PropertyValue
Default Short CommandLNOT
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Notional load function generates horizontal load from non-horizontal loads using a conversion factor.

1582804849244-917.pngNotional load generation needs user-defined Construction stages

The goal of this method is to consider the effect of the fact that the structures are not built at once, but storey by storey. This way a new storey is acting on a structure that already has displacements and internal forces.

Storeys must be defined to use Construction stages, since currently one storey is considered as one Stage.

Construction stages can be defined under the load tab. Click “Generate” button to create stages with the correspondent storey name.

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Columns in the table mean the following:

  • No: Number of the stage
  • Stage description: Name of storey which is built in the stage
  • (Prestress): if checked, in calculation of the stage displacements will be reset, but other results (internal forces) are kept
  • Activated load cases: Activated load cases for the stage
  • Partitioning:
    • only in this stage: Load cases activated in  the construction stage will act only in this stage.
    • from this stage on: Load cases activated in the construction stage will act in this and the later stages – loads that act on the storeys below this storey will also act in this stage
    • shifted from this stage: Load cases activated in the construction stage will act on this and the later stage - loads that act on the first storey will act in this stage, loads on second storey will act in the next stage, etc.

The following example shows the difference between “from this stage on” and “shifted from this stage” partitioning options. The model is a 4-storey frame with two load cases (1. and 2.).

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First we assign 1. load case to the first stage and the 2. load case to the second stage both partitioning option set to “from this stage”. The following picture shows the loading for each stage.

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Now if we assign 1. load case to the first stage with “from this stage” partitioning and 2. load case to the second stage with “shifted from this stage” option, the following pictures shows the loading for each stage.

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It’s possible to add any construction stage to any load combination with the following limtations :

  • Only one construction stage is allowed in one combination.
  • The fire and/or seismic load cases can be combined with only the final construction stage

For load groups only the final construction stage can be added to.

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The construction stages automatically follow all storey modifications.

 

User can start the construction stage calculation at Analysis/Calculation/Construction stages. There is two calculation method, so called Incremental “Tracking” method and “Ghost” structure method.

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When incremental method is chosen, the model is built stage-by-stage. In case of “ghost” structure method the full structure is in the calculation, but stiffness of those structural parts which aren’t in the specific stage is highly reduced.

Incremental “Tracking” method

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“Ghost” structure method

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The construction stage results can be found in the New results/Analysis/Construction stages.

For every stage result the method name and the displayed construction stage (e.g. CS.1 Storey 1) appears in the information panel.

If a construction stage result is displayed, a dialog appears where User can choose interactively for which construction stage he/she wants to see the result.

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It’s also possible to choose the construction stage in detailed results.

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The equilibrium dialog contains the construction stages, too.

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It’s possible to list the construction stages result, which can be found under Analysis/Construction stages.

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Load Cases in the project!

Definition steps

  1. Start the 1583248165547-347.png  Notional load command from Loads/Macro tabmenu.
  2. In the top of the dialog there is a textbox containing an automatically generated name for the notional load case, which can be changed arbitrarily.
  3. Click EC seismic notional load button, it indicates that Load case factor will be set according to parameters of Load groups the Load case belongs to. It uses EN 1990-1-1 A1.3.2 DK NA: 1583248227819-149.png
  4. Click Generate to create as many Notional Load cases, as many directions are chosen above the Generate button.

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The generated Notional Load Cases appear in the Load Cases dialog and they can be selected from Loads tab/Current load case drop-down list.

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Created by Fredrik Lagerström on 2020/04/02 17:50
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