Page 11 - Minutes of Proceedings of Civil Engineers Vol CXCV 1913-14 Part 3 Correspondence

126 coRIrESpoNDENcn oN TIrE coNSTnucrIoN ox' [Minures of rlr. copelantl. of Mr. W. Duff lJruce in the qrso of the Kicltlerpur Docks,r where trouble occurrcd similar to that experiencetl in the White Sbar dock trcnches.z Mr. Copeland therefore suggested thnt if, say, 50-foot lengths of trencb, rvith inter,vals of 50 feet between, had becn excnvtted in the solid, none of these difticulties rvould lr:r,ve beerr nret with ; nnd as thc progr'€ss orr this wall wrl,s at the ra,te of 70 feet per rnorrth, it rvoull have been possible to construct tbe rvholo of tlrr.l qrur,y-rvnll north of the brnk in 12 months. The cxctvittion of the tlock could hnve been cornmenced sirnultlneously with the trenches, and by beginning in the centre and working towrlrtls the walls there need have been no unnecessilry dclny, arrd tbe bllance left irr fr'ont of the rvrr,ll could have been dredgecl orrt when tho rva,ter wa,s let in, assurning, of course, that the exclrvation had been finisheil beforc the rvalls. Fulther, the helvy additionl,l expense entailcd by tho erection of the extra sLrging nnrl shuttering the concrete rvrtll above ground, would have bcen avoided. On p. 50 it was stated that the enclosing bank rvas cut, nnd the water was allowed to enter, before the completion of the walls. This led to the heavy expense occr,sioned by the use of concrete caissons and divers. Mr. Copeland was unable even to irntgine why that rvas done. The sheet piling was regarded as iufdlible, and in this cnse, by returning it against the finished concrete wall, l joint was urade which it was next to impossiblo to makc wrrtertight, unless the timbers were bolted through the wa,ll- lrrtl ovcn so there would be no guftr'a,ntee, since timber would not bolrl with concrete. With regard to the patches and seams of lorrgh a,ntl poor concrete, and to the formation of dry lumps during travcl, suroly tho causes should have been discovered at the mixcrs by tho concrete irrspectors, without putting the contractors to the extrlr oxpr:lrse of rernixing it, on the site. It wns difficult to rea,lize how corrcrete with a proper proportion of rvnter could form hard lnurps aftor t jourrrey of 500 feet in a skip; in fnct, ho w<-ruld hu,vo thouglrt tlurt the vibration would irnprovc it. The underlying prirrciplo of thc Irnproved Construction Cornpany's pr.ocess for rna)rirrg corrcreto pipes was the agikr,tion, on a shaking-tl,ble, of a rlould Iillorl rvith concretc; and the 2-metre pipes trnde by this proceslr for tho IJrrku wrtonvorks were excellent. When the moulds werr.r sl,r'i1rporl, the surflces of the pipe inside lnd out .lvere like a pl:r,storcrl wnll, nrrtl theso pipes rvere not reinforced. With regud to tho rrso of Thanres gravel unscreened, the question of saving I lllinuter of lroceedings Inrt. C.F., vol, ctxi, p, 100, 2 lhid., y1,. f)8 anrl 99.