CTQP Structures Inspection 1 — Questions and Answers
Question 1: What does 'form stripping time' or 'form removal time' mean in concrete bridge construction?
- The time required to erect the formwork system
- The minimum time after concrete placement that forms can be removed based on concrete strength (Correct answer)
- The time allotted to inspect forms before concrete is placed
- The allowable time between form reuse applications
Correct answer: The minimum time after concrete placement that forms can be removed based on concrete strength
Form stripping time is the minimum elapsed time after concrete is placed (or minimum concrete strength achieved) before forms can be safely removed without damaging the concrete.
Question 2: What is 'falsework' in bridge construction?
- Temporary steel framing used to erect bridge girders
- Temporary supporting structure that supports permanent structure elements during construction until they are self-supporting (Correct answer)
- Formwork panels used to shape concrete deck surfaces
- Temporary traffic barriers used during bridge construction
Correct answer: Temporary supporting structure that supports permanent structure elements during construction until they are self-supporting
Falsework is the temporary support structure (typically steel or timber framing) used to hold bridge girders, decks, or arches in position until the permanent structure can support its own load.
Question 3: What is the purpose of 'expansion joints' in a bridge structure?
- To allow the bridge to expand vertically during high loads
- To allow for thermal movement and prevent damage from temperature-induced expansion and contraction (Correct answer)
- To provide access for inspection of bridge components
- To connect precast girders to the bridge deck
Correct answer: To allow for thermal movement and prevent damage from temperature-induced expansion and contraction
Expansion joints accommodate thermal expansion and contraction, seismic movement, and long-term creep and shrinkage, preventing structural damage and cracking in the bridge.
Question 4: What is 'post-tensioning' in prestressed concrete bridge construction?
- Adding supplemental reinforcing steel after concrete cures
- Applying tension to steel tendons after the concrete has hardened to place the concrete in compression (Correct answer)
- Tightening anchor bolts after bridge erection
- Stressing the bridge deck after beam placement
Correct answer: Applying tension to steel tendons after the concrete has hardened to place the concrete in compression
Post-tensioning involves threading high-strength steel tendons through ducts cast into the concrete, then tensioning the tendons after the concrete has hardened to induce compressive prestress.
Question 5: What document must an inspector verify is current and on-site before allowing any concrete pour on a bridge structure?
- The contractor's payroll records
- The approved mix design and current concrete plant certification (Correct answer)
- The equipment maintenance log
- The environmental permit only
Correct answer: The approved mix design and current concrete plant certification
The inspector must verify that the concrete mix design is approved by FDOT and that the batch plant holds a current certification before allowing any structural concrete to be placed.
Question 6: What is the function of a 'bearing pad' in a bridge structure?
- A pad placed under bridge workers for safety during construction
- A device that transfers loads from the superstructure to the substructure while accommodating rotation and movement (Correct answer)
- A rubber pad installed between deck panels during erection
- A pad used to level the formwork before concrete placement
Correct answer: A device that transfers loads from the superstructure to the substructure while accommodating rotation and movement
Bearing pads transfer loads from the girders or superstructure to the bridge seats or caps below while allowing controlled rotation and horizontal movement due to live loads and temperature.
CTQP Structures Inspection 1
What does 'form stripping time' or 'form removal time' mean in concrete bridge construction?