Skip to main content

CROSS Safety Report

Architect conducts structural design of sway frame for domestic project

Report ID: 678 Published: 1 April 2018 Region: CROSS-UK

This report is over 2 years old

Please be aware that it might contain information that is no longer up to date. We keep all reports available for historic reference and as learning aids.

Overview

A reporter looked at a project recently where the drawings had been produced by the architect, including a structural design.

Key Learning Outcomes

For all built environment professionals:

  • It is important to recognise and know the boundaries of your expertise and work within the limits of your competence

Full Report

Find out more about the Full Report

The Full Report below has been submitted to CROSS and describes the reporter’s experience. The text has been edited for clarity and to ensure anonymity and confidentiality by removing any identifiable details. If you would like to know more about our secure reporting process or submit a report yourself, please visit the reporting to CROSS-UK page.

 

A reporter looked at a project recently where the drawings had been produced by the architect, including a structural design. This showed a steel frame within a gable wall to create a new 5.2m wide opening using two No. 152x89 universal beam (UB) posts per end with a 203x102UB supporting the inner leaf and 178UB supporting the outer leaf (but both beneath the floor/new lean-to roof).

There was a note to say that the beams were designed as fully restrained. The method of restraint turned out to be with proprietary galvanised mild steel straps at 800mm centres. The reporter considered that the beams should be 2 No. 203x133x30UBs minimum as the lateral restraint was inadequate. Also, the foundations for the posts were inadequate.

The reporter knows of quite a few architects who do this. They apparently use online programmes to do the design and just submit the calculations which include disclaimers at the bottom of each sheet. They cannot understand why building control pass them and why the Institution of Structural Engineers (IStructE) are not doing more to prevent it? He wants to know what he should do about this?

Expert Panel Comments

Find out more about the Expert Panels

Expert Panels comment on the reports we receive. They use their experience to help you understand what can be learned from the reports. If you would like to know more, please visit the CROSS-UK Expert Panels page.

Restraints are only as good as the component stiffness to which the restraints are added. SCI Publication P360 Stability of Steel Beams and Columns provides guidance on the determination of buckling resistance of beams and columns. There is a tendency amongst some to think that small structures are not worthy of ‘proper design’, but any number of failures show this to be untrue.

In the case reported here, it is possible to envisage excessive beam deflection, beam twist under eccentric loading, falling of masonry post buckling, global side sway of the frame in or out of plane, and so on. Unfortunately, as we all know, building control have finite resources, and this presents real risk. CROSS have made their opinions known to the current consultation on building regulation and its enforcement.

A few years ago, a court in Italy fined a software house for claiming that their programmes could design seismically resistant buildings. Unqualified persons, including architects, should not design structures, although there is nothing about this in the building regulations. It is a basic principle that those who are registered professionals know the boundaries of their expertise and constrain themselves to work within their limits of competence.

It is not uncommon for architects (and surveyors) to undertake structural design on what they consider to be minor elements of a building, but without sufficient training to properly understand the concepts. In addition, they rarely have any appreciation of the dangers their lack of knowledge can cause. The matter will be raised with the Royal Institute of British Architects (RIBA).

Submit a report

Your report will make a difference. It will help to create positive change and improve safety.

Our secure and confidential safety reporting system gives professionals the opportunity to share their experiences to help others.