NHI NSTM || ALL ANSWERS ARE FLAWLESS.
Silver Bridge 1967 correct answers eye bar chain suspension bridge, unstable internal crack in
eye bar, bridge not maintained well, research began on redundancy, fatigue and failure from this,
NBIS
Mianus River Bridge correct answers pin and hanger was cracked and worsened due to fatigue,
pin separated from hanger, FHWA published " inspection of fracture critical bridge members
Daniel W. Hoan Memorial Bridge correct answers triaxial constraint ending in brittle fracture,
two main girders were completely severed because of a gusset plate and transverse connection
plate
I 35W Bridge correct answers gusset plates were half the thickness they were supposed to be,
bowing was shown
Sherman Minton Bridge correct answers fabrication flaw, cracks in one of the tie girders dating
back to original construction, T-1 steel, which is susceptible to hydrogen induced cracking
I-5 Skagit River Bridge correct answers Semi trailer over loaded directly hit multiple sway struts,
not considered NSTM, but makes inspectors aware of other components that can cause failure,
truck was not in the correct lane
I-276 Delaware River Turnpike Bridge correct answers plug weld, complete fracture in the top
tension chord, unused rivet holes filled with weldment
Hernando de Soto Bridge correct answers T-1 steel was used, similar as Sherman, partial fracture
in tie girder
Fracture Control Plan Factors correct answers Materials, Design and Fabrication
, 1985 correct answers Elimination of web gaps, designs after this shouldn't involve NSTM
members
Why are there more NSTM bridges in north east/ bigger states correct answers Access to
resources, more river crossings
What is NSTM correct answers primary steel member fully or partially in tension, and without
load path redundancy, system and internal, whose failures may cause a portion of or the entire
bridge to collapse
What is an NSTM inspection correct answers Hands on, touching entire member from front to
back and top to bottom, prior to site visit, must review NSTM procedures and plans and identify
NSTM
NSTM Inspection intervals correct answers Reduced- 12 months
Regular- 24 months
Extended- 48 months
Axial Tension correct answers A force that acts along the longitudinal axis of a member and
tends to pull the member apart
Axial Tension examples correct answers eye bars, cable, wire rope, FB, girders, truss, pin and
hanger
Axial Compression correct answers A force that acts along the longitudinal axis of member and
tends to push the member together
Axial Compression Examples correct answers columns, arches, vertical and diagonal trusses
Silver Bridge 1967 correct answers eye bar chain suspension bridge, unstable internal crack in
eye bar, bridge not maintained well, research began on redundancy, fatigue and failure from this,
NBIS
Mianus River Bridge correct answers pin and hanger was cracked and worsened due to fatigue,
pin separated from hanger, FHWA published " inspection of fracture critical bridge members
Daniel W. Hoan Memorial Bridge correct answers triaxial constraint ending in brittle fracture,
two main girders were completely severed because of a gusset plate and transverse connection
plate
I 35W Bridge correct answers gusset plates were half the thickness they were supposed to be,
bowing was shown
Sherman Minton Bridge correct answers fabrication flaw, cracks in one of the tie girders dating
back to original construction, T-1 steel, which is susceptible to hydrogen induced cracking
I-5 Skagit River Bridge correct answers Semi trailer over loaded directly hit multiple sway struts,
not considered NSTM, but makes inspectors aware of other components that can cause failure,
truck was not in the correct lane
I-276 Delaware River Turnpike Bridge correct answers plug weld, complete fracture in the top
tension chord, unused rivet holes filled with weldment
Hernando de Soto Bridge correct answers T-1 steel was used, similar as Sherman, partial fracture
in tie girder
Fracture Control Plan Factors correct answers Materials, Design and Fabrication
, 1985 correct answers Elimination of web gaps, designs after this shouldn't involve NSTM
members
Why are there more NSTM bridges in north east/ bigger states correct answers Access to
resources, more river crossings
What is NSTM correct answers primary steel member fully or partially in tension, and without
load path redundancy, system and internal, whose failures may cause a portion of or the entire
bridge to collapse
What is an NSTM inspection correct answers Hands on, touching entire member from front to
back and top to bottom, prior to site visit, must review NSTM procedures and plans and identify
NSTM
NSTM Inspection intervals correct answers Reduced- 12 months
Regular- 24 months
Extended- 48 months
Axial Tension correct answers A force that acts along the longitudinal axis of a member and
tends to pull the member apart
Axial Tension examples correct answers eye bars, cable, wire rope, FB, girders, truss, pin and
hanger
Axial Compression correct answers A force that acts along the longitudinal axis of member and
tends to push the member together
Axial Compression Examples correct answers columns, arches, vertical and diagonal trusses
