+=============+===========================+===========================+
| | COST PER FOOT OF HOLE | COST PER DRILL SHIFT |
|Item of Cost.| DRILLED. | |
| +-------+-----+-----+-------+-----+------+------+-------+
| | 15 ft | 9 ft|24 ft|Average|15 ft|19 ft |24 ft |Average|
| | 4 in | 6 in| 6 in| | 4 in| 6 in | 6 in | |
|-------------+-------+-----+-----+-------+-----+------+------+-------+
|Drilling | $0.25 |$0.28|$0.31| $0.28 |$6.95| $7.75| $7.60| $7.45 |
|labor | | | | | | | | |
| | | | | | | | | |
|Sharpening | 0.02 | 0.02| 0.01| 0.016| 0.58| 0.42| 0.34| 0.43 |
| | | | | | | | | |
|Drill steel | 0.007|0.007|0.006| 0.007| 0.19| 0.20| 0.15| 0.19 |
|(5 in. per | | | | | | | | |
|drill shift) | | | | | | | | |
| | | | | | | | | |
|Drill repairs| 0.02 | 0.02| 0.02| 0.02 | 0.61| 0.59| 0.42| 0.54 |
| | | | | | | | | |
|High-pressure|[M]0.05| 0.04| 0.07| 0.07 | 1.39| 1.86| 1.67| 1.82 |
|air | | | | | | | | |
|-------------+-------+-----+-----+-------+-----+------+------+-------+
|Totals | $0.35 |$0.38|$0.41| $0.385|$9.67|$10.82|$10.18|$10.43 |
+=============+=======+=====+=====+=======+=====+======+======+=======+
[M] This is an estimated figure, ascertained by taking a proportion of
the whole charge for plant running.
_General Methods._--Whenever any considerable support was needed for the
ground, segmental timbering was used. In most cases, this was supported
by wall-plates at the springing line, and was set with an allowance for
settlement, so that it would be clear of the work when the masonry
lining was put in. As the twin-tunnel section involved the excavation of
the North and South Tunnels at the same time, the cross-section of the
upper part of the excavation consisted of two quadrants rising from the
springing line and connected at the top by a horizontal piece from 19 to
28 ft. in length. This made a rather flat arch to support by timbering.
The timber for the segmental work was 12 by 12-in. yellow pine. In light
ground the bents were spaced at 5-ft. centers, in heavy ground 2-ft.
6-in. centers.
When the soft ground in the roof was struck, posts had to be used in the
heading to support the caps. When the bench was removed, the posts were
replaced by others down to the bottom of the excavation. These long
posts were a great hindrance to all the work, and each replacement of
short posts by long ones meant a settlement of the caps; consequently,
it was decided to use in the section east of the cut-and-cover, where
all the ground was heavy, a temporary inner bent of segmental timber,
within and reinforcing the permanent bent, and resting on separate
wall-plates. This is shown by Fig. 6. These temporary bents were inside
the work, and were removed as the arch was built. However, the caps
settled considerably in some cases, so that it was not possible to do
away with posting entirely.
In heavy ground the caps were set about 1 ft. above the neat line of the
crown of the brick arch, in some cases they were set only 6 in. above,
but the settlement was often more than this, causing great trouble in
cutting out the encroaching timber when the arch had to be built.
[Illustration: DETAILS OF LONGITUDINAL SECTIONAL SHOWING METHOD OF
PLACING LAGGING IN CROWN WITH SOFT ROOF TYPICAL SECTION LOOKING EAST
FIG. 6.]
In the tunnels east of the cut-and-cover portion, wall-plate headings
were driven (shown by areas marked _A_ on Fig. 5), and, when a length of
wall-plate had been set, the full-width heading was advanced a foot or
two at a time, the timber segmental bents being set up as soon as
possible; lagging was then driven over the cap into the soft ground.
Fig. 6 shows the double set of segmental bents adopted in the 15-ft.
4-in. twin tunnels east of the cut-and-cover section.
When the soft ground came down so low as to interfere with the
excavation of the wall-plate headings, a small heading was driven into
the soft ground on the line of the ends of the caps, and lagging was
driven down from this to the wall-plate heading, as illustrated in Fig.
4.
