Abstract

Coventry Cathedral was completed in the early 1960s and has some prestressed elements to resist lateral thrust from the roof. Other prestressed structures of a similar age have had corrosion problems and this has drawn attention to the fact that there is little publicly available information about the structural system at Coventry. This talk addresses that issue and is in three sections. The first summarises the four different prestressing systems in the cathedral and estimates the amount of prestress and its purpose in each location. It shows that the design was based entirely on lower-bound principles using very simple analysis techniques. Although there is no evidence of corrosion in the building at the moment, it is impossible to inspect the existing tendons, so the second section considers what might happen to the structure if corrosion of the tendons were to occur. It is concluded that very little warning of failure would be given, which would be especially important for the tendons over the Baptistry window and those in the Nave ties. The final section considers what could be monitored to give as much warning as possible about future problems. The effects of loss of an individual tendon, which would not by itself be sufficient to cause failure of the structure, would cause only very small strains that would be difficult to distinguish from the background strains caused by the temperature changes. Many of the principles discussed in the second and third sections would be applicable to most other prestressed concrete structures.