DAMAGE TO BRIDGES AND CULVERTS

Dominion, Volume 31, Issue 204, 26 May 1938, Page 15

DAMAGE TO BRIDGES AND CULVERTS

Council Examines Causes

INSUFFICIENT. WATERWAY AND SHORT SPANS

Dominion Special Service.

Napier, May 27

Causes of the heavy losses of bridges and culverts in the Hawke’s Bay County Council’s district during the Anzac Day flood, and how best, to prevent similar damage in future, were discussed at the first meeting of the new council to-day. Councillors also reviewed the extensive damage to roads, as well as urgent traffic problems arising from flood conditions. During the discussion councillors agreed that all the resources of the county should in the meantime be concentrated on giving access to those settlers who were still unable to get out. The chairman, Mr. C. C. Smith, said the council's aim was to give access to those who needed it, and the council’s staff was using every effort to attain that end. Slips' were so serious that removal by old hand methods was out of the question, and the council would have to consider the purchase of a bulldozer or other mechanical contrivance to remove the slips before wet weather set in, in which case further serious damage would result.

Councillors were generally of _ r -he opinion that the huge losses of bridges and culverts were caused by the long period of comparatively dry seasons encouraging a policy of building bridges aud culverts having insufficient waterway. A motion was carried unanimously directing the engineer when preparing plans of bridges and culverts in future to provide the largest possible waterway. Councillors emphasised that the present county engineer, Mr. R. Puflett, was not responsible for the designing of many bridges which were carried away; many of these were designed and built by the Public Works Department, and afterward taken over by the county. When the engineer presented reports showing that replacing and repairing the bridges and culverts alone would cost up to £30,000. and repair of roads almost a similar sum, Cr. C. Lassen said it was evident that in the past the waterway allowed was insufficient. It appeared that extra lengths would have to be provided in future. Run of Dry Seasons. ‘'The long period of comparatively dry seasons encouraged a policy of building short bridges and restricted culverts,'’ said Cr. R. Harding. He agreed with Cr. Lassen that longer bridges and bigger culverts would have to be provided. Cr. 11. E. Crosse said in his opinion the spans were too short, causing piling up of timber and other debris against piers. Cr. F. K. Wilkie said the question was purely one for engineers. If the bridge openings were too small in the past, bridges would have to be designed to suit the flow of water. Cr. J. McDonald said he supported Cr. Harding’s contention that a long succession of dry seasons was responsible for the bridge-building policy. He considered all bridges should be built to cope with extraordinary rainfall. In reply to Cr. Harding, the engineer. Mr. Puflett, said the lengthening of abutments was not a particularly costly business in level country, but in hill country the extra cost would be very heavy. Cr. IV. Tucker said bridges would have to be lengthened. Spans Too Short. “The existing spans arc undoubtedly too short,’’ said the chairman. The Esk and Waipunga bridges were both shortspan structures, and both were carried away. During the February flood he saw a sixty-foot tree stretched across four spans of the Esk bridge. Pressure on the piers must have beeu very great. The new bridge over the Esk River being built by the Public Works Department would be much longer and higher than the previous bridge, and would have fewer spans. . Cr. 8. L. Palmer said it should not go out that the county engineer was responsible for the way in which the bridges had been constructed. Many concrete bridges which were unsatisfactory had been taken over from the Public Works Department, which had built them. Cr. Harding said the flood was the worst for 30 years. He emphasised the necessity for building for a maximum flood, not for an average flood. The urgency of early construction of a new Pakowhai bridge and improvements of the road through Poplar Grove wn.s stressed earlier in the meeting , by both Crs. Harding and Lassen. They pointed out that the closing of the Pnkowhai Road for nearly a month following the flood caused great loss and inconvenience through all traffic having to use the longer Fernhill route. Cr. Lassen moved that the engineer prepare an estimate of the cost of raising the road through Poplar Grove above flood level. The motion was seconded by the chairman, who agreed that the present road level was too low, Cr. AV. Tucker said the road between the bridges and the Fnrndon turn-off should now be built over file silt, which was several feet deep. He emphasised that this road would be in use at least two years before the bridge was completed. Cr. Lassen’s motion was carried unanimously. Fernhilt Bridge. Cr. Lassen also drew attention to apparent inconsistencies regarding the use of Fernhill bridge by heavy traffic. He said he had seen heavily-laden lorries travelling over the bridge two at a time, and at speeds he thought excessive. On the other hand other lerries apparently no more heavily laden were turned back. Cr. E. H. Beamish said since the flood the bridge had been asked to carry ten times the volume of traffic it had before the flood. There seemed to be some doubt in thesminds of many carriers regarding the loads they were allowed to carry over the bridge. The fact that the Pnkowhni Road was ouen for traffic should be made more widely known. Cr. Harding agreed with Or. Beamish that the position concerning loads should be clarified, and the council decided i-J erect notice's at each end of the bridge setting out the maximum load and speed.