3DFrame-NLGeom

Posted on 13/02/2025 by dougaj4

The VBA version of the 3DFrame spreadsheet has now been updated to allow geometric non-linear effects to be included. The new version can be downloaded from:

3DFrame.zip

For more details of the VBA 3DFrame see 3DFrame update, and for the Python version, which also includes non-linear materials analysis and combination of multiple load cases see 3DFrame-py-comb.

The input for the new 3DFrame-NLGeom spreadsheet allows for setting the maximum number of load iterations and the relative displacement tolerance.

The output format is the same as previous VBA versions, except the number of iterations and maximum displacement error are now shown.

In the screenshots below bending moment and deflection results for a portal frame with very high vertical and horizontal loads are compared with Strand7 results, also allowing for geometric non-linear effects, with linear elastic material properties. The results are in very close agreement for all cases.

Posted in Beam Bending, Excel, Finite Element Analysis, Frame Analysis, Newton, Strand7, VBA | Tagged , , , , , | 3 Comments

RC Design Functions 9.07

Posted on 08/02/2025 by dougaj4

The UMomPF function performs ultimate load analysis for codes using the partial factor approach, including Eurocode 2. The input for Eurocode 2 includes an optional table allowing alternative values to be input for various parameters, including stress reduction factors, and stress block definition values. It was recently pointed out that some of these parameters were having no effect on the results. This has now been fixed, and the revised file has been uploaded to:

RC Design Functions9.zip

The example below shows results for a section with axial load close to the balance load, first with default Eurocode 2 parameters (click on any image for full-size view):

Then with the reduction factors adjusted to be equivalent to the AS 3600 value for sections in compression, and the stress block set to rectangular, with stress and depth equal to the AS 3600 values for 50 MPa concrete:

Posted in Beam Bending, Concrete, Excel, Newton, UDFs, VBA | Tagged , , , , , , | 1 Comment

3DFrame-py-comb

Posted on 01/02/2025 by dougaj4

The 3DFrame-py spreadsheet has now been updated with provisions for saving multiple load cases and the associated results, and analysis with factored combinations of multiple load cases.

The new files can be downloaded from:

3DFrame-py.zip

See Installing 3DFrame-py for installation details, and details of other Python modules required. Also see Python and pyxll for details of the required pyxll package, including a coupon code for a 10% discount.

Load cases are entered and saved on the Input 2 sheet:

Factored load combinations can then be defined on the Combinations sheet:

The analysis is then run on the Output sheet:

This sheet has the following new options:

  • Calculate the current load case or any one or all of the saved load cases or load combinations.
  • Retrieve results from any saved case or combination.
  • Delete all stored cases or combinations.

Deflections and bending moments are shown below for a portal frame under very high vertical and transverse loads, including geometric non-linear results. Results are very close to Strand7 results, which are also plotted in the graphs, and display as the same line:

Posted in Beam Bending, Excel, Finite Element Analysis, Frame Analysis, Link to Python, Newton, PyXLL, Strand7, UDFs | Tagged , , , , , , , , , , | 1 Comment

What to do when download links don’t work

Posted on 19/01/2025 by dougaj4

Many of the download links here in older posts use the format http:// rather than https://, and these links now don’t work in Windows. If you find a non-working download link, here is what you can do:

  • Leave a comment, and I will fix the link.
  • Go to the Downloads tab, where there are working links to all available downloads.
  • Right click on the link, select “copy link”, then paste it in the address bar, add the s after http, and hit enter.
Posted in Computing - general | Tagged , , | Leave a comment

3DFrame-py rel. 0.40

Posted on 01/01/2025 by dougaj4

A new version of 3DFrame-py has been released and can be downloaded from:

3DFrame-py.zip

See Installing 3DFrame-py for installation details, and details of other Python modules required. Also see Python and pyxll for details of the required pyxll package, including a coupon code for a 10% discount.

The main changes are:

  • Beam bending moment results allowing for non-linear geometric effects have been corrected for axial load effects.
  • The moment-curvature adjustment routine has been changed to improve convergence for highly non-linear conditions.
  • The output sheet now includes a record of the number of non-linear iterations, and the maximum normalised displacement error for the last iteration.

The results have been compared with a Strand7 model of the portal frame used in previous checks, but rotated through 45 degrees in plan:

For linear-elastic analysis the spreadsheet results are near exactly equal to Strand7:

For non-linear analysis different approximations are used for both geometric and material non-linear effects, so there are very small differences in the results:

Posted in Beam Bending, Excel, Finite Element Analysis, Frame Analysis, Link to Python, Newton, PyXLL, Strand7, UDFs | Tagged , , , , , , , , , | 5 Comments