Design Criteria

Standard beam designs must meet the following requirements:
  • Add and debond strands in the order shown on the Prestressed Decked Slab Beams Non-standard Designs (DSBND) standard drawings.
  • Debond strands in 3-ft. increments at beam ends if necessary to control stresses at release. If the strand size is larger than 0.6” diameter, base section increments on Article 5.9.4.3.3.
  • Debonded strands must conform to Article 5.9.4.3.3 except as noted below:
    • Debond no more than 50% of the total number of strands.
    • Debond no more than 50% of the number of strands in that row.
    • Replace Restriction B with, not more than 50% of the debonded strands, or 10 strands, whichever is greater, shall have the debonding terminated at any section, where section is defined as an increment (e.g., 3 feet, 6 feet, 9 feet).
    • Up to 75 percent of debonded strands may be used for the total number, the number of strands per row, and number terminated in a section as long as principal stress at or near the transfer length is designed for per Article 5.9.2.3.3, regardless of the concrete strength.
    • Do not design for Restriction E.
    • Replace Restriction G with, the maximum debonding length is the lesser of: (a) one-half the span length minus the maximum development length; (b) 0.2 times the beam length; or (c) 15 ft.
    • For multi-web sections having bottom flanges, replace Restriction J with:
      • Uniformly distribute debonded strands.
      • Bond the outer-most strand in each row.
  • Calculate required stirrup spacing for #4 Grade 60 bars according to the Article 5.7. Change stirrup spacing as shown on the DSBD standard drawing, only if analysis indicates the inadequacy of the standard design.
  • Standard decked slab beams satisfy Article 5.7.4 and Article 5.9.4.4.
  • Connect adjacent beams with lateral connectors, shown on standard drawing DSBD, spaced at 5 ft. maximum, with the first lateral connectors set 1 ft. from bent centerlines. See span standard drawings for completion of lateral connection details.
  • See Section 4, Pretensioned Concrete I-Girders, for other design criteria.