The Concrete Institute of Australia’s biennial conference is this year being held in Sydney from 8-11 September, and early-bird registration has now been extended to 15th July, so register now and save!
For more details of the conference see:
and for a lightning tour of Sydney and surrounds see:
Edit 3rd Jan 2026: As noted in the comments, as far as I know, the old versions of Adobe Reader are no longer available from Adobe, and the links given in this post no longer work.
The option to install a non-DC version of Adobe Reader used to be hidden away under a menu on the DC installation screen. It seems that Adobe would really, really like you to use the DC version, because the other options have been removed.
Non DC versions are still available though from this link. The link takes you first to a forum page, then directly on to the download page, but may take some time before the download box appears.
The link was provided at response No. 14 (thegeneticbytemare) at Where can I get Acrobat Reader without DC . That response also includes links to the latest upgrade and other language versions, but note that you have to install the full version before you can install an upgrade.
This post was prompted by a recent question at Fitting high order polynomials, asking for Excel methods to solve the equations for the radius of the Moon’s Lagrangian Point 1. All the methods described in this post have been added to the ItSolve Functions2 spreadsheet, which can be downloaded from:
The question asked for a solution to two equations:
The simplified equation may be easily solved by entering as a spreadsheet formula:
=O7*(O6/(3*O5))^(1/3)
The spreadsheet also includes a User Defined Function (UDF) called Eval, that will evaluate a formula entered as a text string, as shown below:
The Eval UDF returns the same result as the spreadsheet formula:
The simplest way to solve the more complex formula is to use the built in Goal Seek function (on the Data Tab), under What-if Analysis. To use Goal Seek first enter a guessed value for the radius, r, then enter a cell formula to evaluate the function:
(Me/(R+r)^2)+(Mm/r^2)-((Me/R^2)+r*(Me+Mm)/R^3)
as shown below:
Then call the Goal Seek function (Data – What-if analysis – Goal Seek):
Goal Seek will adjust the value in the selected changing cell (O15) so that the “set cell” (O18) evaluates to the selected value (0):
The Goal Seek function is built-in, and is the most convenient for a one-off solution, but it is slow and cumbersome to use for a large range of data. The UDFs QuadBrent and QuadBrentT are much quicker and more convenient to use on tabular data. The input for the QuadbrentT function is shown below:
Entering the function returns exactly the same result:
Finally the function may be rearranged as a quintic polynomial, that can be solved with the RPolyJT function:
RPolyJT returns all 5 solutions of the quintic polynomial as an array function, but in this case there is only one real solution, which is the first value in the results array.
More details of the UDFs described above can be found at:
Malinda Kathleen Reese mostly sings popular songs, after passing the lyrics through Google Translate multiple times.
But this is something else:
The RC Design Functions spreadsheet has been updated (to Version 8.04) with the addition of a CircU function for ULS design of circular reinforced concrete sections under combined bending and axial load. The new version, including full open-source code, may be downloaded from:
Typical input and output are shown in the screen-shots below:
Output of design moment capacity- axial load interaction diagram to AS 3600 with 40 MPa concrete:
The function has 3 options for the design concrete stress block: rectangular, bi-linear, and parabolic-linear. For the non-rectangular stress blocks the strain limits and parabolic curve exponent are set to Eurocode 2 requirements.
For 32 MPa concrete to the latest AS 3600 code the rectangular stress block is conservative:
With 50MPa concrete the conservatism is increased:
… but with 80 MPa concrete the rectangular stress block is significantly unconservative for mid-range axial loads:
Using the Eurocode 2 partial load factors and rectangular block width factors the rectangular stress block is slightly unconservative for all concrete grades:
Comparing rectangular stress block results for AS 3600, Eurocode 2, and ACI 318, for 32 and 50 MPa concrete the AS 3600 results are significantly more conservative for intermediate axial loads, and the Eurocode results are less conservative above the balance load:
For 80 MPa concrete the AS 3600 and Eurocode 2 results are close up to the balance axial load, with the ACI results being significantly less conservative except for very high axial loads:
Newton Excel Bach, not (just) an Excel Blog 