Engineering and Contracting . Per i-u. yd. $4,133Tolnl ro«t p«r llneiil. foot, $»t perccntnccii: For mnterlnl and plant. B4por cent; for Inhor. 16 per cent. Chicago mixer, holding 25 cu. ft. of dry ma-terial, was used. .Adjustable spouts wereiiseil for pouring the concrete, the spout-manstanding on braces in the trench and deflect-ing the concrete to any point required. Thepouring was made in three runs, each usuallybeing about 16 ft. long. The first or dish ex-tended to 2 ft. above the bottom of the 202 Engineering and Contracting \ol. XLI. No. 6
Engineering and Contracting . Per i-u. yd. $4,133Tolnl ro«t p«r llneiil. foot, $»t perccntnccii: For mnterlnl and plant. B4por cent; for Inhor. 16 per cent. Chicago mixer, holding 25 cu. ft. of dry ma-terial, was used. .Adjustable spouts wereiiseil for pouring the concrete, the spout-manstanding on braces in the trench and deflect-ing the concrete to any point required. Thepouring was made in three runs, each usuallybeing about 16 ft. long. The first or dish ex-tended to 2 ft. above the bottom of the 202 Engineering and Contracting \ol. XLI. No. 6. trencli ; the second, or sides, extended 2 tlic springing line; the third or archcompleting the section. The invert wasshaped up with a wooden template or bulk-head, conforming to the inside and outsidelines of the masonry, on which the forms wereplaced after the concrete was set. The formswere built up of Jxti-in. lagging, laid on , bent to shape. At the springing Crown Plank £10 Plank-Wedges -iM. Fig. 3. Detail of Timbering in Place to Sup-port Roof in Tunnel Section of So. 52ndAve. Sewer. line, a Oxi1-in. timber rested on angles boltedto the channel, being held in place by a % running through both timber and the sides were poured and set, thebraces were removed and the lagging placedfor the crown. The channels for the arcliwere reinforced with two plates. Xo manholes were built and no lateral con-nections were made, but 24-in. tile were setin the arch at intervals for future contract specified a concrete composedof 1 part Portland cement, 3 parts sand, and•5 parts crushed stone or gravel; the engineer,under the specifications, having the right tovary the proportions of fine and coarse ag-gregate, but maintaining the proportion of 1part cement and 8 parts aggregate. Gravelproved very satisfactory. The mix was fairlywet, except on the crown of the arch, wherea dry mix was necessary to prevent the con-crete runni
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Keywords: ., bookcentury1900, bookdecade1900, bookpublisherchicago, bookyear19