In the 19-ft. 6-in. tunnels the wall-plate for the inner bent was
supported by a side-bench, termed the "Raker" bench. This was left in
position until the rest of the bench and the middle subgrade conduit
trench had been excavated; it was then possible to support the caps by
two rows of posts from subgrade level, take out the inner bents, and
excavate the raker bench.
The 24-ft. 6-in. twin tunnels, which are at the extreme eastern end of
this section, adjoining the open-cut work of the Terminal Station, and
under Tenth Avenue, were driven from the Terminal Station-West, and the
timbering had to be made very secure on account of the pipes and sewers
in the street above. Detailed records were kept of the amount of timber
used and the cost of labor and material expended in timbering. These
records cover the same portion of tunnel as that for which the detailed
records of drilling costs, previously referred to, were kept. These
records are shown in Tables 9 and 10. It will be noted that the timber
used in blocking, that is, filling up voids outside the main timbering,
amounted to more than two-thirds of the total timber, and that the cost
of labor in erecting the timbering exceeds the prime cost of the timber
by about one-third. The following distinction is made between permanent
and temporary timbering: The permanent timbering is that which is
concreted in when the masonry is built; the temporary consists of the
lower bents and posts, which have to be removed when the masonry is
built.
_Force Employed in Excavation._--A typical day's working force for
drilling, blasting, mucking, and timbering is shown in Table 11.
Where there was any large quantity of soft ground in the roof, the
timber gang was much larger than shown in Table 11, and was helped by
the mucking gang. The drillers did most of the mucking out of the
heading before setting up the drills.
_Excavation of Weehawken Rock Tunnels._--This subject may be dismissed
in a few words, as very few features of interest were called into play.
The rock was of good quality, being the sandstone typical of this part
of the country. Little or no timbering was needed, there were no
buildings above the tunnel to be taken care of, and large charges of
powder could be used.
TABLE 9.--SUPPLEMENTARY ANALYSIS OF TIMBERING, ROCK TUNNEL EXCAVATION
UNDER 32D STREET, EAST OF CUT-AND-COVER SECTION. ANALYZED COST OF
TIMBERING, PER FOOT RUN AND PER BENT.
+=============================+================================
| | _Ke_
| |--------+------------+----------
| |Per foot|Per bent, |Per cubic
| |run of |3 ft, 6 in.,|yard
| |tunnel |center to |excavation
| | |center |
|-----------------------------+--------+------------+----------
|PERMANENT TIMBERING. | | |
|Lumber in feet, B. M. | | |
| Upper Bent. | 274 | 685 | 7.8
| Blocking. | 294 | 735 | 8.3
| Total. | 568 | 1,420 | 16.1
|Cost, in dollars. | | |
| Lumber. | 23.75| 59.38 | 0.67
| Labor. | 37.50| 93.75 | 1.06
| Total. | 61.25| 153.13 | 1.73
| | | |
