THE PETONE WHARF.

Dominion, Volume 3, Issue 647, 26 October 1909, Page 6

THE PETONE WHARF.

inquiry into its' subsidence. . , ; ; 'the pi^driv-ing.;"" ; 'The''inquiry'into.' the; subsidence '.of, ..the V re-, ccntly-ere'ct'ed wharf at Petbh'e was continued before tho. .Harbour. Board yesterday, .afternoon; ' Mr. i.T. ; M. "VVilford,: occupied: the chair, anil, there were Hon. T.'.K.'Mac. ilohald, Messrs. J l . W. M^Ewan,'; E.' Fletcher, J.:..G.'. HarkneW.me'mbers cf,. the. 'board,'; Mr. J. Jfarohbanks (engineer); .and Mr. H. E.. Nichi Oils .{secretary)...'y-;-;;:-. ■ ~:.;y.:: At the outset'Mri; Macdonald said he thought a mistake .had; been made- in commencing the. inquiry, in cb'mmitteel'.He moved:that the proceedings should be open to the" press.; The motion was seconded by Mr. Fletcher, supported by and carried. .' ■ William Gardiner; a member of the firm of Messrs. Wm.: M'Lean and C 0.,: contractors- for the wharf, said.he hail .noticed the' men.driving a'-.pile,'-and' in his opinion the'driving seemed to "be going too" easily;'- A two-ton was being used. When, it was seen that the driving was too easy ; the' work was stopped; and they ■waited until the matter- was reported to ,the authorities in Wellington. A second pile was driven,' and it also, went' in-too easily.' Next morning- the. clerk, of works (Mr." Thornton) told the men to go. on.as the engineer, had though, that,the -suction of. the piles', would make the driving stiffer later, on.. He/understood there was something in the suction theory, but did not hold.that.belief now. He thought' the' pile-driving might.have encountered quick-, sand. '.- .'■•',. ■■•■V'"■";'.■;,■ '.-.'■ "'■ .".' .■' ', The chairman: Do.you-think ifz-borings had been,.taken thisj isubsidehce ;could have been prevented? ...-''' ', . .'"■.- Witness: Probably it could.■':.'. . '/..'■ ;'". . .The chairman': •. Was it. possible; .to :ascertain : the condition, of, the bottom 'without /borings? Witness did hot-know; but he would consider it-necessary to toko borings." .If borings-had been' taken it. would,' he. thought, have disclosed' the conditions at the site; of/the wharf. It ,was' proved that:the piles, were hot 'sum--cientlv long' in .thislease. :'■.'; '. Robt. C. J." Thornton said.lhe-was clerk .of works for 'the board at, Hie Petone. Wharf. In his opinion the piles at .Petone were • driven in accordance with the specifications, at the discretion of the'engineer. •When-'he: noticed that'the piles were going down much -top finely,he'reported 'the';matter'.'to' the contractor's chief inspector, and both 'of-them- mentibhed the fact'to Mr. Ca'cheraailk. That was about • June l:.this;year. As the result of an. inspection >'an.'order "was given, for. the use of. longer : piles in,' the "outeiv- rows. The, extra, ■lengths ;rahged from lft./-to 12ft; /, Though. an. oxtrnlength'''was'p'ut in,:no solid bottom.was found, and witness reported ..the 'fact' to' Mr. Powell, He'siiw the acting-engineer oh: 1 May 29i''.irhb sa'id'he did pot think/thc longer piles. would be''any'better: : . Witness allowed the work/to-'go-'ori, /'under ii>sh'-iiH;a"s" from his chief,.-Mr. Powell.;, He- thought- tlftt. fiu'cl.'-'. might-serve ; to'consolidate ii ime.' lie did notknow whether Kdrihg''would have r been useful in: the present/case. : s : ' ■'■"'■ •' -.To Mr.-Eletch'erV He started.supervising the driving : on May. 18,-1903. 'The wharf was designed to carry : a/loan jof-90:tons;.-but-a load of 200- tons of. timber;' had been placed' on /it in a'confihod space;' ar.d. that'night -a heavy soutberlj-'camo "up':' ; ln his' opinion -that was the cause of.thP trouble with the wharf..During the time, the wharf was being-built- tho contractors had-50-or 60 tons.on.a more confined space, but fib damage was' dono.-' ,' ■. ' Mr. !M: M'Ewarii. -He understood tha^r; the wharf '.was originally-'intended ■■■. for,, a, ferry, .wharf; and he. thought .it. would-.have; been ■strong enough for the purpose for which-it was designed.- One pile was driven 37 feet intothe ground, and gave no better results than others except for the' suction- of. the additional ground. '■'■ Mr. "T."S. Powell, inspector of...works, said that Mr; Thcrntoh was clerk of works in cpnhbctioh'with thedrivingbf'tho piles. He went but' occasionally:', to i-see-tp'. piles driven. - The clerk of:works: was 'responsible fori the driving of'the piles, and if they were'being driven'un-, satisfactorily, he, would report to. witness.'-.'. • t The chairman.' Did he? ;■•■"■'■-' . ■■• Witness: He said that the driving was soft. , , Continuing, he said a report was made to the acting^ngineer,.but orders " were'...afterwards given to go. on iwitk the. work.' .He"; knew that certain piles sunk a .foot t» every-two drops of the monkey.. He did not like the look of-that, •and' reported it to the acting-engiheer, who told him to go on with the work;- The engineer thought that as it'was a light structure it would hold, and that the sand would gather round the piles. In his opinion, boring wpuld have proved if 'the ground, was l soft or; not ; The Hon. T. K. wcrk?—l did. " ;"■'-',""• ■'- .*■'-,.'"/.''- ■/, l; ' Ana yoii, vieii ordered'to gb on; ; next,aaT by the'acting-engiheer?—Tes, ;;;"; . '|l, '."J,'- '' Mr." Cachemaille, of:,,the 'Harbour Board, said l .the plans, and specifications of the Petone-wharf were preparedlby Mr.'Wm. Ferguson, arid he took over,the cbnstructipn of the wharf-at the end-of February, 1908., . '..- /The chairman: Both' Mr. Thornton and Mr. Powell have stated. that -the pile-driving.-was •hot-satisfaotory.: Did, yoii-know;,that? ■.••'."■■■. .•.i'Witndss'-'said , that,-Mr.; Powell ■ - repprted to him' that the driving'was soft pri' a certain Saturday, but hot get out that'day. On the Monday he went but and observed. the driving. .-'•. He thought the driving was'suificiently firm, .and ordered' the work to /'go. on. He did not consult ■ the consulting, engineer .about the pile-driving. He was not avare that. the\last sixty piles were •driven.at of two drops .to the foot. • The drop that.'must be taken,into consideration. He did not-think boring would have shown the' condition—he would much prefer' to drive a' trial pile.-. It was cheapeffand infinitely more 'effect .tive./ '• .'.'■'.,■■■/■ -':* - ' ,; .■'..,. . : ':.':"-'.' ..." /'.'Mr: Fletcher: Do ybu-take the responsibility ~'of the construction, of .-.this; structure?-■.,.';;

