Precast/Prestressed Girder Help

Problem Data

Concrete Properties

Strength
  • Precast, release:5 ksi
  • Precast, 28 days:6 ksi
  • Cast-in-place topping, 28 days:4 ksi

Density, all concrete:150 pcf

Strand Properties

Strand Type: 1/2” - 270 K - Low relaxation (Es = 28,000 ksi)

Straight Pattern

Debond Constraints

Maximum 50% of strands in each row may be debonded

Maximum 50% of total number of strands may be debonded

Rebar Properties

Grade 60 rebar

Prestress Loss Information

  • Calculation Method:AASHTO LFD

  • Hours to release:18
  • Relative humidity:75%

Live Load

  • H/HS20 Lane
  • HS20 Truck

Dead Load

On precast:0.025 klf, due to stay-in-place forms (Model as DL)

Additional Dead Load

On composite:0.0375 ksf (applied over 32.0 ft) (Model as ADL)