Structural Analysis
CIP RC/PT Girder uses the structure and load descriptions as specified through the graphical user interface (GUI) to construct an internal representation of the box girder. CIP RC/PT Girder generates a finite element (FE) model and obtains displacement and force responses using the services of a finite element analysis engine.
The analysis engine contained within CIP RC/PT Girder is a powerful FE engine with the ability to handle general purpose, incremental solution, and time effects that has support for the following:
- Multiple creep, shrinkage, and relaxation models (CEB-FIP-1990, ACI-209, current LRFD)
- Cross sections with multiple parts (e.g., beams, slabs, and cast-in splice splices) may enter or leave during any interval. Mild reinforcing and post-tensioning are permanently applied to the box girder model and cannot be removed.
- Plane and space frame bending elements
- Plane and space truss elements
- Zero-length, 2-node bearing elements
- 1-node boundary elements
- Element force releases
- Finite size joints
- Non-conforming coordinate systems
- Master-slave node constraints
- Element self weight
- Node point loads
- Node point initial displacements
- Element point loads
- Element linear varying distributed loads
- Element initial strain loads
- Element shrinkage loads
- Element and node loads generated from post-tensioning loadings
- Elements may enter and leave at specified solution intervals
- Loadings may be applied and removed at specified solution intervals
The analysis is performed incrementally by forming element stiffness and element loadings interval-by-interval and then solving for the incremental displacements and rotations. Increment forces on the elements and cross section parts are computed on demand as needed. Total responses (displacements, element and section part forces) are obtained by summing the incremental responses.