What are the limitations and assumptions when transferring data from OBM to Superstructure of LEAP B

2. Model: Model must be completed in OBM, with all super and substructure including bearings defined, before transferring to LBC.

3. Deck Slab Thickness: For a bridge model with varying deck thickness in spans, or across the cross-section in a single span, OBM will transfer the minimum thickness of the slab across all cross-sections and all spans to LBC. The deck thickness is not transferred back from LBC to OBM.

3a. Multiple Decks: In the properties window, setting the Analytical Flag = true allows the deck to be transferred to LBC. Users should not mark approach slabs as analytical decks. A series of contiguous decks can also be transferred to LBC.

4. Haunch Thickness: While OBM models a very accurate haunch considering the slope of the deck transversely, and varying haunch thickness filling the gap between the top of the beam and the bottom of the slab, the analytical model in LBC uses a constant haunch thickness. OBM will conservatively transfer the maximum thickness from among all beams in all spans to LBC. The haunch thickness is not transferred back from LBC to OBM.

5. Beam Layout: LBC only supports prestressed beams spanning between supports. End blocks modeled in OBM with different sections will not be transferred to LBC. Beam Layout (including spacing of beams) changes in LBC can be transferred back to OBM. User will have an opportunity to view and accept or reject changes before coming back to OBM.

6. Beam Cross-sections: While transferring a beam cross-section from the non-LEAP library, i.e. a custom section which are typically drawn using MS drawing tools from OBM to LBC, LBC will first search for a matching name through its existing beam library, and if not will attempt to automatically create a new beam library object by interpreting a shape as close to the MS drawing as possible. The user may need to verify and modify this library object with appropriate structural properties and strand templates before continuing the design in LBC. When data is sent from LBC to OBM, changes to the Beam cross-section, if any, are flagged, and the user will have the opportunity to view and accept or reject the changes.

7. Diaphragm: Diaphragm defined in OBM is transferred in terms of the locations and equivalent point loads on concrete beams in LBC.

8. For CIP P/T Box Girder bridges and RC or P/T Slab bridges: OBM will transfer an interpreted cross-section, by populating the parametric variables, by intelligently interpreting the appropriate point pairs from OBM template. A screen showing the OBM Template and the interpreted cross-section is presented to the user before the final transfer to LBC. In this screen the user can modify the points used for picking up the points from the OBM templates. Changes from LBC to OBM for this bridge type is currently not supported.

9. Bearings: LBC can currently only handle rectangular shape bearings. Any other shape of bearing coming from OBM is converted to equivalent rectangular bearing during transfer. Grout pads on top of the bearings in OBM are not transferred to LBC, but the thickness at the center is added to the bearing seat thickness to compensate. Changes from LBC to OBM for bearings is currently not supported.

10. Materials: Beam material properties are transferred from OBM to LBC, and back into OBM if changes are made in LEAP. A new entry is created in the OBM materials library if an exact match of the materials modified in LEAP is not found.

12. Barrier: OBM will transfer Barriers from OBM to LBC as equivalent loads, and will also transfer the barrier width and location. User should check these loads and dimensions in LBC as these could affect the design.

13. File Name: When attempting to transfer data from OBM to LBC, user can provide a file name and path for the LBC data file. If such a file already exists, OBM will replace only the geometry and material data and retain all loads and other design parameter information.

14. Camber and Deflection results: If prestressed concrete beams are designed (with strands) in LBC, the results can be transferred back to OBM. Using the Reports > Camber option, user can view the estimated beam elevation values at erection, and deck screed elevation reports.

15. For offset (from alignment) bridges, OBM and LEAP Bridge support line stationing could be different due to differences in assumptions on layout in these two products. While the conversion is done on the fly and the bridge will be located geometrically accurate, future versions will address this issue.