CPII Bridge Inspection 5 — Questions and Answers
Question 1: Which load rating vehicle is used for AASHTO legal load rating of bridges on the National Highway System?
- HS-20 design truck
- Type 3, 3-S2, and 3-3 legal trucks (Correct answer)
- EV2 and EV3 emergency vehicles
- SHV (Single-Unit Haul Vehicle)
Correct answer: Type 3, 3-S2, and 3-3 legal trucks
Legal load rating uses the AASHTO Type 3, 3-S2, and 3-3 standard legal trucks for routine commercial vehicle loads.
Question 2: An inspector observes diagonal tension cracks near the end of a reinforced concrete beam. What structural behavior is indicated?
- Flexural overload at mid-span
- Inadequate shear capacity near the support (Correct answer)
- Prestress loss at the anchorage zone
- Thermal expansion cracking
Correct answer: Inadequate shear capacity near the support
Diagonal tension cracks at approximately 45 degrees near beam ends indicate shear stress exceeding the beam's shear capacity.
Question 3: What information is recorded in NBI Item 113 (Scour Critical Bridges)?
- The depth of observed scour at the last inspection
- Whether the bridge is scour critical and the status of a scour action plan (Correct answer)
- The calculated scour depth at design flood
- The type of scour protection installed at the pier
Correct answer: Whether the bridge is scour critical and the status of a scour action plan
NBI Item 113 codes indicate whether a bridge is scour critical and whether a required scour plan of action has been completed.
Question 4: A through-truss bridge has a gusset plate with visible out-of-plane distortion. What is the inspector's most critical next step?
- Apply a condition rating of 4 and schedule a routine follow-up inspection
- Notify the bridge owner immediately and recommend an in-depth engineering evaluation (Correct answer)
- Document the distortion and continue the inspection without further action
- Apply a temporary load posting until the next scheduled inspection
Correct answer: Notify the bridge owner immediately and recommend an in-depth engineering evaluation
Gusset plate distortion in a truss is a potential sign of overload or buckling and requires immediate notification to the owner and an engineering evaluation.
Question 5: Which non-destructive evaluation (NDE) method is best suited for measuring the depth of corrosion-induced concrete cover loss without surface removal?
- Ground penetrating radar (GPR) (Correct answer)
- Half-cell potential measurement
- Infrared thermography
- Impact echo testing
Correct answer: Ground penetrating radar (GPR)
GPR can detect rebar depth, delamination, and voids beneath the concrete surface without requiring surface removal.
Question 6: Under AASHTO MBE, what is the Operating Rating?
- The maximum load that can travel over a bridge an unlimited number of times
- The maximum permissible load for occasional crossings that will not cause structural damage (Correct answer)
- The load at which the first section reaches its yield stress under combined dead and live load
- The load limit established for daily truck traffic postings
Correct answer: The maximum permissible load for occasional crossings that will not cause structural damage
The Operating Rating is the maximum load level the structure can carry occasionally without causing structural damage or permanent deformation.
Question 7: What condition warrants a bridge to be posted or closed under NBIS and AASHTO guidelines?
- Condition rating of 4 on any NBI item
- Load rating factor less than 1.0 for the applicable legal or posting vehicles (Correct answer)
- Sufficiency rating below 50
- Deck wear surface thickness below 1 inch
Correct answer: Load rating factor less than 1.0 for the applicable legal or posting vehicles
When the rating factor (RF) is less than 1.0 for applicable legal loads, the bridge must be posted or closed to prevent overloading.
CPII Bridge Inspection 5
Which load rating vehicle is used for AASHTO legal load rating of bridges on the National Highway System?