§ Dr. Owenasked the Secretary of State for Transport what progress has been made in discovering the extent of cracking and other damage caused by alkali-silica reaction in the two A38 flyovers immediately east of Marsh Mills roundabout in Plymouth; what is the nature and cost of any remedial action or repairs already known to be necessary; when the consultants hired by his Department, Mott Hay and Anderson, will make their initial report to the Department; whether a subsequent report is expected; if reports from the consultants will be made public; what is the extent of cracking or other damage caused by alkali-silica reaction on other bridges in Devon and Cornwall; and how long it is forecast that lane restrictions will apply on the two A38 flyovers at Marsh Mills.
§ Mr. Tom KingThe consultants' investigations into the damage caused to the flyovers east of Marsh Mills are proceeding satisfactorily. Their interim report has been delayed by the need to establish the path of the cracks within the concrete by ultrasonic and other non-destructive methods of testing. These are time-consuming and interpretation of the results complex, but the report is now expected within the next month or so. A further report will be provided next year. Copies of both reports will be made available to the public at cost on application to the Department.
No assessment can be made of the extent of the damage to the flyovers or the cost of repairing this until the consultants' report has been received and there has been opportunity to consider it.
83WAlkali aggregate reaction has also been identified in two more bridges on A38 at Plympton hill and Voss farm and the consultants' report will contain recommendations in relation to these structures in addition to the flyovers east of Marsh Mills. A further 11 trunk road bridges in Devon, built with similar materials, are potentially susceptible, but their present condition is satisfactory. No similar problems have been identified in Cornwall.
Although the lane restrictions on the flyovers at Marsh Mills are not causing traffic problems, the need for them will be reviewed when the consultants' interim report has been received.