NHI 130055 Midterm (Modules 1.0 - 5.2) Exam and All Correct Answers.

NHI 130055 Midterm (Modules 1.0 - 5.2)
Exam and All Correct Answers.
3 Primary Bridge Components (in order) - Answer 1. Deck

2. Superstructure

3. Substructure



Elements of a Deck - Answer Deck

Wearing Surface

Bridge Railing

Sidewalk

Expansion Joint



Elements of a Superstructure - Answer Girder

Floorbeam

Stringer

Truss

Arch

Spandrel Columns

Cables

Cross Girder

Pin & Hanger Assemblies



Elements of a Substructure - Answer Columns/Piles

Walls

Abutments

Wingwalls

Pier Caps



Load Path - Answer Deck

Superstructure

Bearings

Substructure

Subsurface

,Function of Deck - Answer Supports live load



Function of Superstructure - Answer Transfers loads from deck to bearings and substructure



Function of Bearings (load path) - Answer Transmit loads from superstructure to
substructure



Function of Bearings (Other) - Answer Permits longitudinal expansion and contraction

Allows rotation caused by dead and live deflection



Function of Substructure - Answer Transfers loads from deck and superstructure into the
ground



Function of Culverts - Answer transmit the flow of water from one side of roadway to the
other (hydraulic structures that are typically underfill)



Axial Force - Answer A force which acts through the longitudinal axis of a member



Bending Moment - Answer A combination of tension and compression forces developed
when an external load is applied transversely to a bridge member, causing it to bend



Shear Force - Answer Results from equal but opposite transverse forces which tend to slide
one section of a member past the adjacent section



Torsional Force - Answer An external moment which tends to rotate or twist a member
about its longitudinal axis.



Stress - Answer Force per unit area and it denotes intensity of an internal force; may be
tension, compression, or shear



Deformation - Answer Local distortion or the change in shape of material due to applied
force



Strain - Answer Measure of deformation and it denotes around an object deforms WRT its
original dimensions



Creep - Answer Gradual, continuing irreversible deformation due to constant stress level
below yield strength

, Fatigue - Answer Tendency of a member to fail at stress below the yield stress when
subjected to cyclical loading



Elasticity - Answer Modulus of elasticity is the ration between the stress applied and
resulting elastic strain



Ductility - Answer Characteristic to undergo plastic deformation prior to failure



Brittleness - Answer Characteristic to fail while exhibiting little to no plastic deformation
prior to failure; can occur suddenly and without warning



Yield Strength - Answer Stress level at which plastic deformation begins



Tensile Strength - Answer Stress level defined by the maximum tensile load that material can
resist without failure



Toughness - Answer A measure of the energy required for a material to fail



Simple Span - Answer Only 2 supports, each of which is at or near the end of the span



Continuous Span - Answer 1 or more adjacent spans and the behavior of each span is
dependent on its adjacent span(s)



Cantilever Span - Answer A span with one end restrained against rotation and deflection and
the other end completely free



2 Common Methods of Steel Member Fabrication - Answer 1. Rolled Shapes

2. Built-up Shapes



5 Common Shapes Used in Steel Bridge Construction - Answer 1. Wire, Strand, & Cable

2. Plates

3. Bars

4. Rolled Shapes

5. Built-up Shapes



Physical Properties of Steel - Answer Resists impact and vibration