Witness: Yes, I do.. ■'.',' '■■■■' ;Mr: Fletoher: W.eT6'--yoTi : 'not aware that the .driving.was'not,at all.satisfactory after.getting, the report of-Messrs. .Thornton .'and' Powell ? - Witness said, it'sas afterHhat,he had made the experiment of driving', an extra 'pile. ;""-...: : Why did not', consider it'- necessary." ■'."-. Mr'.'M'Ewan: In, the.faoe' of the reports of ypui; officers,', do you n.ot.think Vou would have shown wisdom in trying to reach Bolid; ground' —-I "did, with a.longer pile,-but could not.find the'solli''.";.-.' : '-. ■■"''■",: ..'.",'■,'.'■'-■,•;: '•'■.' : v - i ,/Do you not think -it- would have, been better to have -consuljed- Mr..;;Ferguson?—lt would have been better to'have consulted. hinv.at;the first'' -I..have' ; talked' with' him. about'it j whether it; wasat-' the'' time .of. 'the drivingor .after I. could, not'say.-''; ',:;■ : '• -j '■'..-''. ••'.'., ,: :"' : What .weight'was the wharf to carry?— About 3cwt. to/the/square foot;, that-is usually the capacity of the suburban wharves.) .-;. ,:.;',' Mr. MTBwan,'.':in making .'a : statement,.'.said from informatiori'"received, 'and'from his .ownobservation, he had reported the/mattor ofthe pile-driving ■ to:. Mr.' Cachemaille, and his answers-were, to .the -same .eifect' as. he had stated in his evidence..;■:. ' ■■;■ .-, v ._. : Mr. Fletcher said'that he thought, the M ln 'r ster for^Mines,should'be asked to.direct the Director of! Geological - Survey- to .rnike an ex-, aminationof the ground in the vicinity of the" wharf. Captain King had also intimated his willingness'to give, evidence. The question he wished to ask .Captain'lKing particularly was' as to whether he had made a statement to Mr. Ferguson.about the trouble the Gear' Company had experienced with its wharf.. ; : It was '(decided to ; communicate ;.with the /Director; of Geological Survey, and to obtarn-'a • statement from Captain' King, particularly in "reference to Mr.'Fletcher's'question.. "'■„,•■';:'' , • , The meeting. then adjourned until Monday ■ fortnight,:.' / ','.'•'■.;.. '';,':.■'.■-;--':'.'.':;..':"- '

;.;■■-. .ME: ; FEEGUSON'S''EVipENCB.;.;- '; ; At the' conclnßion' of the above meeting ,a. £opy .of Mr. William,- •Ferguson's... evidence (taken in committee on' October 18) was handed to.'-the'jpress. : '":'■'•-'■;■■:;•■ :;; '''/''.. ■■-.'•:'-. ■"■;..■ ;Mr. . Ferguson; stated, that: there were no boring operations: undertaken by himself .or, anyone' else at ketone.: He' did not think it necessary; because :a wharf'had been erected at practically r the sanie.site, of which h'e. had' a practical. knowledge- -The .beach was of shingle, aid piles 'driven in eleven or twelve feet were, in his opinion; sufficient, :-..••-■•.,' ' . • 'The Chairmanv Are-ybii, aware ; that,in the borings whioh have- taken .place recently' under the-direction of Mr.'Maxchbahks it;has been found 'that'..it is ..necessary to, sink 0. pile -to depths of 47,- lb', 46, and 57 feet before a.solid bottom can be'obtained?, . ... . yr, :■-:■:;' .. ~■ Witness: I am not aware of that It entirely depends oa'w.hat is meant, by.solid bottom. ■'. Many, structures are carried, on. shingle bed without -piercing the shingle. -..',' ■••■•: ! Witness, in ; answer, to questions, said that ' there had never been/.any.borihg.'in connection with the erection'of any of the ;ivharves. round the quay in Wellington. He had not-heard of any comment as to-'.the, subsidence-at Petone; had he been aware of it he would have- called Mr. Cacliemaille's attention .to it., Ho hod left the board's employ before the pilo-driving commenced, and; had -never beon' on the "structure since..' .■.;•'" v„,; ,:■'■- ■'"■■'""■? •'■', ''"'• I. The Chairman: What,was,the cause,,in your opinion, of tho subsidence? ;v: '■"•,' ■ Witness: I should fancy they, came on quicksand. I should say. that the artesian, water from the Hutt : River .was .coming ,up" there and causing a quicksand.V, - ; rf : '";• ,' To Mr. Fletcher:'Canyou.tell'u6 what steps, if any, were taken to know; whether this<,wasa suitable site?, . '■>•. ' '" ■.''■■•;'■' •■<.-, 7" '■ Witness: It'.was. necessary- to pat the ;wh»ri

