beam Bridge can be classified into many types based on four main criteria. They are as follows:

1. Based on geometry
   • Straight beam
   • Curved beam
   • Tapered beam 
2. Based on the shape of the cross-section:
   • I-beam
   • T-beam 
   • C-beam 
3. Based on equilibrium conditions:
   • Statically determinate beam 
   • Statically indeterminate beam 
4. Based on the type of support:
   • Simply supported beam
   • Cantilever beam
   • Overhanging beam
   • Continuous beam
   • Fixed beam

Q7) What are the different advantages & disadvantages of Beam Bridges?

Ans 7)

Advantages

There are situations when the beam bridge has more advantages than other types of bridges. Followings are the major advantages of beam bridges:

• A beam rests simply on the supports.
• The effects of thermal expansion and movements of the ground are easily sustained.
• A beam could also be engineered removed from the ultimate position and raised fleetly into place with least disruption of traffic or navigation.
• Beam bridges are easy to construct.
• In comparison to other bridge types, beam bridges are less costly.
• Mostly used widely in urban and rural zones.

Disadvantages

Followings are the disadvantages of the beam bridges:

• Beam Bridge contains forces, which are much larger than the load, and it needs to be relatively massive.
• Beam Bridges have a limited span and do not allow large boats or vehicles to pass underneath.
• Mostly heavy boat traffic or large ships cannot pass underneath.
• People may not find the design of beam bridges spectacular.

Q8)  What are the Economic & Political Impacts of Bridges?

Ans 8)

Economic Impacts

• Bridges are used for shipping raw materials and goods. You can move them to different factories, warehouses, suppliers, distributors, stores and many more. Bridges can be used for travel purposes too. Purchasing goods and services are another economical impact of bridges.
• Wages earned after a bridge is built goes to the development arena. It easily pays off more than investment. It helps a nation’s economy to grow higher than ever. Maintenance workers get facilities in this case. They can buy things to invest in local business.
• Bridges build an excellent relationship between where there is good money there are authentic goods. One place supplies goods and other pays off well for that stuff. Here is an exchange of power. This way a bond is built between workers and investors. Raw materials are transferred to industrial areas in the easiest way.
• The proper drainage system will make sure there is no clogged up path during monsoon. It will ensure less traffic jam and less accident.
• When big transports can move faster, goods will be delivered sooner. So less rotten materials will be delivered. Frozen stuff can be delivered sooner and it will keep its freshness intact.

Political Impacts

• Building safe and long lasting bridges is exemplary for both own and outside people. It is recognition for both the nation and the world. This is an example of development towards the outward world. As a good example is set to a good relationship is brought.
• Adding footpath on bridges can add new dimensions, it often helps them to enjoy the beautiful site. It becomes a natural heritage site for people coming from outside too.
• Small trees can be planted to enhance the beauty of the bridges, colorful lights will make sure there happens no occurrence during night time.
• Bridges connect communities of distant places. Bridges bring diversity. Good quality is maintained. Both diversity and quality bring new joy. Raw materials contribute to new inventions. This way one good relation is built with consumer and government.
• The government collects sales taxes through the income coming from bridges. That goes to the overall development or any local business help.
• Firms need efficient workers. Contractors bring more people from different communities. A contract has to first bid and then win with the lowest quotation. It needs an experienced mind.

Q9)  What is a Culvert?

Ans 9)

Culvert is a tunnel carrying a stream under a road or railway. A culvert may act as a bridge for traffic to pass on it. They are typically found in a natural flow of water and serve the purpose of a bridge or a current flow controller.

Culvert is provided under roads and highways for a crossing of water, as road embankment cannot be allowed to obstruct the water flow. The culvert is ideally suited for a road to limit water flow in a controlled way. There are some common types of culvert such as pipe, box, and arch culvert. The culvert type is based on hydraulic, water surface elevation, and roadway height and other conditions.

Q10) What are the materials for Culvert construction?

Ans 10)

Surrounded by soil, a culvert may be made from a pipe, reinforced concrete or other material. Materials for culvert construction are based on the following materials present below which improves the quality of it.

The selection of material depends on:

• Structure strength
• Hydraulic efficiency
• Installation, local construction practices
• Durability
• Cost

The main materials for culvert construction are

• Steel- Structural Steel Plate (SSP) & Corrugated Steel Pipe
• Aluminum Pipes
• Concrete
• High-density Polyethylene (HDPE)