|TEMPORARY TIMBERING. | | |
|Lumber in feet, B. M. | | |
| Lower Bent. | 479 | 11.97 | 13.6
| Blocking. | 193 | 483 | 5.5
| Total. | 672 | 16.80 | 19.1
|Cost, in dollars. | | |
| Lumber. | 29.13| 72.81 | 0.82
| Erection labor. | 28.85| 72.13 | 0.82
| Removal labor. | 8.29| 20.73 | 0.23
| Total labor. | 37.14| 92.86 | 1.05
| Total. | 66.27| 165.67 | 1.87
| | | |
|GRAND TOTAL. | | |
|Lumber in feet, B. M. |1,240 | 3,100 | 35.2
|Cost, in dollars. | | |
| Lumber. | 52.88| 132.19 | 1.49
| Labor. | 74.64| 186.61 | 3.60
| Total. | 127.52| 318.80 |
|-----------------------------+--------+------------+----------
| | _Ki_
| |--------+------------+----------
| |Per foot|Per bent, |Per cubic
| |run of |3 ft, 6 in.,|yard
| |tunnel |center to |excavation
| | |center |
|-----------------------------+--------+------------+----------
|PERMANENT TIMBERING. | | |
|Lumber in feet, B. M. | | |
| Upper Bent. | 227 | 830 | 5.3
| Blocking. | 164 | 601 | 3.8
| Total. | 391 | 1,431 | 9.1
|Cost, in dollars. | | |
| Lumber. | 16.84| 61.56 | 0.39
| Labor. | 12.82| 46.88 | 0.30
| Total. | 29.66| 108.44 | 0.69
| | | |
|TEMPORARY TIMBERING. | | |
|Lumber in feet, B. M. | | |
| Lower Bent. | 186.33| 681.25 | 4.33
| Blocking. | 42.80 156.50 | 0.99
| Total. | 229.13| 837.75 | 5.32
|Cost, in dollars. | | |
| Lumber. | 9.65| 35.31 | 0.22
| Erection labor. | 10.38| 37.97 | 0.24
| Removal labor. | 9.74| 34.09 | 0.23
| Total labor. | 20.12| 72.06 | 0.47
| Total. | 29.77| 107.37 | 0.69
| | | |
|GRAND TOTAL. | | |
|Lumber in feet, B. M. | 6.20| 22.69 | 14.4
|Cost, in dollars. | | |
| Lumber. | 26.49| 96.87 | 0.61
| Labor. | 32.94| 118.94 | 0.77
| Total. | 59.43| 215.81 | 1.38
|-----------------------------+--------+-----------------------
| | _Ko_
| |--------+------------+----------
| |Per foot|Per bent, |Per cubic
| |run of |3 ft, 6 in.,|yard
| |tunnel |center to |excavation
| | |center |
|-----------------------------+--------+------------+----------
|PERMANENT TIMBERING. | | |
|Lumber in feet, B. M. | | |
| Upper Bent. | 261 | 962 | 4.1
| Blocking. | 408 | 1,508 | 6.5
| Total. | 669 | 24.70 | 10.5
|Cost, in dollars. | | |
| Lumber. | 28.00| 103.38 | 0.44
| Labor. | 29.79| 110.00 | 0.47
| Total. | 57.79| 213.38 | 0.91
| | | |
|TEMPORARY TIMBERING. | | |
|Lumber in feet, B. M. | | |
| Lower Bent. | 350 | 1,291 | 5.5
| Blocking. | 61 | 227 | 1.0
| Total. | 411 | 1,518 | 6.5
|Cost, in dollars. | | |
| Lumber. | 18.45| 68.16 | 0.29
| Erection labor. | 20.83| 76.92 | 0.33
| Removal labor. | 12.16| 44.59 | 0.19
| Total labor. | 32.99| 121.51 | 0.52
| Total. | 51.44| 189.67 | 0.81
| | | |
|GRAND TOTAL. | | |
|Lumber in feet, B. M. |1,080 | 3,988 | 17.1
|Cost, in dollars. | | |
| Lumber. | 46.45| 171.54 | 0.73
| Labor. | 62.78| 231.50 | 0.99
| Total. | 109.23| 403.04 | 1.72
+=============================+========+============+=========
TABLE 10.--TIMBERING:--DETAILED COST OF TIMBER, LABOR, AND
SUPERINTENDENCE. ROCK TUNNEL EXCAVATION UNDER 32D STREET, EAST OF
CUT-AND-COVER SECTION.
