Construction+Features+of+Bridges

=**Construction Features of Bridges**= //The following will detail the specific features and utilities that bridges utilize, and are to be composed of.//

A **Truss** is a structure comprised of a series of triangles connected at joints called nodes. There are 3 types of trusses: **Deck**, **Pony**, and **Through**. In a Deck Truss, traffic travels on top of the main structure, which is cross-based bottom of the bridge. In a Pony Truss, the traffic travels in between parallel superstructures which are not cross-braced at the top, rather above the bridge at either side. In a Through Truss, traffic travels through the superstructures which is cross-braced above and below the traffic.

Within simple deck and beam bridges, **Girders**, that which are typically composed of various metals or concrete, are used within the structures. Girders are used for support within the bridges and, without using haunches, girders are typically used in two styles: **Deck Style**, in which girders run parallel across the length of the bridge and **Pony Style**, in which the girders are above the deck and have a slight arch. **Haunches**, are located at the ends of bridges, and function much like an abutment, and having a slight arch at the end meeting the land. A way the load capacity of a bridge with girders can be increased is by utilizing the aforementioned haunches.

Simple supports that can be found in most bridges are the **Abutments**, **Piers**, and **Columns.** Abutments are the end supports that are located at either end of a bridge. They provide a basic reactonary force and are noticable on most bridges. Piers are the verticle supports that are at times located throughout the corse of bridges, which too function as reactionary forces, found on such bridges as suspension bridges, and extend far into the sky past the deck. Columns are a basic design structure, those being tall, slender, rigid, verticle bars, and can be found being used as components in the same fashon as girders, merely being vertical.

People use **Lamination** on wood for bridges. The material used is glued laminated timber, also called glulam, that is composed of several layers bonded together with durable, moisture-resistant adhesives. This material is called 'laminating stock' or lamstock for short. Pressure-treated glulam timbers or timbers manufactured from naturally durable wood species are well suited for creating bridges and waterfront structures. Wood’s ability to absorb impact forces created by traffic and its natural resistance to chemicals, such as those used for de-icing roadways, make it ideal for these installations. Glulam has been successfully used for pedestrian, forest, highway, and railway bridges. An example in North America of a glulam bridge is at Keystone Wye, South Dakota, constructed in 1966 - 1967. The Kingsway Pedestrian Bridge in Burnaby, British Columbia, Canada, is constructed of cast-in-place concrete for the support piers, structural steel and glulam for the arch, a post tensioned pre-cast concrete walking deck, and stainless steel support rods connecting the arch to the walking deck.

In a simple understanding, **Corrugation** can be mearly thought of the proccess of corrugating. The state of being corrugated i in a corrigated pattern, that patern looking like a series of alternate parallel folds. Corrugated materials can be placed in high stressed areas, such as underneath the deck, as ameans of strengthening that area. Corrugated materials in tiers ofbridges will typically be wood, or a metal like steel.



A model of a bridge with truss construction.


 * Truss** - A structure comprised of a series of triangles connected at joints called nodes.


 * Lamination** - The process of constructing laminate (a material consisting of 2 or more layers of material together).


 * Corrugation** - The process of corrugating (to shape into folds or parallel or alternating ridges or grooves).


 * Column** - A rigid, relativly slender, upright suport, comprised of relativly few pieces.


 * Girder** - A suport beam that is used in construction


 * Piers** - An upright suport for a bridge, acts as a reactionary force


 * Abutment** - The end suport for a bridge, which acts as a reactionary force.

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