PGSuper  3.1
Precast-prestressed Girder Bridges
Capacity/Demand Ratios

Capacity/Demand (C/D) ratios are reported in several places in PGSuper (examples are stresses, moment capacity,...) The rules for reporting the ratios are consistent throughout, and are as follows:

  • C/D is only computed when the algebraic signs of Capacity and Demand are the same
  • C/D's are reported using two decimal places in the form "(2.22)"
  • When C/D exceeds 10.0, it is reported as "(10+)"
  • When Demand exceeds Capacity the specification check is always reported as FAIL. A tolerance is never applied to make C/D equal 1.0.
  • For the case of zero capacity (e.g., zero allowable tension) C/D is not reported.
  • When Demand is 0.0 and Capacity is non-zero, C/D is reported as infinity.
  • For the case of sign reversals, C/D is reported as "(-)". For example, C is positive moment capacity and D is a negative moment.