30 years to replace bridges

Taupo Times, Volume 23, Issue 54, 9 July 1974, Page 9

30 years to replace bridges

At present levels of progress it will take at least 30 years to replace all existing narrow bridges in the State highway system, according to a report presented at a meeting of the National Roads Board. The report, which covered progress on State highway and county bridging, expressed concern in the declining trend in bridge renewals. The board recommended the report be referred to all roading authorities through district roads councils. It also requested that the roads councils undertake an urgent review of bridging needs in all sectors with a view to producing an overall co-ordinated bridging programme for each district. In the State highway system there are 898 bridges of inadequate width totalling 122,804 feet (37,440 metres) in length. About 30 bridges or 4000 feet (1219 metres) are currently being built. At this rate the gap could only be closed in 30 years if the board limited itself solely to the replacement of existing narrow bridges. The report noted that there were at present 123 bridges in the State highway system which are

restricted for weight and/or speed. County bridging is in a similar position. The 1969 roading survey showed that* 1531 bridges would be required in the next five years. But bridge buildinghas been declining steadily. In 1963-64 332 county bridges totalling 18,374 feet (5601 metres) were built. Last year only 151 county bridges totalling 12,068 feet (*3670 metres) were constructed. The problem is not merely one of finance, since funds for bridging contracts have been consistently underspent, but rather one of design and contracting resources. The report suggested that roading authorities with large bridging programmes should seriously consider the establishment of their own bridge gangs to increase contractors' bridge building forces. Since the collapse of the Bulls bridge inspection procedures have been intensified, with particular reference to bridge foundations. The roads board recognises that river beds are constantly changing. The activities of man rhay accelerate or slow down change and bridges require a careful watch to ensure that adequate safety margins are maintained.