NHI QUESTIONS & COMPLETE
CORRECT ANSWERS
List common terminology for bridges and culverts - Correct Answer ✔✔ Bridge: Deck,
Superstructure, Substructure
Culverts: Rigid & Flexible
Describe the following functions:
Deck
Wearing Surface
Deck Joints
Drainage
Roadway Appurtenances
Superstructure Elements
Bearings
Substructure
Culvert Elements - Correct Answer ✔✔ Deck: Support live load, Provides run off for rain
or snow.
Wearing surface: Protect the top surface of the deck, and Provides a smooth ridings
surface
Deck Joints: Allows for bridge expansions and contractions due to temperature
fluctuations. Allows end rotation due to living load deflections—the smooth transition
between bridge and approach roadway. Protect underlying bearings and elements from
moisture and debris.
Drainage: Allows roadway precipitation to exit away from bridge elements.
Roadway Appurtenances: Minimize hazards for traffic on the highways and waterways.
Signs guide motorists and pederstrians. Lights enable you to see at night or regulate
traffic. Barriers prevent vehicles from falling off a bridge and smoothly redirect errant
vehicles back to their intended paths.
Superstructure Elements: Support deck, Transfer loads from deck to bearings and
substructures. Stringer transmits loads from deck to floor beam. Floor beams transmit
loads from the deck (or stringer, if present) to longitudinal girders, trusses, and arches.
Bearings: Transmit loads from superstructure to substructure. Permits longitudinal
expansion and construction. Allows rotation caused by dead and live load deflection.
, Substructure: Support superstructure. Transfer loads from desk and superstructure into
the ground.
Culvert Elements: Culverts transmit the flow of water from one side of the roadway to
the other. Culverts are the hydraulic structure that is underfilled. Headwalls help
stabilize culverts. Dingwall stabilizes the roadway and guides water through or away
from the culvert.
Compare and contrast the differences between components and elements - Correct
Answer ✔✔ Components: Deck, superstructure, substructure
Elements: Girder, cross girder, bearing, pier wall, pier cap, drainage pipe, floor beam,
stringer
Name the two principle categories of bridge loadings - Correct Answer ✔✔ 1)
Permanent loads
2) Transient loads
Describe the four types of applied forces resisted by bridge members - Correct Answer
✔✔ 1) Axial force: a force which acts through the longitudinal axis of a member.
2) Bending moment: a combination of tension and compression forces developed when
an external load is applied transversely to a bridge member causing it to bend.
3) Shear Force: results from equal but opposite transverse forces which tend to slide
one section of a member past the adjacent section.
4) Torsional force: results from an external moment which tends to rotate or twist a
member about its longitudinal axis.
Identify material responses and properties - Correct Answer ✔✔ Stress: force per unit
area and it denotes the intensity of an internal force; maybe tension, compression, or
shear.
Deformation: local distortion for the change in the shape of material due to the applied
force.
Strain: a measure of deformation and it denotes amount an object deforms with respect
to its original dimension.
Creep: gradual, continuing irreversible deformation due to constant stress level below
yield strength.
Fatigue: the tendency of a member to fail at stress below the yield stress when
subjected to cyclical loading.
CORRECT ANSWERS
List common terminology for bridges and culverts - Correct Answer ✔✔ Bridge: Deck,
Superstructure, Substructure
Culverts: Rigid & Flexible
Describe the following functions:
Deck
Wearing Surface
Deck Joints
Drainage
Roadway Appurtenances
Superstructure Elements
Bearings
Substructure
Culvert Elements - Correct Answer ✔✔ Deck: Support live load, Provides run off for rain
or snow.
Wearing surface: Protect the top surface of the deck, and Provides a smooth ridings
surface
Deck Joints: Allows for bridge expansions and contractions due to temperature
fluctuations. Allows end rotation due to living load deflections—the smooth transition
between bridge and approach roadway. Protect underlying bearings and elements from
moisture and debris.
Drainage: Allows roadway precipitation to exit away from bridge elements.
Roadway Appurtenances: Minimize hazards for traffic on the highways and waterways.
Signs guide motorists and pederstrians. Lights enable you to see at night or regulate
traffic. Barriers prevent vehicles from falling off a bridge and smoothly redirect errant
vehicles back to their intended paths.
Superstructure Elements: Support deck, Transfer loads from deck to bearings and
substructures. Stringer transmits loads from deck to floor beam. Floor beams transmit
loads from the deck (or stringer, if present) to longitudinal girders, trusses, and arches.
Bearings: Transmit loads from superstructure to substructure. Permits longitudinal
expansion and construction. Allows rotation caused by dead and live load deflection.
, Substructure: Support superstructure. Transfer loads from desk and superstructure into
the ground.
Culvert Elements: Culverts transmit the flow of water from one side of the roadway to
the other. Culverts are the hydraulic structure that is underfilled. Headwalls help
stabilize culverts. Dingwall stabilizes the roadway and guides water through or away
from the culvert.
Compare and contrast the differences between components and elements - Correct
Answer ✔✔ Components: Deck, superstructure, substructure
Elements: Girder, cross girder, bearing, pier wall, pier cap, drainage pipe, floor beam,
stringer
Name the two principle categories of bridge loadings - Correct Answer ✔✔ 1)
Permanent loads
2) Transient loads
Describe the four types of applied forces resisted by bridge members - Correct Answer
✔✔ 1) Axial force: a force which acts through the longitudinal axis of a member.
2) Bending moment: a combination of tension and compression forces developed when
an external load is applied transversely to a bridge member causing it to bend.
3) Shear Force: results from equal but opposite transverse forces which tend to slide
one section of a member past the adjacent section.
4) Torsional force: results from an external moment which tends to rotate or twist a
member about its longitudinal axis.
Identify material responses and properties - Correct Answer ✔✔ Stress: force per unit
area and it denotes the intensity of an internal force; maybe tension, compression, or
shear.
Deformation: local distortion for the change in the shape of material due to the applied
force.
Strain: a measure of deformation and it denotes amount an object deforms with respect
to its original dimension.
Creep: gradual, continuing irreversible deformation due to constant stress level below
yield strength.
Fatigue: the tendency of a member to fail at stress below the yield stress when
subjected to cyclical loading.
