. Electrical world. ork Telephone Company constructed a largeamount of subway in its suburban territory adjacent to New YorkCity. More than one hundred sets of the concrete tops, about thesame as illustrated in Figs, i and 3, were used on the ordinary brick FIG. 2.—GENERAL VIEW OF BLOCK MANHOLE. ably semi-circular in cross-section, as shown in Fig. 5. When thewalls of the manhole are constructed, these grooves, coming together,form continuous open spaces, extending fmm top to bottom of ihcmanhole, which are filled with liquid cementing material, formingmortar dowels between each block horizont
. Electrical world. ork Telephone Company constructed a largeamount of subway in its suburban territory adjacent to New YorkCity. More than one hundred sets of the concrete tops, about thesame as illustrated in Figs, i and 3, were used on the ordinary brick FIG. 2.—GENERAL VIEW OF BLOCK MANHOLE. ably semi-circular in cross-section, as shown in Fig. 5. When thewalls of the manhole are constructed, these grooves, coming together,form continuous open spaces, extending fmm top to bottom of ihcmanhole, which are filled with liquid cementing material, formingmortar dowels between each block horizontally and vertically, asshown by Fig. I. These dowels not only tend to lock the blocks inposition, but w-ill prevent water from passing through the joints. The roof of the manhole is formed by sliding into position sixflat concrete slabs, each about 5 inches thick, reinforced with ex-panded metal, or steel rods, and with beveled edges. The slabs bearon the flanges of the ^teel beams and on the walls. On FIG. 3.—PLAN OF MANHOLE. manholes with satisfactory results, and a number of the concreteblock manholes were constructed, the blocks being without groovesand rectangular in cross section. Fig. 2 illustrates one of the standard block manholes actually builtin Rye, N. Y., where a railway bridge crossing was made with creo-soted wooden conduit. All of the blocks were made in a large barnin Rye and shipped by wagon or rail to the different places wherethey were to be used. Over 1,200 blocks were made in the barnand only nine were broken in handling. Portland cement concrete was used mixed in the proportion of1-2-4, using three-quarter-inch machine-crushed trap-rock from theConnecticut quarries. The blocks were made in separate woodenmolds and about five hours after mixing were placed in the open airto set from three to five days, before shipping. The average cost
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectelectri, bookyear1883
