Awahuri Bridge in Advanced Decay

Manawatu Times, Volume LIV, Issue 7284, 11 October 1933, Page 4

Awahuri Bridge in Advanced Decay

A special report on tho condition of the bridge over the Oroua river at Awahuri, presented to the Kairanga County Council yesterday by the aot-iug-enginoer (Mr L. C. Pickering), revealed that tho structure was in an advanced state of decay.

The remaining wooden portion ot' this bridge was constructed in 11597 of local timbers, namely black mairo and totara, probably cut .from trees in .the vicinity of the present structure, and from inspection conveys tho idea that the timbers were not of tho best procurable, for in many instances bridges built 20 years previous to the erection of this bridge are to-day in much bettor condition than the timber in the Awahuri bridge. Tho important members of tho structure arc in an advanced state of decay, and the bridge on the whole is not safe for hcavj trafric.

The main weakness lies in the bottom chord and thrust blocks, partly through neglect during tho carlici stages of its life in not receiving periodical attention at the joints. The causes of decay aro dry and wet rot. The former, which at first appearance is not discernible owing to tho preserved state of the outer shell, was only discovered by boring tests, and this revealed extensive decay in many members. Urgent renewals have been carried out in the public safety, although the quantity of timber used in renewals is not great. The expense lies in supporting the whole truss while repairs aro being effected. Difficulty was experienced in' withdrawing corroded bolts and boring and fitting new bolts through powdered timbers which constantly seized the drills.

The cause of so many joists being fractured and springing was tho fact that the joints in the decking were not “broken.” All decking has now been lifted, relaid and joints “broken. ” This will distribute the weight more evenly over a greater number of joists, and. should overcome any further trouble from this source.

Although a careful examination of all timber has been carried out it must be borne iu mind that still further defects other than, those stated would probably be revealed if extensive repairs were carried out, owing to their being now partly concealed and difficult to examino at the present time. Knowing the condition of the bridge, the minimum amount to replace all.deeayed timbers, allowing for staging, ironwork and timbers, would be in the vicinity of £2500.

The engineer reported that the repairs undertaken would last for IS months.

Tho chairman observed that thero was nothing for it but a new bridge, and when framing next year’s estimates the council would have to give consideration to the proposal. Cr. Anderson: Wo will just have to hold it up till tho Highways Board can give us a new concrete bridge. The engineer was congratulated on his comprehensive report.