Bridge Components Flashcards
COMPONENTS of a BRIDGE
- SUPERSTRUCTURE
- SUBSTRUCTURE
- FOUNDATION
Span and directly Receives the live load
Supported by bearings
deck, girders, slab above the main deck
SUPERSTRUCTURE
Support structures, located below the bearing
Transmits load to ground
piers, abutments, spandrels, caps, bearings
SUBSTRUCTURE
holds the shallow or deep base of the bridge
Footing; piles
FOUNDATION
COMPONENTS OF SUPERSTRUCTURE
- WEARING SURFACE
- DECK
- PRIMARY MEMBERS
- SECONDARY MEMBERS
- BEARINGS
OR Course
➢ Topmost layer of material
applied upon the deck to
provide smooth riding surface
and to protect deck from effects
of traffic and weathering
➢ In some instances, this is a
separate layer made of
bituminous material, while in
some it is an integral part of the
concrete deck
WEARING SURFACE
➢ The physical extension of the
roadway across the obstruction
to be bridged
➢ Component of the bridge to
which live load is directly applied
➢ Provide smooth and safe riding
surface for the traffic utilizing the
bridge and distribute loads
transversely along the bridge
cross section
DECK
TYPES OF DECK
➢ TIMBER DECKS
➢ CONCRETE DECKS
➢ STEEL DECKS
Normally referred to as decking or timber flooring
(limited to the roadway portion that receives
vehicular loads)
TIMBER DECKS
➢ Concrete permits casting in various shapes and sizes
and has provided bridge designers and builders a
variety of construction methods
➢ It is used together with reinforcement to resist
tensile stress (where concrete is weak)
CONCRETE DECKS
Composed of either
➢ Solid steel plate
➢ Steel grids
STEEL DECKS
Distributes loads longitudinally and are usually designed principally to resist flexure and shear
PRIMARY MEMBERS
BEAM TYPE primary members are
also referred to as
stringers or girders
placed between the deck slab and the top flange of
the stringer in order for the slab not to rest directly on the member
haunch
▪ Efficient for shorter spans
▪ Limited sizes and shapes
I – girders: Rolled Beams
▪ Deep girders can span very long distances
▪ Vast range of sizes and shapes
I – girders: Plate Girders
▪ Box section efficiently resists torsion effects
▪ Vast range of shape and sizes
Box Girders
➢ Are bracing between primary members
➢ designed to resist cross-sectional
deformation of the superstructure frame
➢ and help distribute part of the vertical
load between stringers
SECONDARY MEMBERS
Other secondary members (like _____________ ) composed of crossed frames at the top or bottom flanged of a stringer
➢ are used to ________________________ caused by loads acting perpendicularly to the bridge’s
longitudinal axis
lateral bracing; resist lateral deformation
TYPE OF SECONDARY MEMBERS
CROSS FRAMES
DIAPHRAMS
LATERAL BRACING
Used on steel girder bridges to provide torsional stiffness during construction and in final
condition
CROSS FRAMES
▪ Used on steel girder bridges to provide torsional stiffness during construction and in the final
condition
▪ Typically used on shallow beams
DIAPHRAMS
Used to provide lateral stiffness
and limit lateral deflections
LATERAL BRACING
➢ Are mechanical systems which
transmit the vertical and horizontal
loads of the superstructure to the
substructure
➢ Accommodates movement between
superstructure and substructure
➢ Use and functionality vary greatly
depending on the size and
configuration of bridge
BEARINGS
TYPES OF BEARINGS
➢ Expansion bearings
➢ Fixed bearings
Allow both rotation and longitudinal translation
Expansion bearings
Allow rotation only
Fixed bearings
EXAMPLES OF BEARINGS
Elastomeric Bearing
Rocker Bearing
Disc Bearing
Pot Bearing
Mechanical roller
components of SUBSTRUCTURE
- Abutments
- Piers
- Pedestals
- Stem
- Backwall
- Wingwall
- Footing
- Piles
- Sheeting
➢ Earth-retaining structures which
support the superstructure and
overpass roadway at both ends of
the bridge
➢ Like retaining walls, it resist
longitudinal forces of the earth
underneath the overpass roadway
➢ Connects the bridge with the
approach roadway
ABUTMENTS
➢ support the superstructure at
intermediate points between end
supports
➢ Bridges consisting of one span, does
not require
➢ From aesthetic standpoint:
➢ can make a bridge visually
pleasing (or unattractive) since it is
one of the most visible components
of a highway bridge
PIERS
