Update 17 May 2022: Following discussion on 10-11 May 22 the download file has been updated to version 2.15, fixing problems with the interaction diagram with a rectangular stress block under high axial loads.
I have uploaded another update to the ULS Design Functions spreadsheet with some new features and fixes. The new version can be downloaded from:
The changes in the new version are:
- Stress block type 3 will now use the Eurocode full parabolic stress block.
- In previous versions entering a reinforcement yield stress of 600 MPa resulted in a divide by zero error. This has now been fixed.
- Using the AS 3600 rectangular stress block, there has been a minor correction to the calculation of section capacity when the neutral axis is at or beyond the “tension” face, so that linear interpolation is used, as required by the code.
The Eurocode parabolic stress block may be used with AS 3600 and AS 5100, as well as Eurocode 2:
Interaction diagrams to AS 3600 are shown below for the rectangular stress block (including 10% reduction in concrete stress for a non-rectangular section, the Eurocode parabolic-rectangular stress block, and the full parabolic stress block: