CONCRETE POLES TESTED.

Dominion, Volume 3, Issue 912, 3 September 1910, Page 6

CONCRETE POLES TESTED.

EOli, TELEGIIAPH AND .ELECTRiC- ■\ ■■■ ■ '■' • ■ ■ >: iA; -novel. sight was 'at the store-yards ■ of. the Post ■ arid Telegraph ■Departmeht'■'.,in Waterloo Quay.' yester- . day, when a test was-made of a patent, hollow reinforced concrete pole, designed: .to'take the place of wooden .poles, for telegraph, 7 telephone,- arid electric-light purposes,, theinventioii of, Mr., G. J.. Burtinshaw;• ,a ■ ..Wellington-:. clerk:ofworks.. ■ The .test .applied was • a hori r zorital. "pull" strain oh~the top of. the pole, obtained, by pair of ; She6r-legs,-" from.' which was suspended a-block, through which! passed, ropes to the \top of the pole on. the , one hand and a..dropped cradle oil' .the other. By loading' the cradle ; with hundredweight coils ■ of: wire, a; lateral .pull was exerted. -The- concrete/pole .stood 30ft.

•abbTei.'t}ie!'{'groiindj'';aid; i VaVi , .l)un€dh6'ft:; It , .- measures; 11. l-3ihi:'. in 'diameter ,-;'■ is 'octagonal,.■hil shape,.-and £has;. 'a'-'fsiut hollow.. : Tiie,poj6^tapers l 'slightly' to. , ,a' ,solid top.;.'.The"'>pple is'.reinforced- with' ■eight ,'sin;, steel. rbds,.|he]d,.together. 'by wiroil latticing.' .Duriri'g the ■■■test.'..as,■.to', resiliency, : the deflection; was measured ;with'a'plumb-lme.drbppcd from tho top :of'.-the. pole: ■[ _piled, in; the;.cradle,' : :it:Jwas ;most:remarKable to see'.'-. this: apparently ' '.unbendable stick: of-, concrete• slowly, ,bend,.towards the.-weight;' With a ; tpn;' : weight in the , cradle tho' deflection was ■. over 2ft., and ■ .with.;23j■.cwt.i-';the deflection was' 32} in.. ; tliat stage 'a-pieca.of.'cone'reto -fell pff-'abbut ~6ft.r above the ground' on'the concave;-,'side. of-the;. -pole/ arid .tiny; cracks' appeared., at'"the. .'same : height. oil "the concave side.' When the strain, was; taken' off the polo if straightened, up - a' : little, :but did 'not*'"^regain'..•■.'the. perpendicular. ,Mr.' ;'■JohnVHutcliespn ■explained -thati-.tho, concrete, was 7 -still: .rather.i''green;'.''the pole" having' boen.' made ■ only six -'.weeks.'ago, j whilst-.. cpricr,et;e .'needed,three ■month's.'>to.: settle thoroughly.! 1 .Then;: again "they- .had. riot been" able .to get"36ff. ; ;stefel, rods; .and; the ; .srj'ot.wliereth'e : pole''had:.bent was'; the;joint in, therods'. ;'Wliat;was demonstrated;'was'that, reinforced'* concrete. poles'';will,take a. fairly ; ;hqavy . stram, without cracking or bending, arid 1 in .-actual.-use, as wire-carriers.tlio-;pull;6ri f ■one side;:would -be,■'■ s'etVoff against that on the'other, and :. this neutralising; effect would be,"in' favour." : b'f. the now ; po% which; is, it; is said,', practically i imperishable.•'"'. !'■•• .■.'•'.• ;':-,".'. ; '■)' After the test- of the : patent polp,-; a' 36ft;, iroribark; pole':' (lOJin. ;by;|ljin. .at, ;the;grouna, level) was submitted '■.'to."a : similar-test', and' showed' a' Jdeflqction •bf ,; 32in'.;'- ; 'with' i 'Bo'cwt. -.in'v the. cradle. Then as; the. ground . torn's:- between ..the two- poles .shifted.. put-:of ;■. position, -a: further' test was' abandoned,' , ,'.': but.' : . the stout, wooden,pole looked; good enough to .stand another half-toii'st;rain ; . • . \