Basic Types of Pier
Hammerhead
Solid wall or gravity
Column Bent
Pile Bent
▪ Also referred as solid shaft pier or Tpier
▪ Major stream crossings where heavy
loads, tall piers or sizable debris loads
may occur
▪ Looks attractive for bridges requiring
large clearance
HAMMER HEAD PIER
used for most stream crossings
to avoid collecting of debris
and floating ices between
columns
SOLID /GRAVITY WALL PIER
well suited for shallow water
crossings
PILE BENT PIER
Or also called open Bent
COLUMN BENT PIER
➢ Short column on an abutment or pier
under a bearing
➢ Directly supports a superstructure
primary member
➢ Normally designed with different
heights to obtain required bearing
elevations
PEDESTALS
used to refer to the
elevation at the top surface of the
pedestal
Bridge seat
➢ A primary component of the abutment supporting pedestals on top of a
footing
➢ Its main function is to transfer loads from superstructure to the foundation
STEM
➢ The component of the abutment acting as a retaining structure on top
of the stem
➢ Also supports the approach slab
BACKWALL
➢ Sidewall to the abutment backwall or stem
➢ Designed to assist in confining earth behind the abutment
WINGWALL
➢ As bearing transfer the superstructure loads to the substructure; abutments
and pier footings transfer load from the substructure to the subsoil or piles
FOOTING
A footing supported by soil without piles is called
spread footing
A footing supported by piles is known as
pile cap
When soil under a footing cannot provide adequate support for substructure (in terms of bearing capacity, overall stability, or settlement), support is obtained through piles, which extends down from the footing to
stronger soil layer or bedrock
PILES
Vertical planks driven to the ground to act as temporary retaining wall permitting excavation
SHEETING
➢ Any part of the bridge or bridge site which is NOT a major structural component yet serves some purpose in the overall functionality of the structure
➢ i.e. guide rails
➢ Bridge site, as an entity, possesses many different
components which, in one way or another, integrates with the structure
APPURTENANCE
APPURTENANCES and SITE-RELATED FEATURES
EMBANKMENT AND SLOPE PROTECTION
UNDERDRAIN
APPROACH
TRAFFIC BARRIERS
GUIDE RAILS
Other Parts:
1. BRIDGE TOWER
2. SPANDREL
3. EXPANSION JOINT
4. PARAPET
5. ANCHORAGE
6. APEX
- slope that tapers from the abutment to the underpass (embankment) is covered with a material, which should be both aesthetically pleasing and provide for proper drainage and erosion control
- form of slope protection varies greatly from region to region and is mostly dependent on specific environmental concerns and the types of
material readily available - For water way crossings, large stones are usually used for foundation scour protection.
slope protection
- provide proper drainage of a major substructure element, such as an abutment,
- a drainage system made of perforated pipe or other suitable conduit that transports runoff away from the structure and into appropriate
drainage channels (natural or man-made
UNDERDRAIN
- Section of overpass roadway which leads up to and away from the bridge abutments
- Helps evenly distribute traffic loads on the soil behind the abutment and minimize impact to the abutment which can result from differential settlement between abutment and approach
APPROACH
- protective device “used to shield
motorists from obstacles or slope
located along either side of roadway - can range from a guard rail made of
corrugated steel to reinforced
concrete parapets - On bridges, they are usually called
bridge railings.
TRAFFIC BARRIERS
Designed to keep people or vehicles
from losing their way into dangerous
or off-limit areas
GUIDE RAILS
➢ Sometimes called mast or pylons
➢ Vertical supporting part used for cable stayed or suspension bridge
➢ Made of high strength in-situ concrete
BRIDGE TOWER
the almost triangular space between the main pillar of the bridge and decking
SPANDREL
The space between two parts of the structure that allows expansion and
contraction
EXPANSION JOINT
A low wall that forms a barrier around the outer edges of a bridge
PARAPET
A point where the supporting elements of the bridge are connected to the ground
ANCHORAGE
➢ the uppermost portion o a bridge
➢ Called a CROWN for arch bridges
APEX
