Frame Analysis with Excel – 4, 2D frame analysis

Continuing from: Frame Analysis with Excel – 3, Continuous beam or frame

Download Frame1.zip - the download file includes complete open source code.

The continuous beam spreadsheet presented in the previous post has been modified to deal with 2D frames where any nodes may be connected, and to deal with much bigger structures.  The changes that have been made are:

  1. The input has been rearranged to allow (in principle) data to be limited only by the number of rows in the spreadsheet.  I say “in principle” because the size of the problem that can be handled is still limited by Excel’s matrix handling capabilities, and for Excel 2003 and earlier this is a restrictive limitation, but this will be fixed in future versions.
  2. The routine for forming the global stiffness matrix no longer assumes that beams are connected end to end in a single line, any 2D arrangement of beams is noe possible.
  3. The matrix arithmatic operations are now carried out in VBA, rather than on the spreadsheet.

Screenshots below show the new input screens, and the results of the analysis of a 16 bay truss structure, compared with the analysis of the same structure in Strand7.  Note that in the current version this structure is too large for Excel 2003 and earlier, but in the next version a VBA routine for the solution of the stiffness matrix equations will be incorporated, which will allow the analysis of much larger structures.

Input of beam properties, node coordinates, node restraints, and beam connections and property types

Input of beam properties, node coordinates, node restraints, and beam connections and property types

 

Input of member loads

Input of member loads

Inclined truss

Inclined truss

Results of truss analysis compared with Strand7 results for the same structure

Results of truss analysis compared with Strand7 results for the same structure

3 Responses

  1. Hi Doug,

    I developed a similar 2D Frame / Truss analysis software as a term project at university which includes graphical representation of input and deflected structure. The analysis is all performed in VBA. Shear and P-delta deformations are also considered in the analysis. Thought you might be interested in seeing it – if so, drop me a line.

    Luke

    • Luke,

      I am interested in developing a spreadsheet/program that will analyze open web steel joists, and code check them to the Canadian Code, for in-house use at my consulting firm.

      I know all the necessary code checking, but not much about the programming. If you already have the joist analysis program done, you are already 90% there.

      Are you for hire?

      Mark Bettney

  2. [...] Frame Analysis with Excel – 5; Large frames in Excel 2003 Posted on March 5, 2009 by dougaj4 Continuing from: Frame Analysis with Excel – 4, 2AD frame analysis [...]

Leave a Reply