Construction stages and design stages
Construction stages
Floor levels (specifically, levels marked as floors) denote potential construction stages. Default construction stages are automatically created so that members in a floor level or attached to that level from below form an individual construction stage. You can reassign members between stages if required.
Each construction stage is assigned a stage duration (in weeks).
When the staged construction analysis is performed, each construction stage is analyzed sequentially for the Staged Construction combination only.
Stresses that develop in one construction stage become “Locked-in stresses” that are input to the following stage. At the end of the construction stages there is a set of “Locked-in stresses” that are carried through to the design stages.
Design stages
Design stages only come in to play after the end of construction, (so they don't have stage durations).
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Persistent Loading - Strength
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Persistent Loading - Service
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Transient Loading - Strength
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Transient Loading - Service
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Seismic Loading
When the staged construction analysis and design is performed, the Gravity, Lateral and Seismic combinations are automatically assigned to a design stage according to loadcase types contained within the combination. For example, any combination including wind will be considered transient and will be analyzed using properties appropriate to the "Transient Loading - Strength" and "Transient Loading - Service" design stages.
The rules for the assignment are as follows:
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IF a combination includes any seismic case it is assigned to the Seismic Loading design stage.
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ELSE IF a combination includes any of the following cases it considered as Transient Loading:
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Wind
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Snow
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MLL
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Temperature
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ELSE the combination is considered as Persistent Loading
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The Strength (ULS) and Service (SLS) variants of the combination are then separated as appropriate.
The Gravity, Lateral and Seismic combinations are then designed accordingly, (the Staged Construction combination is not designed).