BLACKBALL BRIDGE

Hokitika Guardian, 19 August 1926, Page 3

BLACKBALL BRIDGE

NO FAULTY WORKMANSHIP,

WELLINGTON, Aug. 17

Recently ..Mr 11. 10. Holland put a question in the 1 iou.se of Representatives regarding the Blackball Bridge, and asked that an enquiry should be made into alleged statements that a number of the piles hud been sawn off instead of being fully driven. Mr C. .J. McKenzie, of the Public Works Department, made the following report on the subject, which was read by the Minister (the Hon. Mr Williams) in the House to-day:—“l have made, full enquiries into this matter, and have searched our tiles dulling with the construction of this bridge, which took place 23 years ago. I am aware that some of the piles which were scoured out were shod us if seven or eight feet had been cut off the small end of the piles, this being disclosed by the marks on the piles. This shortening, however, was carried out with the full knowledge of the Engineer in charge of the works, who reported it by memorandum under date February 13th. 1903, to the then Kn-gineer-in-Chief. In this report he says that the driving was so hard that it was impossible to get the piles down to the specified depth. He describes the conditions of driving, and gives the length of the piles in the ground, and the final test blows.

“In order to show the difficulties experienced, I have taken the description of a tvpical pile, in flic first main pier, and give it to you exactly as reported at that date:—‘No. 1 pile, pitched at 24ft., drove 29ft. Gin. in the ground, or 40ft. Sin. below the cap, going Jin. to the last blow in the 10ft. drop and a two-ton monkey.’ Practically speaking, a test as. good as this indicates that a pile has been to all intents and purposes driven to refusal.

1B ?ho Engineer, continuing his report, states:—‘Where the piles specilied at 54ft. would not drive, they have been cut off at the small end to the depths as pitched.’ After the piers in question were washed out. new piles were driven by the Railway Department as far as possible to drive them deeper than the original piles. The fact, however, remains that so great is the scouring velocity of the river that those new piles, driven under very much better conditions, and under the mast careful supervision, were also scoured out hy the later floods of May 3rd. and May 12th.. 1926, and it is possible that cylinder sinking may have to he resorted to.”