in that portion of the beach because, of the protection afforded by Somes Island. We had the experience that a-wharf had stood theire for many years without any reported subsidence. The direction cf. the whan was fixed after consultation with' Captain King, of the Gear Meat, Company,'and Captain Johnson,, harbourmaster'.' '• , Were any'steps taken to'ascertain whether tho : ground v?as suitable for the erection of a striicturo"there?—None \sfiva necessary, in my opinion, because we "had" the experience of tho, previous wharf. . .. > ~ ■■ \ Do. you:see how necessary it is now?— One ib always ; wise'after the: event. ' . - ... •'.' ' Doyou not think'it was a strange course to prqeeedas yoii did without taking borings?— Not.'in the case/of a wharf on a shingle fore-; shore such as that is. I'am of.opinion thata wharf could be constructed on most shingle foreshore's' without "any ' necessity for borings, and in this case the wharf would have been structurally safe had it not'been'that; you came on-'a quicksand'which could riot have been foreseen.: .-...■■, .-■'•

Can you tell us what your expenenco was.iu this part of the foreshore, ot Petone?—The oxperien<» gained by the Gear Meat Company in extending its work during the time I was engi--neer to the board) ■:•.'' ' . To Mr. MTiwan: If four bonngs were taken at different points near the end of the wharf, arid those borir.gs disclosed the fact that there was a laver of ten or twelve feet of fine sand and. under tk:\t 30ft.'.or, nio're of soft mud,: would you still say that a quicksand caused the subsidence of the .wharf?—l think thiit what is called mud is a proof of quicksand. •What is. your opinion of, the borings shown on the recent plan?—l would have to ask how the- borings were carried out, because in the boring you. could so churn the material up that:it came out as a-mud.- There is'no.doubt that, had borings shown mud suchas is there represented, we would have adopted, some other, form of construction. '~:..■ If.'a member'of the board.during";the time the-wharf,:was. in course of construction came to. you as engineer, of the .board, and informed yoii that, the weight of the monkey was sufficient to. drive', piles into position at-.the other end, would you have been satisfied that everything 'was ■ going as it.'should be.':—C'rtjir-iy. hot..- I should stop the work at once and investigate the'matter -myself. -.■••■■ ' ■-. In, answer to questions from , Mr. Bolton, witness said he was not'aware of a subsidence of the Gear Company's wharf. .-Had he known of "it; he'-would have had borings taken. He was not.'aware of a subsidence in connection with the,Bona Bay wharf. It was a.wushiugb'ut. '''. ; '■'.■"'■'''

Are you aware that the subsidence of the Bona- Bay- wharf is .attributed .also, .to.'quick-sand?—l-was-informed that it-was due to a change, in the beach, the beach having'been wusheJLaway and the piles being loft hanging. Did you consult Captain' King as to the nature-of the bed.of the harbour on .which the Petone wharf was- erected?—l cannot say that-1 consulted hiin expressly, though.had he known he probably would have told me. : • Did!Captain-King at.any time inform' you that there had been'a subsidence at Petono wharf, or at-any part of it?— No. Cohtinniug, witness said that in view of. what, had taken place/at'the northern end of tho harbpnr, it would be advisable, to take borings if ' works are to-'be 'carried ,'out there.'-. '■ ■:

Mr. Wilford:' Does, not, /the .result.of.yom evidence come to' this—that -.von took no bor-ings;-that you did not consider'borings necessary with' the knowledge 'you : h'ad of a former wharf at the samespot; thatr'yon left the board before the piles were'driven; that the work was then in charge of'the acting-crigirieer.'.with a clerk 'of wdrks,. and the supervision .of; .that •work would be tho duty-of.the acting-engineer? —Tea. '■ ''-. ;■'.'■' '.'.''.'. ,".v'"' ;.,'.'■''''':'.'• "'.