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# Construction Stages

sens.20

## Highlights

 Successive assembling or casting of structural elements. Progressive construction of cross-sections. Gradual application of loads and prestressing. Changes of boundary conditions. Removal of temporary structural elements.

Since civil structures are frequently designed and constructed with miscellaneous materials (e.g. steel, prefab and in-situ cast concrete), the static system of the structure changes during its erection. This module enables you to calculate structures that consist of 1D and 2D elements in different phases. The stress history is calculated by taking into account added or removed supports, members, load cases, changing cross section properties etc.

Modern civil engineering structures are often designed and constructed as hybrid systems consisting of steel, pre-cast concrete and cast-in-place concrete. Main load-bearing elements are frequently fabricated in advance and are used as a supporting system for parts of a cross-section or structure to be produced later. Thus, the static system of the structure changes during its construction.

The evolution of the static system of the structure in each stage is taken into account through:

• added or removed 1D structural members,
• added of D members (plates and shells)
• added or removed supports,
• progressive construction of members (e.g. composite bridge deck),
• progressive construction of cross-sections (phased cross-sections),
• gradual application of loads and prestressing (when combined with “Prestressing modelling and analysis” module sens.21).
• variation of E modulus over time,
• redistribution of internal forces caused by creep and shrinkage (when combined with TDA analysis available in “Prestressing modelling and analysis” module sens.21).
• pre-tensioned tendons become an integral part of the structure after cutting. Their stiffness is added into the stiffness matrix of the structure. All loads carried by the structure will automatically cause the change of prestressing in that tendons (when combined with “Prestressing modelling and analysis” module sens.21).

As an extension to the linear calculation of construction stages, the nonlinear analysis considers in a specific stage the geometry of the deformed construction from the previous stage. In SCIA Engineer, this analysis type can be applied to 3D frame structures.

• Non-linear analysis of each stage. Non linearities which can be included:
• Non-linear supports.
• Beam non-linearity (e.g. tension or compression only).
• Non-linear hinges.
• Geometrical non-linearity (P-Delta effect).
• The initial Stress/Strain values for a stage are taken from the calculated result of the previous stage.

Included in Edition:
Expert
Ultimate

## More about this topic

• Prestressing modelling and analysis