Following a comment here I have updated my RC Design Functions spreadsheet, which is available for free download (including full open-source code) from:

RC Design Functions7.zip

The main new features in the latest version are:

• The existing optional “depth” argument has been extended so that an array of reinforcement areas can be entered, which will override the values in the main section data input.
• My Goal Seek macro has been added, so that the reinforcement areas can be adjusted so that the tensile reinforcement stress, or section bending capacity, match a given value, and the process can be automated over a column of data of any length.
• Examples of using the Goal Seek macro with the EStress and UMom functions have been added.

The screen shots below show samples from the new examples.  Further details of setting up the data to work with the Goal Seek macro will be given in the next post.

Data input for the Goal Seek macro, in conjunction with the EStress function:

Similar input with the UMom function:

Reinforcement stresses, and section bending capacities, after adjusting the reinforcement area with Goal Seek: