Bearings and Bearings and Beam EndsBeam Ends

Jeff NaumJeff Naum

Maine DOTMaine DOT

Bridge Bridge NomenclatureNomenclature

BearingsBearings

• BEARINGSBEARINGS• Components that transfer weight Components that transfer weight

from beams to abutments and piersfrom beams to abutments and piers

• BEAM ENDSBEAM ENDS• Ends of beams and girders often Ends of beams and girders often

over a bearingover a bearing

Bearings at AbutmentsBearings at Abutments

At Abutments and PiersAt Abutments and Piers

One Row of BearingsOne Row of Bearings

Two Rows of BearingsTwo Rows of Bearings

Bearings – Functions Bearings – Functions

• Transmit loads from Transmit loads from superstructure to substructuresuperstructure to substructure

• Allow rotation caused by loadingAllow rotation caused by loading• Allow movements caused by Allow movements caused by

thermal expansion and thermal expansion and contractioncontraction

Bearings – Functions Bearings – Functions

Main CategoriesMain Categories

• Expansion BearingsExpansion Bearings• Allow thermal movementsAllow thermal movements

• Steel Bridges = 1 ¼” per 100 ftSteel Bridges = 1 ¼” per 100 ft

• Concrete Bridges = 1” per 100 ftConcrete Bridges = 1” per 100 ft

• Fixed BearingsFixed Bearings• Restrains movementsRestrains movements

Fixed BearingFixed Bearing

Expansion BearingExpansion Bearing

Bearing ComponentsBearing Components

Types of BearingsTypes of Bearings

• Chosen based on: Chosen based on: • Length of spanLength of span

• SkewSkew

• CostCost

Sliding Plate BearingsSliding Plate Bearings

Rocker BearingRocker Bearing

Elastomeric BearingsElastomeric Bearings

Pot BearingsPot Bearings

Damage and DeteriorationDamage and Deterioration

• Caused by leaking joint from Caused by leaking joint from aboveabove

• Reduced by preservative actionsReduced by preservative actions• Rate of Deterioration increased if Rate of Deterioration increased if

not cleanednot cleaned

Pin WearPin Wear

Anchor BoltAnchor Bolt

Beam End CorrosionBeam End Corrosion

Beam End CorrosionBeam End Corrosion

Pedestal DamagePedestal Damage

RepairsRepairs

• May be necessary if capacity is May be necessary if capacity is compromisedcompromised

• CostlyCostly• Have other tasks that could be Have other tasks that could be

doingdoing

Block UpBlock Up

Refurbish Refurbish BearingsBearings

Jacking Up BearingsJacking Up Bearings

Jacking Up BearingsJacking Up Bearings

New Sharon – Sandy RiverNew Sharon – Sandy River

New Sharon – Sandy RiverNew Sharon – Sandy River

Structural Structural RehabilitationRehabilitation

Old Town – Stillwater #2Old Town – Stillwater #2

Old Town – Stillwater #2Old Town – Stillwater #2

PreservationPreservation

• Essential in getting the most life Essential in getting the most life out of bridgesout of bridges

• Easy to doEasy to do• Relatively inexpensiveRelatively inexpensive

• Starts with sealing the Starts with sealing the jointjoint

Bridge Cleaning and WashingBridge Cleaning and Washing

Fluid FilmFluid Film

Paint Paint

West Gardiner - TappanWest Gardiner - Tappan

West Gardiner - Tappan West Gardiner - Tappan

Paint Weathering SteelPaint Weathering Steel