I write to correct omissions in your recent article on our parapet research (NCE, 10 May).
Bridge engineers have been well aware of the potential risks associated with masonry parapets for many years. The challenge has been to develop methods of assessing the performance of this traditional form of construction.
Considerable progress was made as a result of an invaluable series of car impact tests organised by the County Surveyors' Society and carried out at the Motor Industries Research Association (MIRA) in 1993/4. Follow up work led to the production of Part 4 of BS6779.
Our research is being conducted in collaboration with Sheffield and Liverpool universities, where dynamic materials testing and finite element work are being carried out. Its aim is to build on the earlier work by enhancing our understanding of response mechanisms and developing new analytical approaches, both for plain masonry and for walls with retro-fit reinforcement.
The collaborative nature of the research and the background of the MIRA testing work and BS6779 were all fully explained to your reporter.
Indeed, the main photograph must have been obtained from MIRA, as it relates to their test work.
It is extremely unfortunate, therefore, that no credit was given to the earlier work or to our collaborators at Sheffield and Liverpool. The headline and opening paragraph are also inappropriate and are not quotations from me.
Our tests, far from 'raising fears', are aimed at providing engineers with new information and tools to aid them in assessing and managing any risks more reliably.
Professor B Hobbs, research & development department, University of Teesside, Middlesbrough, TS1 3BA