WARNING TO LOCAL BODIES.

Manawatu Herald, Volume II, Issue 274, 26 June 1889, Page 2

WARNING TO LOCAL BODIES.

JjTjQYJ} ; y^.MANAWATDr RoAD BoABD The claim was for £134 for in juries sustained by plaintiff through the giving way of a bridge in the road district. After a lengthy hearing the eaae has been decided by the plaintiff gaining a verdict for £120 and costs, amounting to £22 ss. As the whole ease rested on the question as to the strength of the bridge, we have reproduced the evidence of Mr P. H Rawson, assistant engineer to the Pub ie Works Department, and from that it appears evident that very few of our local bridges are of the strength deemed necessary. He stated that a bridge, having a span of 3ft 7in between the stringers, and totara decking 6in by Bin, would, according to formula of the department, oarry a safe working load of 900lbs; The actual bratkiagt

weight would be nine times that weight. With spans of 3ft 7io, 6in planking, to cany a safe load of one ton per wheel, should be five inches deep. To cany 1£ tons on each wheel, the planks should be 6in x Gin. An Bin planking to bear a ton should be 4in deep, and to bear l£ tons, sin deep. For an ordinary district road would put totara plankiag, Sin or 9in x Sin on a bridgo witb 3ft 9in spans. The fact of the decking being down for 8 or 10 years and beipg. worn away a quarter of an inch would make a difference of 10 or 15ft per cent, in the beano* power of the timber. Qravat, weighed about 1£ tons per yard; a a fair load would be about a yard. - A fair load on a four-wheeled waggon was, he would say, about 2000 {get. In constructing bridges on. by-roads, would consider first whether or not threshing engines were likely to go Acrosi them. Considered in a bridge of 8f fc 7in spans, 6in x 3in planking, thti?e wag not sufficient margin for safety for .a threshing engine passing ant it. A threshing engine weighed on the average about eight tons. Produced two typical road Dridges designed lby the Public Works Department. H» had taken designs showing theweakest end the st ongest of standard;: works.- Thid weakest bridge-had 3ft v * lin spans, and Bin x 4in planking, v and the strongest lft 7f in spans and Bin x 4in planking. Of 3ft 7in spans it would be necessary, on thff weakest of bridges constructed by the Department, to put Bin by sin planking,