. Engineering and Contracting . used in a joint. The joint was then deflected 5° and testedunder a hydraulic pressure of 100 lb. per square inch beforeit was launched. The pipe-laying scow was 40 by 125 ft. with a TO-ton der-rick. It was held in position by ten anchors. Originallythe cradle was swung from this derrick over the side of thescow, but later it was carried by cables running over a trun-nion at one end. The cradle was built of structural steel, asshown in Fig. 1. It was 168 ft. long, .S ft. wide and 10 , and weighed nearly 60 tons. The pipe was so tight when laid that no sati
. Engineering and Contracting . used in a joint. The joint was then deflected 5° and testedunder a hydraulic pressure of 100 lb. per square inch beforeit was launched. The pipe-laying scow was 40 by 125 ft. with a TO-ton der-rick. It was held in position by ten anchors. Originallythe cradle was swung from this derrick over the side of thescow, but later it was carried by cables running over a trun-nion at one end. The cradle was built of structural steel, asshown in Fig. 1. It was 168 ft. long, .S ft. wide and 10 , and weighed nearly 60 tons. The pipe was so tight when laid that no satisfactory mea-surement of the leakage could be obtained. The only troubleexperienced was in the early stages, when the pipe was testedunder a pressure of 120 lb. to the square inch with one endfree in the cradle. One of the joints just beyond the end ofthe cradle buckled and was straightened and replaced by aharness and recalked with lead wool by divers. In dredging the trench about ,000 pu. yd. of material. Fig. 3—Making Up a Joint,of the joint would be to loosen the lead so that after the pipereached its final position on the bottom it would be necessaryto calk the joint again. To do this in such a depth of waterwould be very difficult. Experiments were accordingly madeto ascertain if it were possible to design a joint which wouldpermit the necessary motion and yet remain tight. It wasnot possible to find any material which did not shrink in cool-ing and tbus make calking necessary. Joints calked withlead wool proved tight but were not flexible. It was flnallydecided to pour the joints in the usual way and then attemptto calk them by forcing in lead pellets under great pressureto compensate for the shrinkage of the lead joint in cooling,estimated at about 10 per cent. Fig. 5—Flexible Joint for Hackensacl< River Pipe. were removed, the maximum depth of trench being about 38ft. In general the material, fine sand and silt, stood on slopesof 2 horizontal to 1 vertical,
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