Phase 4 · Meet the Core Objectives

4. Analysis and Sizing

That you understand how structures actually behave, that you choose an analysis suited to the question, and that you know whether to believe the answer.

Who this is for:Candidates at any stage ·Mentors

Minimum standard: Ability for Incorporated-Member, Ability for Chartered Member.

Core Objective 4 — what IStructE says

Institution of Structural Engineers

This objective is intended to demonstrate an understanding of structural behaviour and the ability to assess behaviour using appropriate methods of analysis.
Minimum standard, Incorporated-Member: B — Ability. Perform the subject without supervision and be competent to advise others.
Minimum standard, Chartered Member: B — Ability. Perform the subject without supervision and be competent to advise others.

From IPD Guidance — Chartered Member, Institution of Structural Engineers.

What strong and weak evidence look like

Worth doing

A hand calculation you used to check a computer model, and what it told you.
A moment when the software output was wrong or misleading, and how you found out.
A stated justification for the analysis method — why this model, at this level of refinement.
The assumption the answer turned out to be most sensitive to, and what you did about it.
Sizing you carried out, with the criterion that governed and by how much.

Avoid

Output from a package, presented as the engineering.
"The model was verified by the software."
An analysis with no statement of boundary conditions or idealisation.
Not knowing whether strength, stiffness or something else governed your own design.

Portfolio items that tend to work here

A calculation extract showing the judgement, not twelve pages of output.
A hand check set against a model result.
A sketch of the analytical model with its idealisations annotated.
Evidence of a sensitivity check or a comparison against a known case.

4 items · saved in this browser only

Suggestions, not a required list. What matters is that the item is yours, that it is annotated, and that it demonstrates the standard rather than the subject.

Questions to ask yourself

How did I know my answer was right?
Checking is where engineering judgement lives, and it is the question that most reliably separates people who did the work from people who ran the software.
What does my model not represent?
Every model is an idealisation. Being able to name what has been left out is the point.
What governed, and by how much?
Not knowing suggests the design was produced rather than understood.

The same objective, in different kinds of work

Illustrative. The objectives are written to be met in a range of ways by anyone practising as a structural engineer.
Setting	What the evidence tends to look like
Design office	Justifying that a simpler analysis was adequate, and proving it with a check.
Assessment	Deciding how much of the real behaviour the code method fails to capture, and what to do about it.
Temporary works	Working out the load path in a condition nobody has drawn, and checking it by hand.

Illustrative. The objectives are written to be met in a range of ways by anyone practising as a structural engineer.

How reviewers tend to approach this objective

Taking a calculation from your portfolio and asking you to talk through it from first principles.
Asking what you would expect the answer to be before running anything.
Asking how you would check a result you had no independent means of verifying.
Asking what happens if a stiffness or a support assumption is wrong.

There is a bank of original practice questions in the interview question bank, filterable by objective and by grade.