Design Settings > Analysis
The settings displayed on this page are dependent on the regional code being worked to.
United States (ACI/AISC)
| Analysis | |
|---|---|
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First-order/second-order analysis radio buttons |
For 3D building analysis and staged construction analysis these allow you to select if a first or second order analysis is performed. For the US region the options presented are:
Tip:
For steel structures in particular you should consider running a first-order analysis for the initial gravity design before switching to a second-order analysis for the final design. |
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Note:
In addition to the 3D building analysis results from the method selected above, FE and grillage chasedown results are also generally considered, with the following exceptions:
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| Solve lateral loadcases in isolation if non-linear analysis is required during design |
Selecting this option allows you to try to solver lateral loadcases in isolation if non-linear analysis is required. However, in non-linear analysis, lateral loadcases often fail to solve or take a long time to converge when considered in isolation, especially for compression only foundation mats. Therefore, we recommend that you leave the option cleared. If you need to see the results for the individual lateral loadcases, you can either run the analysis directly on the Analyze ribbon, or select this option if you know that the analysis does not fail. |
| Stability coefficient tolerance | |
|---|---|
| Stack height / ratio |
This ratio allows you to adjust the value of deflection that can safely be ignored. Selecting the option prevents any small deflections from causing erroneously high stability coefficients in stability coefficient calculations. |
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Note:
If the second order drift is less than the tolerance specified in Stack height /, the stability coefficient value is returned as N/A with a note that states that the drift is small enough to be ignored. |
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| Reduced Stiffness | |
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| Reduced stiffness factor |
This factor is only exposed once the analysis is set to second-order. It is applied to the stiffness (EI and EA) of all steel members in addition to any settings made on Analysis Options, Modification Factors. For correct design to the AISC Specification using the DAM, it should be set to 0.8. |
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Note:
As an alternative to setting the analysis to first-order to explore the reason for any second order analysis failure, it is possible to alter this factor. If you set it to a value of say 10, this will stiffen both the Modulus of elasticity (E) and the shear modulus of elasticity (G) by a factor of 10 in the second order analysis. Although the results will not be able to be used for a valid design, it should now be possible to run the analysis to see which member might fail a design and hence be the cause of the analysis instability. This factor can then be reduced towards 0.8 for further investigation. |
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| Staged Construction Analysis | |
|---|---|
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Include staged construction analysis |
Select this option to include a staged construction analysis in the analysis and design process. For details of the implications this can have on the "envelope" of forces used for design, see: Design comparison - with and without staged construction |
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3D building analysis FE chasedown Grillage chasedown |
These options only become available if Include staged construction analysis has been selected. Select the results that should continue to be considered for member design alongside the staged construction results. |
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Note:
When staged construction analysis is selected, if the FE and/or grillage chasedown results are also considered, the following exceptions apply:
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All Eurocode regions
| Analysis | |
|---|---|
|
First-order/second-order analysis radio buttons |
For 3D building analysis and staged construction analysis these allow you to select if a first or second order analysis is performed. The options presented for the Eurocode regions are:
Tip:
For steel structures in particular you should consider running a first-order analysis for the initial gravity design before switching to a second-order analysis for the final design. |
|
Note:
In addition to the 3D building analysis results from the method selected above, FE and grillage chasedown results are also generally considered, with the following exceptions:
|
|
| Solve lateral loadcases in isolation if non-linear analysis is required during design |
Selecting this option allows you to try to solver lateral loadcases in isolation if non-linear analysis is required. However, in non-linear analysis, lateral loadcases often fail to solve or take a long time to converge when considered in isolation, especially for compression only foundation mats. Therefore, we recommend that you leave the option cleared. If you need to see the results for the individual lateral loadcases, you can either run the analysis directly on the Analyze ribbon, or select this option if you know that the analysis does not fail. |
| Staged Construction Analysis | |
|---|---|
|
Include staged construction analysis |
Select this option to include a staged construction analysis in the analysis and design process. For details of the implications this can have on the "envelope" of forces used for design, see: Design comparison - with and without staged construction |
|
3D building analysis FE chasedown Grillage chasedown |
These options only become available if Include staged construction analysis has been selected. Select the results that should continue to be considered for member design alongside the staged construction results. |
|
Note:
When staged construction analysis is selected, if the FE and/or grillage chasedown results are also considered, the following exceptions apply:
