Release: Adrian Cowie
Media Release 24 November 2016
Structural Engineers Potentially Compromising Life-Safety in Wellington Building Assessments
Christchurch Registered Professional Surveyor, Adrian Cowie, has expressed concern that structural engineering societies may be potentially compromising the life-safety of tenants in medium-to-high-rise buildings in Wellington by advising its structural engineering membership to carry out accurate survey monitoring – practically always done by specialist measurement surveyors and not structural engineers.
On Monday 21 November 2016, the New Zealand Society for Earthquake Engineering Inc. (NZSEE), Structural Engineering Society New Zealand Inc. (SESOC), and New Zealand Geotechnical Society Inc. (NZGS) sent an information email to their members titled:
“Kaikoura Earthquake Sequence: - Building Assessments in Wellington and Access to Information” ( Web Version here )
This information encouraged structural engineers to carry out accurate measurement and measurement monitoring of damaged buildings. Structural engineers are typically not trained in the accurate methods of measurement, error mitigation, and repeatability of measurement, areas that are within the expertise of Registered Professional Surveyors.
Adrian Cowie, who has had extensive experience in the monitoring and surveying of earthquake damaged buildings in Christchurch post 4th September 2010, including a number of the Christchurch high-rises, has expressed concern that structural engineers, if they followed the above email, would be working outside their areas of expertise.
Mr Cowie stated:
“The measurement and monitoring of earthquake damaged buildings requires a very high level of expertise in surveying and measurement science which is likely outside the expertise of most structural engineers. The accuracy and repeatability of measurements is crucial and something that is within the expertise of most Registered Professional Surveyors. Structural engineers typically do not have the proper instrumentation, proper training, or proper methodology for taking accurate, dependable, and repeatable measurements.”
He went on to state:
“It appears that these engineering societies have forgotten that New Zealand has a specialist university degree course, the Bachelor of Surveying (a four year course that trains surveyors in the art and science of measurement, error minimisation and the methods for the repeated monitoring of structures) and that to obtain the title Registered Professional Surveyor requires a minimum 7-8 years of education, training and examinations.”
The NZSEE, SESOC and NZGS information email to its members included the following advice:
“Noting that there may be future significant aftershocks, it may also be worthwhile to consider future monitoring:
Set up control points on the faces of columns and record accurate benchmark measurements that can be easily accessed and compared (to assess beam elongation).
Measure and record crack widths in floor slabs using a crack gauge or tell-tails if available (to assess possible seating loss). Take care to mark where you have recorded the cracks so that you can find the same locations easily in future inspections.” [bold added to emphasis areas of surveying]
These suggestions are concerning as they clearly promote structural engineers to carry out accurate survey monitoring.
The specialist equipment that surveying experts possess is typically not owned by structural engineers, and includes precise instruments that can quite quickly measure and scan an entire structure, down to taking measurements of individual cracks to the nearest 0.1mm.
Surveyors have the equipment and software that can monitor structure movement, and provide accurate, dependable results.
A Registered Professional Surveyor can determine building tilt, twist, bulging, and elongation with their instrumentation, something that a Structural Engineer is unlikely to be able to do with limited equipment.
Structural Engineers typically only have limited equipment at their disposal which restricts both the measurements they can take, and the accuracy of those measurements.
Adrian Cowie approached the NZSEE and SESOC to express his concern regarding their suggestion to members to carry out accurate survey monitoring and requested they withdraw their advice. The response from the President of the NZSEE, Peter Smith, to senior members of the NZSEE and SESOC was:
“I suggest we ignore this email.”
This refusal to acknowledge the limitation in their own expertise, and the intention to ignore the expertise of other professions is worrying. It clearly demonstrates that even the most senior of New Zealand’s structural engineers may not understand the expertise that precise measurement entails.
The life-safety risk of building tenants has been clearly demonstrated in Christchurch. The CTV building collapsed with apparently no survey measurements taken on it, yet with extremely clear indicators that the geometry of the building structure had been severely compromised.
Structural Engineers need to understand the limits of their expertise, and also understand the expertise that kindred professions possess – and make appropriate use of these other professions.
Adrian Cowie provides the following advice to building tenants in the Wellington region: 1. Do not assume the structural engineer assessing the building is an expert in assessing earthquake damage. Insist on obtaining their qualifications, CPEng area of expertise, and their experience in this area of work.
2. Obtain a copy of their brief and scope of work from their client (presumably the building owner). They may have been instructed to carry out work totally different than what the tenants are expecting they are doing.
3. Insist on the proper experts working in their respective fields, for example, structural engineers in structural engineering, registered professional surveyors for measurement, surveying and monitoring.
4. Do not assume anything. If in doubt, request a ‘Stakeholder Consultation’ with the engineer to determine their brief, instructions, expertise, and standards they are working to.
5. Ensure the person taking accurate measurements is a qualified surveyor, for example, is a Registered Professional Surveyor.
The clear lack of understanding of surveying, measurement and monitoring by NZSEE and SESOC raises some serious concerns that little has been learnt from the building collapses in the 22 February 2011 earthquake in Christchurch.
24th November 2016.
Adrian Cowie has worked closely, and continues to work closely with Structural Engineers in the assessment of earthquake damage to buildings and structures, including the design and implementation of monitoring surveys to determine the magnitude and extent of additional earthquake induced movement to structures.