The design checker
What a design checker does
Section titled “What a design checker does”The design checker reviews the submitted design documentation professionally: the adequacy of the solutions, the correctness of the calculations, compliance with the regulations, and whether the documentation is complete and free of contradictions.
They do not redesign and they do not take over the designer’s liability — the review produces comments to which the designer has to respond.
When it is mandatory
Section titled “When it is mandatory”Legislation prescribes it within a defined range, tied to the significance of the structure or the works. That range changes from time to time, so check the text in force on a specific project.
When it pays even if not mandatory
Section titled “When it pays even if not mandatory”For a bespoke structure
Section titled “For a bespoke structure”Where there is no catalogue and every calculation is bespoke — a thin-walled steel frame, for example — a second pair of eyes is worth a lot. Not because the designer makes mistakes, but because assumptions slip easily in a complex model.
Where several designers work
Section titled “Where several designers work”Contradictions arising at the boundaries between disciplines can often only be spotted from outside.
Where the structure repeats in quantity
Section titled “Where the structure repeats in quantity”In a structure built in series, one mistake is multiplied. Here the cost of the review is a fraction of the risk.
What a good design check looks at
Section titled “What a good design check looks at”- The relationship between model and reality: the actions taken, the restraint conditions, the modelling of the bracing.
- The load path: whether the load can be traced from roof to foundation.
- The connections: most mistakes are here, not in sizing the members.
- Contradictions: the services drawings against the structural drawings.
- The completeness of the documentation: whether everything is there to build from.
What not to expect of them
Section titled “What not to expect of them”That they override the designer’s decisions on taste, or that they redesign the structure. A good design check looks for risk, not for an alternative solution.
The practical benefit
Section titled “The practical benefit”A design check works when it happens in time: before manufacture starts. A fault found at the drawing board is a few hours; the same fault after manufacture means members made, erection and time.
The point
Section titled “The point”A design check is not mistrust but risk management. Where a bespoke structure is being built, an independent review is the cheapest insurance.