Bridges

What are Bridges?

• 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

Characteristics of Bridges

Abutment

• • • 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.

Beam

• • • 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.

Bent

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

Bridge Bearing

• • • 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.

Counterweight

• • • 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.

Deck

• • • 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.

Elastomeric Bridge Bearing

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

Foundation

• • • 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.

Girder

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

Guard Rail

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

Pier

• • • 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.

Pile

• • • 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.

Side Plate

• • • 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.

Superstructure

• • • The superstructure is the part of the bridge that absorbs the live load.

Types of Bridges (Page Link)

Bridge Use Cases