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Prestressing

Option V of CEDRUS


The prestress module of CEDRUS is designed for the analysis and dimensioning of prestressed slabs with any type of shape. The effect of the prestress can either be taken into account by treating the prestress as an external action or by considering the effect on the resisting side in the structural design of non-pretensioned reinforcement. Due to a simple and practice-oriented input mechanism of the prestressing cables and an integrated design aid which allows a pre-dimensioning with only a few settings the prestressing module is also dedicated for casual users.


Pre-dimensioning

During the input procedure of prestressing cables a tool for pre-dimensioning inner fields of flat slabs can be used. The pre-dimensioning tool plots a sheet with all characteristical values.

  • Pre-dimensioning with only three input parameters: span width, imposed/permament loads and prestressing system
  • Suggestions for minimal slab thickness and prestress level
  • Estimation of stresses, deformations and dynamic behaviour
  • Output of the pre-dimensioning sheet

Defining Tendons

  • Interactive input mechanism with numerous features of the Graphics Editor
  • Straight or arbitrarly curved layout of the tendons in the floor plan
  • Default vertical tendon profile with supports
  • 3D view in any projection
  • Grouping of tendons

Tendon attributes

  • Steel quality
  • Bonded/unbonbed
  • Friction value
  • Area and number of strands
  • Minimal radius of curvature
  • Prestressing process with repeated stressing and relaxing at both cable ends

Support attributes

  • High point/low point/point of inflexion
  • Distance to bottom/top slab surface
  • Slope
  • Minimal radius of curvature
 

Profile plots

The profile plot is very useful as a starting point for a layout drawing. It provides a labeling mechanism of the tendons which can be configured individually. The labels are placed outside of the slab outline and can be used for a DXF export. The finalizing of the layout drawing is being done with a CAD program.

Tabular formated tendon data

In addition to the graphical plots tabular formated outputs can be generated containing all tendon data which can be used for verification and documentation. The output includes a table with geometry data and prestressing forces at any section point. In addition to the profile plot these outputs can be used as a starting plot for creating the layout drawing.

Analysis

  • Automized calculation of anchor forces and deviation forces and generation of corresponding external actions
  • Section forces, deformations and reactings resulting from prestressing actions
  • Ultimate state design of of non-pretensioned reinforcements (prestressing on resisting side)