Canadian engineer . the writerthat this geographical description might not be amiss. Before locating Port Mann wharf, two and a half milesof water frontage were carefully sounded, lines of soundingbeing extended from the shore at short intervals, for 150ft. into the river. The location selected gives the best water 394 THE CANADIAN ENGINEER Volume 22. availabe, for although a depth of 30 ft. of water was obtain-ed JOG ft. from shore for practically the whole two and a halfmiles of water fronta^gfe, 45 ft. is found 100 ft. out from theshore for the entire length of the wharf, and for severolhun
Canadian engineer . the writerthat this geographical description might not be amiss. Before locating Port Mann wharf, two and a half milesof water frontage were carefully sounded, lines of soundingbeing extended from the shore at short intervals, for 150ft. into the river. The location selected gives the best water 394 THE CANADIAN ENGINEER Volume 22. availabe, for although a depth of 30 ft. of water was obtain-ed JOG ft. from shore for practically the whole two and a halfmiles of water fronta^gfe, 45 ft. is found 100 ft. out from theshore for the entire length of the wharf, and for severolhundred feet farther west. The accompanying- cross sectionof the wharf gives an accurate idea of the river bed at thepoint in question. The sounding rods were then usedl to determine thenature of the foundation for piling. It was with great diffi-culty that the rods were put down, and with still greaterdifficulty that they vvere withdrawn. The soil is a riversilt for a depth of at least thirty feet. This silt is a very. View of Port Mann Townsite, Looking South.—Takenfrom the Wharf. fine sand, sticky like quicksand, when wet, but much making out a bill of piling, it was thought advisableto drive test piles. Two test piles were accordingly first was given a 25-ft. penetration, going at the lastblow under a six-foot drop of a 4,300-lb. hammer, a distanceof 15 inches. The second pile was given a penetration of35 ft., going at the last blow 6 inches under a lo-ft. piles were allowed to stand over night. Next morningthe shorter pile penetrated only 3 inches under a lo-ft. dropof the hammer, while the longer pile resisted driving- forseven blows under a lo-ft. drop of the hammer, and finally,being started, went 4 inches at a blow. It was accordinglydecided that 30 to 35 feet of penetration was sufficient. Itwas found later that 35 ft. of penetration best suited theinner half of the wharf, while 20 to 25 feet was ample forth2 outer piles. The distance
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