• Only the following section types can be analyzed using this methodology:
  • I-girders
  • Adjacent Box Beams with cast-in-place (CIP) deck
  • Adjacent Box Beams without CIP deck but with post-tensioning
  • Spread Box Beams
• The grillage model for multi-beams is consistent with the one used to develop equations for type f and "G is sufficiently connected". Therefore, it cannot model a case where this continuity is not present. So it will not be able to apply this method in LRFD where there is no post-tensioned option selected (Adjacent Box Beams without deck).
• The skew angles are only used to compute more accurate Distribution Factors. Since Precast/Prestressed Girder always assumes that all precast girders in a span are the same length, you may typically input the span length measured at half of the bridge width as the design span length. Alternatively, you can input the length of the longest beam in each span as the span length to get more conservative results.
• For the I-girder type section, within the same span, the user can specify a different exterior beam size compared to interior beam properties. For both adjacent and spread box beams the dimensions and properties of all sections should be the same.
• There must be at least 3 beams in the cross-section for the FEM model to be set up and analyzed using refined methods of analyses.
• The distribution factor computation model always runs a HS20 Truck (without variable axle spacing) to compute the live load distribution factors in both code specification modes. Also the default gage width of 6 feet will be used in all cases.
• This version will not allow the selection of the refined method of computing DF for cases where the cross-sections are different in different spans (multi-span case).
• We are currently using the average of the curb widths (left+ right curb)/2 in the generation of the internal FEM model.
• There must be at least 3 beams in the cross-section for the FEM model to be set up and analyzed using refined methods of analyses.
• Internally, the case of no deck is modeled with a thickness of 0.1 inches.
• In general, the accuracy of this feature's results is lower for cases where response values are low (e.g., positive moments at interior supports of continuous spans or negative/positive moments at exterior simple supports).
• This feature is not available when the Flared Girder option is selected on the Project tab.

It is anticipated that this methodology currently implemented for the most common bridge cross-sections will be further extended to include more bridge types and more importantly truck gage widths in upcoming versions