Bridges

Table of Contents

Golden Gate Bridge [1]

A bridge is a structural component built to span a physical obstacle, such as water, a valley, or road.
The purpose of a bridge it to allow passage over the obstacle

Components of a Bridge [2]

- - Abutments are the elements at the end of a bridge.
  - They absorb the forces exerted on the bridge and act as a retaining wall that prevent the earth from moving under the bridge.

Diagram of an Abutment [3]	Abutment [4]

- - A beam is a structural component on a bridge which resists loads applied to it and responding with reaction forces at the support points of the beam.

Beam [5]

- - A bent is a structural element which is used to construct a trestle, and is a key support in many bridges.

Bent [6]

- - A bridge bearing is the resting surface between the piers and deck of a bridge.
  - This allows for controlled movement due to thermal expansion or contraction as well as any seismic shaking that may occur.
  - Different bearings allow for back and forth motion while others can allow twisting as well.

Bearing [7]

- - A counterweight is used on bridges that have a bridge lift system
  - A counterweight is a weight that stabilizes and provides balance for this bridge lift system.

Counterweight [8]

- - The deck of a bridge is also known as the roadway. It allows for vehicles and pedestrians to travel across the bridge.
  - Decks are usually constructed of either concrete, steel, or wood. They are then covered with asphalt or concrete.

Deck [9]

- - This type of bearing is designed to compress under a vertical load, allow for horizontal rotation and lateral shear movement.

Elastomeric Bearing [10]

- - The foundation is the element that connects the bridge to the earth and allows for loads to be transferred from the bridge to the ground.

Foundation [11]

- - A girder is the main horizontal beam on a bridge. It is used to support the smaller beams located throughout the bridge.

Girder [12]

- - A guard rail is the system of rails on the outside of bridges to prevent vehicles or pedestrians from falling off the bridge.

Guard Rail [13]

- - A pier is utilized in bridges that span a body of water.
  - The pier is the structure that sits in a body of water to support the bridge.
  - Piers are spread out under a bridge to allow water to flow through so that pressure is not built up against the piers.

Pier [14]

- - A pile is a vertical support that is used to hold up a bridge.
  - A pile is hammered down to the hard sub layer of earth and is constructed of wood, concrete, or steel.

Pile [15]

- - A side plate is a linear bearing that is part of the expansion joint of a bridge.
  - One plate is fixed while the other is able to slide to accommodate expansion and contraction.