+====+=======+======================================+====================+
| | | | EXCAVATION | |
| | | TIMBER USED, IN | IN CUBIC | COST OF |
| | | FEET, B. M. | YARDS | TIMBER |
| | |------------------------+-------------+--------------------+
| | | Main |Blocking| Total | | Paid | | | |
| |Date |timber.|timber. |timber.|Actual| for. | Main |Block.|Total.|
| |-------+-------+--------+-------+------+------+------+------+------+
| |1907 | _a_ | _b_ | _c_ | _d_ | _e_ | _f_ | _g_ | _h_ |
| |-------+-------+--------+-------+------+------+------+------+------+
|_Ke_|May | 18,016| 15,234 | 33,250| 1,736| 1,664| $810| $565|$1,375|
| |June | 14,048| 11,528 | 25,576| 809| 698| 680| 457| 1,087|
| |July | 20,092| 7,339 | 27,431| 1,022| 960| 900| 300| 1,200|
| |August | 6,485| 2,632 | 9,117| 743| 716| 290| 110| 400|
| |Sept. | 1,632| 2,224 | 3,856| 238| 238| 73| 94| 167|
| |Removal| | | | | | | | |
| |-------+-------+--------+-------+------+------+------+------+------+
| |Total | 60,273| 38,957 | 99,230| 4,548| 4,276|$2,703|$1,526|$4,229|
|----+-------+-------+--------+-------+------+------+------+------+------+
|_Ki_|May | | 3,537 | 3,537| 614| 527| | $150| $150|
| |June | 300| | 300| 357| 259| $14| | 14|
| |July | 7,776| 5,811 | 13,587| 530| 404| 350| 233| 583|
| |August | 19,712| 5,702 | 25,414| 925| 890| 887| 220| 1,107|
| |Sept. | 20,556| 9,218 | 29,774| 1,585| 1,501| 925| 325| 1,250|
| |Removal| | | | 1,669| 1,407| | | |
| |-------+-------+--------+-------+------+------+------+------+------+
| |Total | 48,344| 24,268 | 72,612| 5,680| 4,988|$2,176| $928|$3,104|
|----+-------+-------+--------+-------+------+------+------+------+------+
|_Ko_|May | 4,332| 8,788 | 13,120| 250| 188| $175| $366| $561|
| |June | 7,132| 10,017 | 17,149| 496| 347| 324| 396| 720|
| |July | 3,070| 200 | 3,270| 626| 606| 134| 10| 144|
| |August | 10,704| 2,102 | 12,806| 718| 709| 481| 80| 561|
| |Sept. | 2,400| 245 | 2,645| 396| 324| 108| 8| 116|
| |Removal| | | | 209| 211| | | |
|----|-------+-------+--------+-------+------+------+------+------+------+
| |Total | 27,638| 21,352 |48,990 | 2,695| 2,385|$1,242| $860|$2,102|
|----|-------+-------+--------+-------+------+------+------+------+------+
| |Grand |136,255| 84,577 |220,832|12,923|11,649|$6,121|$3,314|$9,435|
| |total | | | | | | | | |
+====+=======+=======+========+=======+======+======+======+======+======+
+====+=======+=======+=======+=======+=======+======+=======+=====+=====|
| | | | | COST PER | COST PER |
| | | | | CUBIC YARD | CUBIC YARD |
| | |COST OF| TOTAL | (ACTUAL). | (PAID FOR). |
| | | Labor | Cost. |-------+-------+------+-------+-----+-----+
| |DATE | | |Timber.|Labor. |Total.|Timber.|Labor|Total|
| |-------+-------+-------+-------+-------+------+-------+-----+-----+
| | | | | _h_ | _i_ | _j_ | _h_ | _i_ | _j_ |
| | | | | --- | --- | --- | --- | --- | --- |
| |1907 | _i_ | _j_ | _d_ | _d_ | _d_ | _e_ | _e_ | _e_ |
|----+-------+-------+-------+-------+-------+------+-------+-----+-----+
|_Ke_|May | $1,792| $3,167| $0.79 | $1.03 | $1.82| $0.82 |$1.07|$1.90|
| |June | 1,576| 2,663| 1.34 | 1.95 | 3.29| 1.55 | 2.25| 3.81|
| |July | 1,580| 2,780| 1.16 | 1.55 | 2.72| 1.25 | 1.64| 2.89|
| |August | 300| 700| 0.53 | 0.40 | 0.94| 0.57 | 0.41| 0.98|
| |Sept. | 60| 227| 0.70 | 0.25 | 0.95| 0.70 | 0.25| 0.95|
| |Removal| 663| 663| | | | | | |
| |-------+-------+-------+-------+-------+------+-------+-----+-----+
| |Total | $5,971|$10,200| $0.91 | $1.51 | $2.22| $1.00 |$1.40|$2.40|
|----+-------+-------+-------+-------+-------+------+-------+-----+-----+
