1. Fabrication phase (Remove/release prefab formwork phase) of the structure
Fabrication phase (Remove/release prefab formwork phase) is dedicated exclusively for the calculation of the pre-stressed element, where only the dead load and the pre-stressing actions of the pre-stressed element or its part is taken in to account.
Structural model which contains more than one pre-stressed element is interpreted as trimmed (disjoined) structure, where each trimmed part is investigated as separate element, have no common relations:
Pre-stress actions (initial and acting) is generated/represented/placed on each trimmed (disjoined) pre-stressed element of the structural model separately.
Pre-stressed element is represented by the single cross-section. Pre-stressed element has more than one cross-section is not valid.
Fabrication phase (Remove/release prefab formwork phase) structural model has a set of predefined supports and releases, and can’t be changed by user input:
Supports: On the begin(“B”) and the end (“E”) of the structural element “Pinned” (Yr=Free, free rotation around Y axis) support is used.
Release: On the end (“E”) of the structural element as X = Free (free movement of the node in X direction).
2. Montage phase of the structure
During the "Montage" phase the pre-stressed and/or pre-fabricated (Prefab, without pre-stress features) only elements (cross-sections) are investigated. All other elements (sections) not marked pre-stressed and/or pre-fabricated are ignored;
Montage phase investigation assumes:
- Possible definition of restrains (supports and/or releases) specific for the montage phase only;
- Transient loads generation/definition;
- Transient loads combinations generation/definition;
- Structural analysis and code check including transient actions and the "Remove/release prefab formwork" phase gained forces/deformations.
3. Using of bi-material (pre-stressed + compressed layer) cross-section
By default, the compression layer of the cross-section used for the "Montage" phase is treated as the dead load, while the structural analysis calculation is performed using the section properties of the bottom layer of the cross-section, neglecting the compression layer.
The default situation for the "Montage" phase for the whole project can be changed using options: Customize -> Settings -> User list -> Phases.
The structural analysis and code check performed for the Remove/release prefab formwork phase is only subject to the prefabricated/pre-stressed part of the cross-section, while the compression layer is constantly accounted for in the "End of life" phase.
4. “Shortening” of the pre-stressed element during production phase
During the fabrication (Remove/release prefab formwork phase) pre-stressed element is influenced by the initial or acting axial forces. Axial actions invoke axial deformations, which is seen on the deflection line of the element:
The fabrication phase structural forces/deformations is kept also by using multi elemental structure. It causes appearance of discontinuous deflection line:
5. Calculation of the complex topology strip structure
Calculation using different cross-sections and/or pre-stress features over the length of the beam is optimized for the performance (internal splitting). This can cause inaccuracy in calculation (less than 0.1%) by compare to the separate calculated part of the structure (without optimization, internal integration).