OpenBridge Modeler

Assumptions and Limitations When Exporting to LEAP Bridge Concrete

Please be aware of the following assumptions and limitations when transferring the physical model from OpenBridge Modeler to an analytical model in LEAP Bridge Concrete, and bringing changes back from LEAP Bridge Concrete to OpenBridge Modeler.

  1. Data Transfer: In version 10.08.01.xx, the data transfer is bi-directional, i.e. from OpenBridge Modeler to LEAP Bridge Concrete (for all supported bridge types), and back from LEAP Bridge Concrete to OpenBridge Modeler (for prestressed concrete girder bridges). While the entire model is transferred from OpenBridge Modeler to LEAP Bridge Concrete, on the way back only selected superstructure (beams and beamlayout) and all substructure information is transferred. In LEAP Bridge Concrete, use the Tools > OBM Sync > Send to OBM option to write information back to OpenBridge Modeler via an XML file. In OpenBridge Modeler on the Interop tab of the ribbon toolbar, select LBC > Updateto select the same transfer XML file, and start the process of updating the OpenBridge Modeler model with LEAP Bridge Concrete data changes if any. At this time, any design reinforcement, strands or tendon information will not be transferred back from LEAP Bridge Concrete to OpenBridge Modeler.
  2. Model: Model must be completed in OpenBridge Modeler, with all super and substructure including bearings defined, before transferring to LEAP Bridge Concrete.
  3. Deck Slab Thickness: For a bridge model with varying deck thickness in spans, or across the cross-section in a single span, OpenBridge Modeler will transfer the minimum thickness of the slab across all cross-sections and all spans to LEAP Bridge Concrete. The deck thickness is not transferred back from LEAP Bridge Concrete to OpenBridge Modeler.
  4. Haunch Thickness: While OpenBridge Modeler 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 LEAP Bridge Concrete uses a constant haunch thickness. OpenBridge Modeler will conservatively transfer the maximum thickness from among all beams in all spans to LEAP Bridge Concrete. The haunch thickness is not transferred back from LEAP Bridge Concrete to OpenBridge Modeler.
  5. Beam Layout: LEAP Bridge Concrete only supports prestressed beams spanning between supports. End blocks modeled in OpenBridge Modeler with different sections will not be transferred to LEAP Bridge Concrete. Beam Layout (including spacing of beams) changes in LEAP Bridge Concrete can be transferred back to OpenBridge Modeler. User will have an opportunity to view and accept or reject changes before coming back to OpenBridge Modeler.
  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 OpenBridge Modeler to LEAP Bridge Concrete, LEAP Bridge Concrete 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 LEAP Bridge Concrete. When data is sent from LEAP Bridge Concrete to OpenBridge Modeler, 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. Concrete Diaphragms will not be transferred to the superstructure module of LEAP Bridge Concrete.
  8. For CIP P/T Box Girder bridges and RC or P/T Slab bridges: OpenBridge Modeler will transfer an interpreted cross-section, by populating the parametric variables, by intelligently interpreting the appropriate point pairs from OpenBridge Modeler template. A screen showing the OpenBridge Modeler Template and the interpreted cross-section is presented to the user before the final transfer to LEAP Bridge Concrete. In this screen the user can modify the points used for picking up the points from the OpenBridge Modeler templates. Changes from LEAP Bridge Concrete to OpenBridge Modeler for this bridge type is currently not supported.
  9. Bearings: LEAP Bridge Concrete can currently only handle rectangular shape bearings. Any other shape of bearing coming from OpenBridge Modeler is converted to equivalent rectangular bearing during transfer. Grout pads on top of the bearings in OpenBridge Modeler are not transferred to LEAP Bridge Concrete, but the thickness at the center is added to the bearing seat thickness to compensate. Changes from LEAP Bridge Concrete to OpenBridge Modeler for bearings is currently not supported.
  10. Materials: Beam material properties are transferred from OpenBridge Modeler to LEAP Bridge Concrete, and back into OpenBridge Modeler if changes are made in LEAP. A new entry is created in the OpenBridge Modeler materials library if an exact match of the materials modified in LEAP is not found.
  11. Substructure:
    1. Pier Location offset is measured in OpenBridge Modeler, along the SupportLine, whereas in LEAP Bridge Concrete it is measured perpendicular to the alignment. The conversion is done on the fly when data is transferred from OpenBridge Modeler to LEAP Bridge Concrete.
    2. Since LEAP Bridge Concrete does not support inclined/sloped pier cap, when such a cap is transferred from OpenBridge Modeler, it is treated as a straight/level cap and the bearing seats adjusted to fill in the gap under bearings/beams.
    3. Other than the Oval column shape from OpenBridge Modeler, all other 'regular' column shapes are supported in LEAP Bridge Concrete. The Oval shape column is converted to an equivalent rectangular shape with fillets. When transferring template based column cross-sections from OpenBridge Modeler, columns come in with a cross-section represented by a bounding rectangle around the shape. Variable pier caps with parabolic or circular variations are approximated by linear variations.
    4. For Abutments, to accommodate various agency practices, OpenBridge Modeler allows users to set three different locations (front face of backwall, centerline of abutment cap, back of abutment) as the reference line for placing abutments. Since LEAP Bridge Concrete only allows one reference line at center of abutment, OpenBridge Modeler on data transfer will maintain the accurate lengths of the girders, and adjust the position of abutment for an additional offset distance. Wingwalls are not transferred from OpenBridge Modeler to LEAP Bridge Concrete at this time.
    5. Integral substructures for Box Girder bridges and RC Slab bridges, with the integral cap taking the shape of the superstructure are currently not supported in OpenBridge Modeler. These will need to be modeled in LEAP Bridge Concrete, after initial model transfer from OpenBridge Modeler.
    6. All geometry changes made to substructure in LEAP Bridge Concrete can be brought back to OpenBridge Modeler. The user will have the opportunity to view and accept or reject the changes when updating the model in OpenBridge Modeler using the transfer XML format file.
    7. If you have modified the column length in LEAP and you want to update the column length in OpenBridge Modeler, please be sure to have the footings elevation constraints unchecked in order to see the updated model.
  12. Auxiliary/Barrier: In this release OpenBridge Modeler will not transfer Barriers or other Auxiliary bridge elements from OpenBridge Modeler to LEAP Bridge Concrete or vice-versa. User should model these elements in LEAP Bridge Concrete as appropriate loads.
  13. File Name: When attempting to transfer data from OpenBridge Modeler to LEAP Bridge Concrete, user can provide a file name and path for the LEAP Bridge Concrete data file. If such a file already exists, OpenBridge Modeler 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 LEAP Bridge Concrete, the results can be transferred back to OpenBridge Modeler. Using the Reports > Camber option, user can view the estimated beam elevation values at erection, and deck screed elevation reports.