|_Ki_|May | $100| $250| $0.24 | $0.16 | $0.40| $0.28 |$0.19|$0.47|
| |June | 44| 58| 0.04 | 0.12 | 0.16| 0.05 | 0.17| 0.22|
| |July | 525| 7,108| 1.10 | 0.99 | 2.09| 1.44 | 1.30| 2.74|
| |August | 1,018| 2,125| 1.20 | 1.10 | 2.30| 1.24 | 1.14| 2.38|
| |Sept. | 1,028| 2,278| 0.79 | 0.65 | 1.44| 0.83 | 0.68| 1.51|
| |Removal| 1,139| 1,139| | 0.68 | 0.68| | 0.81| 0.81|
| |-------+-------+-------+-------+-------+------+-------+-----+-----+
| |Total | $3,854| $6,958| $0.55 | $0.68 | $1.23| $0.63 |$0.77|$1.40|
|----+-------+-------+-------+-------+-------+------+-------+-----+-----+
|_Ko_|May | $303| $864| $2.24 | $1.21 | $3.45| $3.00 |$1.61|$4.61|
| |June | 562| 1,282| 1.45 | 1.18 | 2.58| 2.07 | 1.61| 3.68|
| |July | 156| 300| 0.23 | 0.25 | 0.48| 0.23 | 0.26| 0.49|
| |August | 727| 1,288| 0.78 | 1.01 | 1.79| 0.80 | 1.02| 1.82|
| |Sept. | 400| 516| 0.29 | 1.01 | 1.30| 0.36 | 1.23| 1.59|
| |Removal| 535| 535| | 2.56 | 2.56| | 2.54| 2.54|
| |-------+-------+-------+-------+-------+------+-------+-----+-----+
| |Total | $2,683| $4,785| $0.78 | $1.00 | $1.78| $0.88 |$1.12|$2.00|
|----+-------+-------+-------+-------+-------+------+-------+-----+-----+
| |Grand |$12,508|$21,943| $0.73 | $0.97 | $1.70| $0.81 |$1.07|$1.88|
| |total | | | | | | | | |
+====+=======+=======+=======+=======+=======+======+=======+=====+=====+
+====+===========+======================+
| | | COST, PER 1,000 |
| | | FT., B. M., OF |
| | | TOTAL TIMBER. |
| | |-------+------+-------|
| | | Total | | |
| | Date |timber.|Labor.|Total. |
| |-----------+-------+------+-------|
| | | _h_ | _i_ | _j_ |
| | | --- | --- | --- |
| | 1907 | _c_ | _c_ | _c_ |
|----+-----------+-------+------+-------|
|_Ke_|May |$41.35 |$53.89| $95.24|
| |June | 42.50 | 61.62| 104.12|
| |July | 43.74 | 57.60| 101.34|
| |August | 43.87 | 32.90| 76.77|
| |Sept. | 43.31 | 15.56| 58.87|
| |Removal | | | |
| |-----------+-------+------+-------|
| |Total |$42.62 |$60.19|$102.81|
|----+-----------+-------+------+-------|
|_Ki_|May |$42.41 |$28.27| $70.68|
| |June | 46.66 |146.33| 193.33|
| |July | 42.91 | 38.64| 81.54|
| |August | 43.56 | 40.06| 83.61|
| |Sept. | 41.98 | 34.53| 76.51|
| |Removal | | | |
| |-----------+-------+------+-------|
| |Total |$42.75 |$53.09| $95.84|
|----+-----------+-------+------+-------|
|_Ko_|May |$42.76 |$23.10| $65.86|
| |June | 41.98 | 32.77| 74.75|
| |July | 44.04 | 47.70| 91.74|
| |August | 43.80 | 56.77| 100.57|
| |Sept. | 43.85 |151.23| 195.08|
| |Removal | | | |
| |-----------+-------+------+-------|
| |Total |$42.91 |$54.75| $97.65|
|----+-----------+-------+------+-------|
| |Grand total|$42.73 |$56.65| $99.38|
+====+===========+=======+======+=======+
Work was begun on September 1st, 1904, immediately on the completion of
the work on the shaft. The North and South Tunnels in this case are
completely independent, as will be seen from Plate XXXIV. The procedure
adopted was to drive a top heading on the center line of each tunnel and
to break down the bench from this. The drilling was at first supplied
with steam power from a temporary plant, as the contractor was at that
time installing his permanent plant, which was finished at the end of
November, 1904. At this time the rate of advance averaged 3½ lin. ft.
of full section per day of 24 hours. By the end of January the Weehawken
rock tunnels were completely excavated, and by the middle of April,
1905, the excavation for the shield chambers was finished; the erection
of the shields was started at the end of that month.