Types of bridge and bridge components

Bridges are generally made of various types and materials and an essential part of transportation.

Bridge: It is mainly a structure which is built to stretch physical obstacles without closing the original way underneath like a body of water, valley or road etc. to make a passage over the hurdle.

There are lots of different designs from which each of them can be served for a distinct purpose and can be applied in different situations. The designs of the bridges differ as per the function of the bridge, the nature of the soil where the bridge has constructed and anchored, the material used to make it and the available funds for it.

There are mainly 4 types of bridges such as, 1) Bridges by Structure, 2) Fixed or Movable Bridges, 3) Types by Use and 4) types of Materials.

Bridges by Structure:

1. Arch bridges: The bridges use arch as a main structural element and also made with one or more articulations depended on the kind of load and stress forces endured. Ex: - “Old Bridge” in Mostar, “Bosnia and Herzegovina” and the “Hell Gate Bridge” in New York.

2. Beam bridges: They are very basic type of bridges which are supported by many beams of various shapes and sizes like inclined or V shaped. Ex: - “Lake Pontchartrain Causeway” in Southern Louisiana.

3. Truss bridges: They mainly use diagonal mesh of posts above the bridge and two most common designs are the King posts and queen posts.

4. Cantilever bridges: They are like the arch bridges in appearance but support their load through the diagonal bracing than vertical bracing and often use truss formation both in the below and the above the bridge. Ex: - “Queensboro Bridge” in New York City.

5. Tied arch bridges: Same appearance of the arch bridges but transfer weight of the bride and traffic load on the upper chord that is connected at the bottom cords in bridge foundation and these types of bridges are often called bowstring arches or bridges.

6. Suspension bridges: These kinds of bridges generally use ropes or cables from the vertical suspender for holding the weight of bridge deck and traffic. Ex: - “Golden Gate Bridge” in San Francisco.

7. Cable-stayed bridges: They use deck cables which are straightly connected to one or more vertical columns as cables generally connected to columns in two ways- harp design and fan design.

Fixed or movable types of bridges:

1. Fixed: Most of the bridges in this world are fixed and have no movable parts for providing higher clearance for river or sea transportation which flows below them. These bridges are mainly designed for staying in one place till their demolishing.
2. Temporary bridges: These bridges are made of modular basic objects which can be moved by medium or light machinery and used in military engineering or in circumstances as in time of fixing or repairing.
3. Moveable bridges: Powered by electricity and have moveable decks also.

Video Source: Sami Ullah Stanikzai

Types by use:

1. Car traffic: They are usually very common and have two or more than two lanes which are designed for carrying car and truck traffic of various depths.
2. Pedestrian bridges: They are generally found in the urban environments where car transportation way is through the soils of rough mountains, forests etc.
3. Double-decked bridges: They are naturally built to maintain as better as the traffic movement can be flowed across bodies of water or rough land. They often have large amount of car lanes and sometimes have the dedicated areas for train tracks.
4. Train bridges: Especially made for carrying one or more than one lanes of train tracks.
5. Pipelines: They can carry water, air, gas and communication cables in the water or remote lands.
6. Viaducts: They are old-fashioned structures which are created for carrying water in the prosperous areas to dry cities.
7. Commercial bridges: Modern bridges are now built as a decoration to the commercial buildings like restaurants and shops.

Types by materials: Natural materials like wood, stone, concrete and steel and some other advanced materials.

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Published By
Rajib Dey
www.constructioncost.co

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Ring 3.0 – A powerful software for bridge analysis and masonry design

LimitState Ltd has developed RING, a powerful construction program for bridge analysis and masonry design.

The most updated version is RING 3.0. The newest version can be used for analyzing masonry arch bridges. The software is mostly suitable for structural engineers.

The software provides the following advantages :-

• Analyze single or multi-span bridges without having fixed upper limit on the permissible number of spans
• Automatically determine the critical failure mode although:
o only a single span is associated
o sliding is involved
modelling multi-ring arch bridges
• Determine and resolve numerous multiple load cases
• Automatically find out 'passive' pressures - analyze deep and multi-span arch issues with ease
• Model the presence of arch backing material
• User-friendly wizard system facilitate simple and rapid model definition
• Modern, uncomplicated interface supported with an collaborating modeling environment

Extensive library comprises of standard road and rail vehicles
• Property editor facilitates fast querying and adjustment of model properties
• 3D graphical output for superior perception
• Automatic report creation

• User-accountable arch and backfill profiles
• User-accountable separate block weights, masonry strength, mortar loss etc.

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Published By

Rajib Dey

www.constructioncost.co

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Variations among Warren Truss, Howe Truss and Pratt Truss

In engineering, a truss belongs to a structure that contains two-force members only. The members are arranged in order that the truss can act like a single object. The truss facilitates the structures to transmit weight to its foundations and anchors securely.

The members of truss are only dependent on axial compression and tension and not on bending moment.

The truss employs a web of triangles which are attached in order that pressure and tension are used to the points of the corners of every triangle to make them stable for providing support to structure. By associating a wide array of trusses collectively, significant amount of weight can be transmitted securely to load-bearing beams, wall or to the ground directly.

Generally, the trusses are categories as Warren truss, Pratt truss and Howe truss.

Warren truss is supported with a set of isosceles triangles or equilateral triangles. The verticals are included with Warren Truss with the purpose of raising the span length of the truss bridge.

Pratt truss is defined by its diagonal members (excluding the end diagonals) which are sloped down towards the middle of the bridge span. This type of structural arrangement is based on when external loads tension is caused in diagonal members whereas the vertical members manage compressive forces. Therefore, thinner and lighter steel or iron is applied as materials for diagonal members with the purpose of building up a more well-organized structure.

The design of Howe truss is contrary to that of Pratt truss in which the diagonal members are sloped in the direction contradictory to that of Pratt truss (i.e. slanting away from the middle of bridge span) and as such compressive forces are formed in diagonal members. Therefore, it is not cost-effective to employ steel members to deal with compressive force.

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Published By

Rajib Dey

www.constructioncost.co

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How bridge works to sustain various loads

This construction article focuses on uses and types of bridges.

How bridges balance forces
Things are moved through forces, but they also retain them stagnant. A bridge remains stand steels as all the forces operating on it are correctly in balance. In a nutshell, bridge designers can be described as force balancers.

A bridge extents over a river, valley, sea, or road. There is no direct support under the enormous deck (the primary horizontal platform) of a bridge. If the bridge is lengthier, it becomes heavy and bears lots of weight. So, the chance for collapsing is increased. Bridges can sometime collapse, but most sustain securely for a prolonged period as it cautiously balance two primary types of forces known as compression (a pushing or compressing force, operating internal) and tension (a pulling or stretching force, operating external), by dispersing the load toward abutments (the supports at each side) and piers (one or more supports in the middle). There exist different types of bridges, substantially all of them function by balancing compressive forces in some areas with tensile forces somewhere else, so there does not exist universal force to induce motion and provide damage.

Carrying loads
At the time of unloading, a bridge has to provide support to its own weight (the dead load), therefore the tension and compression in its structure become really static forces (ones that don't give rise to movement) that is adjusted slightly from hour to hour or day to day. Though, by characterization bridges bear fluctuating amounts of weight (the live load) from things like railroad trains, cars, or people, which can significantly raise the ordinary tensile or compressive forces. Rail bridges, as for instance, bend and flex each time when an overweight train passes over them and then "relax" over again once the load has elapsed.

To read the complete article, go through the following link.
www.explainthatstuff.com

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Published By

Rajib Dey

www.constructioncost.co

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