|
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All British Standards regions
| Analysis | |
|---|---|
|
First-order/second-order analysis radio buttons |
For 3D building analysis and staged construction analysis these allow you to select if a first or second order analysis is performed. The options that are presented for the British Standards regions are:
Tip:
For steel structures in particular you should consider running a first-order analysis for the initial gravity design before switching to a second-order analysis for the final design. |
|
Note:
In addition to the 3D building analysis results from the method selected above, FE and grillage chasedown results are also generally considered, with the following exceptions:
|
|
| Solve lateral loadcases in isolation if non-linear analysis is required during design |
Selecting this option allows you to try to solver lateral loadcases in isolation if non-linear analysis is required. However, in non-linear analysis, lateral loadcases often fail to solve or take a long time to converge when considered in isolation, especially for compression only foundation mats. Therefore, we recommend that you leave the option cleared. If you need to see the results for the individual lateral loadcases, you can either run the analysis directly on the Analyze ribbon, or select this option if you know that the analysis does not fail. |
| Staged Construction Analysis | |
|---|---|
|
Include staged construction analysis |
Select this option to include a staged construction analysis in the analysis and design process. For details of the implications this can have on the "envelope" of forces used for design, see: Design comparison - with and without staged construction |
|
3D building analysis FE chasedown Grillage chasedown |
These options only become available if Include staged construction analysis has been selected. Select the results that should continue to be considered for member design alongside the staged construction results. |
|
Note:
When staged construction analysis is selected the following exceptions apply when selecting the other results to be considered for member design:
|
|
India
| Analysis | |
|---|---|
|
First-order/second-order analysis radio buttons |
For 3D building analysis and staged construction analysis these allow you to select if a first or second order analysis is performed. The options that are presented for the India are:
Tip:
For steel structures in particular you should consider running a first-order analysis for the initial gravity design before switching to a second-order analysis for the final design. |
|
Note:
In addition to the 3D building analysis results from the method selected above, FE and grillage chasedown results are also generally considered, with the following exceptions:
|
|
| Solve lateral loadcases in isolation if non-linear analysis is required during design |
Selecting this option allows you to try to solver lateral loadcases in isolation if non-linear analysis is required. However, in non-linear analysis, lateral loadcases often fail to solve or take a long time to converge when considered in isolation, especially for compression only foundation mats. Therefore, we recommend that you leave the option cleared. If you need to see the results for the individual lateral loadcases, you can either run the analysis directly on the Analyze ribbon, or select this option if you know that the analysis does not fail. |
| Staged Construction Analysis | |
|---|---|
|
Include staged construction analysis |
Select this option to include a staged construction analysis in the analysis and design process. For details of the implications this can have on the "envelope" of forces used for design, see: Design comparison - with and without staged construction |
|
3D building analysis FE chasedown Grillage chasedown |
These options only become available if Include staged construction analysis has been selected. Select the results that should continue to be considered for member design alongside the staged construction results. |
|
Note:
When staged construction analysis is selected the following exceptions apply when selecting the other results to be considered for member design:
|
|
Australia
| Analysis | |
|---|---|
|
First-order/second-order analysis radio buttons |
For 3D building analysis and staged construction analysis these allow you to select if a first or second order analysis is performed. The options that are presented for the Australia are:
Tip:
For steel structures in particular you should consider running a first-order analysis for the initial gravity design before switching to a second-order analysis for the final design. |
|
Note:
In addition to the 3D building analysis results from the method selected above, FE and grillage chasedown results are also generally considered, with the following exceptions:
|
|
| Solve lateral loadcases in isolation if non-linear analysis is required during design |
Selecting this option allows you to try to solver lateral loadcases in isolation if non-linear analysis is required. However, in non-linear analysis, lateral loadcases often fail to solve or take a long time to converge when considered in isolation, especially for compression only foundation mats. Therefore, we recommend that you leave the option cleared. If you need to see the results for the individual lateral loadcases, you can either run the analysis directly on the Analyze ribbon, or select this option if you know that the analysis does not fail. |
| Staged Construction Analysis | |
|---|---|
|
Include staged construction analysis |
Select this option to include a staged construction analysis in the analysis and design process. For details of the implications this can have on the "envelope" of forces used for design, see: Design comparison - with and without staged construction |
|
3D building analysis FE chasedown Grillage chasedown |
These options only become available if Include staged construction analysis has been selected. Select the results that should continue to be considered for member design alongside the staged construction results. |
|
Note:
When staged construction analysis is selected the following exceptions apply when selecting the other results to be considered for member design:
|
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