General Operation

When the option of Abutment Design is selected in the Project tab the Geometry tab is transferred to present a simplified interface allowing users to enter the information related to abutment configuration, pile arrangement and bearing locations.

Graphical 3D view along with 2D drawings in elevation, section and plan view allow a user to check the accuracy of the model. Once a user starts defining the input in abutment configuration, switching to pier project will lose all changes.

Caution: Avoid switching to a different module while working in the middle of the project.

Integral Abutment

As is well known, the primary benefit of integral abutments is to offer joint-less bridges to improve the durability of the structure. The most common integral abutment type is the pile bent abutment. The connectivity with the abutments causes the structure to move as a whole also creating restraining moments at the top of abutments. This effect is addressed by integrating superstructure and substructure in the analysis.

Different states and provinces have different approaches to design integral abutments. The level of analysis performed varies from practically none to full bridge analysis including soil structure interaction. The continuity between the abutment and the superstructure is typically established after erection of girders. The implementation in LEAP Bridge incorporates the popular method of designing girders conservatively while accounting for restraint to abutments via superstructure connectivity. LEAP also uses the concept of user specified equivalent pile lengths in lieu of soil structure springs.

The integral abutment feature is only used for analyzing piers and abutments. Substructure workflow is the same as before. Users can import reactions from Precast/Prestressed Girder and CIP RC/PT Girder or generate them within Substructure. Piers and abutments are then analyzed for these loads as part of a full bridge 3D model. In other words, when the Integral Abutment option is selected, the superstructure will be fully connected to substructure at abutments. The Integral Abutment option has no impact on the connection between superstructure and substructure at intermediate piers.

There are no changes made to the superstructure analysis and design procedures. For example, in Precast/Prestressed Girder girders are not designed for the negative moments that may be caused by interaction with integral abutments. This is typically done to achieve conservative girder designs.