The Brohn Method

A method for the development of a sound, reliable and effective basis of an understanding of structural behaviour. The Brohn Method is based on the testing of three consecutive years’ entry to the Arup Graduate School in the early 1970’s.

Their performance in a test was much less than expected, with a mean score of 35%. Arup then commissioned David Brohn to develop a two-day training course to correct this deficiency.

This course, ‘Developing an Understanding of Structural Behaviour’ has been run continuously since that time for many of the UK and Europe’s structural consultancies.

The significance of the test results was finally recognised by the Institution of Structural Engineers in 2009 who set up a committee to promote the development of this skill in UK Universities. However, in what is a familiar outcome of committees, that objective was lost and what was a once in a generation opportunity to ensure that graduates had a basic understanding, was lost.

The failure of the academic community, with rare exceptions, to develop this skill is not all that surprising; it requires a sound and reliable understanding that can only be achieved with practice that does not fit well into the traditional syllabus.

But the overriding reason for the graduate’s failure is that the reasoning required is not the ability to solve the typical approach in structural analysis; identify the algorithm and solve a linear sequence, but a sound understanding that relies upon a cyclic approach.

Because this skill is so critical in the design process, we have decided to establish a Certification for The Brohn Method.

The key aspects of The Brohn Method

The method is deceptively simple. After all, graduates know what deflected shape and bending moments mean. But as demonstrated in David’s research, they consistently fail in the test.

The explanation for the failure is that it has not been explained to them that the solution must consist of the three parts to the solution. The reason for this is that it is very easy to arrive at an incorrect solution, and it is only by applying the checking procedures with the other two parts of the solution that the error is revealed.

It is for this reason that testing only one part, as in the IStructE Test, does not confirm that those tested have a sound understanding of structural behaviour.

Certification of The Brohn Method

This is aimed at graduates with more than three year’s design office experience who have already focussed on the development of this method, either by studying the text, ‘Understanding Structural Analysis’, available from bookshops and Amazon, or by attendance at the CPD training course, run either internally by the IStructE CPD program, or the online course.

The certificate will be awarded on completion of an online test, which will require the candidate to show the full three-part solution and what internal checks were carried out.

This will be a difficult test, with a pass mark of 70% and a distinction over 90%. Once you have signed up, there is no limit to the number of times you can attempt the test, but that number will be noted on the certificate.

A typical Test Question

This frame is statically determinate, but 90 % of all graduates tested over several decades produce the incorrect solution. By applying the other two parts, it is immediately apparent what the correct solution should be.

Test Item

Typical incorrect solution

Most obvious check

Correct solution