26.31 feet.
The rock vai'ied in height about 2 feet.
In sinking the crib the sand was removed by shovels and hoisting;
the pump being used to keej} the water down.
Subsequent experience on Pier 8 would lead to the belief that this
crib could have been sunk in half the time had no sheet piles been
driven, and the crib built with a cutting edge and battered sides.
Began excavating pit (1885) April 18th.
Stopped by high water " 22d.
Began again June 6th,
" crib " 12th.
" sheet piling (3 inches) " 15th.
Finished " " 17th.
Stopped by high water " 27th.
Began sheet piling (6 inches) July 2d.
Stopped by high water " 5th
Began again (sheet piles) " 21st.
Resumed sinking crib " 23d.
Finished sinking crib August 1st.
Began driving piles " 2d.
Finished driving i3iles " 10th.
Began cutting off piles " 10th.
Grillage finished " 13th.
Began masonry " 1 ith.
Finished masonry " 29th.
Total contents of masonry 378.5 cubic yards.
168 PURDON OX THE VAX BUREN BRIDGE.
Timber in crib 29 764 feet B. M.
grillage 11 233
Iron in crib 960 pounds.
" grillage 1575
Iron in masonry 636 "
Piles. 2 210 lineal feet.
Iron in masonry 636 pounds.
Concrete 136 cubic yards.
Excavation al)OYe water .... 200 ' '
under " 480
Quantities and Weights. i
303.2 cubic yards stone, 155 pounds per foot 1 268 892
197i barrels cement, 290 pounds each ... 57 200
277i barrels sand, 375 pounds each 103 969
11 233 feet B. M. timber, U pounds 50 544
Iron 2 211
Total 1 482 816
= 17 652 pounds, or 8.826 tons per pile.
Superstructure same as in Pier 8.
10 408 pounds, or 5.204 tons per pile.
Total 28 060 pounds, or 14.030 tons per pile.
PiEE 10 OB South Abutment
Is built on a concrete foundation. The level of the ground at the pier
was at an average elevation of 397.
A pit was excavated 15 x 31 at bottom, and 4 feet in height of con-
crete placed on it; the bottom being at an elevation of 376.17, and on
this the masonry was commenced May 21st, 8.35 a.m.
The masonry consists of three footing courses, each 2 feet, with 9-
inch offsets, and on these the masonry begins, 24 feet x 8 feet 1 inch, and
is carried up plumb on back and ends, and with a batter of 2 inches per
foot on face to the under side of the coping; finished 24 feet x 5 feet 9
inches.
The coping is 16 inches thick and 25 feet x 6 feet 3 inches.
The ballast wall is 24 feet x 2 feet 6 inches, and 5 feet 4 inches high.
All the masonry, except coping and ballast wall, which are of Eureka
Springs limestone, is of sand stone from a quarry near Mountainburg,
Arkansas.
Began pit (1885) Mav 9th.
Finished pit "' 16tli.
Began concrete '• 18th.
Finished concrete " 20th.
Began masonry " 21st, 8.35 a. m.*
Finished masonry June 9th.
Total contents of masonry 173.4 cubic yards.
♦First stone of bridge.
PURDON OX THE VAN BUREN BRIDGE. 1G9
68.8 cubic yards concrete, 130 pounds per foot 241 488
112 barrels cement and 124 barrels sand, viz. :
100 barrels mixed 1 to 1, and 12 l)arrels mixed 2 to 1. . .
19.6 cubii- yards limestone, 155 pounds per foot 82 026
136.8 "' sandstone, 139 " •' 513 410
66 barrels cement, 290 pounds each 19 140
114 " sand,. 375 " 42 750
Total 898 814
Area of foundation 465 square feet.
Pressure from substructure:
1 933 pounds per square foot 13.4 pounds per square incli.
Superstriicture :
162-foot truss— total dead and live load, 874 300, half of which goes
to abutment — 940 pounds per square foot, or 6.52 pounds per
square inch.
Total. . . .2 873 pounds per square foot, or 19.92 per square inch.
Cement.
The cement used was all from the Western Cement Association of
Louisville, Ky., and with the exception of two car loads was the "Speed
Mills" brand. Two car loads were obtained jsut uj) in paper sacks con-
taining about one bushel each. As this cement seemed of poor quality,
and did not come up to the sijecifications, not having the maker's name
on it, no more was used.
The specifications were that the cement should be capable of stand-
ing a tensile strain of 40 pounds per square inch when mixed pure,
exposed for thirty minutes in air and twenty-four hours under water.
Of 5 000 barrels tested, only twenty-eight failed to stand this test and
were accordingly rejected.
The average tensile strength of the 5 000 tested was 88. 6 pounds per
square inch.
Tests Avere made by mixing the cement with as little water as possible
while making it a coherent mass. Of this a briquette was moulded and
e cposed thirty minutes in air and twenty-four hours under water, after
which it was broken in a Fairbanks testing machine, which was auto-
matic in its action.
For experiment, some other tests of this cement were made, with the
following results :
Mixed as above and exposed seven days under water, 1 800 barrels
averaged 120.6 pounds.
Also a number of briquettes were kept for a longer period and tested
with the following results :
70 days under water 250 pounds.
100 " " " 445
107 " " " 635 "
122 " " " 437 "
160 " " " 342 "
170
PUEDOX ON THE VAN BUREK BRIDGE.
Two different lots of about twelve briquettes each were mixed 1
cement to 2 sand, and after twenty-four houi's under water showed a
strength of 12.2 and 15 pounds respectively.
A lot mixed 1 cement to 1 sand after twenty-four hours under water
showed a strength of 42 pounds.
A lot mixed 1 cement to 3 sand after twenty-four hours under water
showed a strength of 10 pounds.
Also a lot mixed 1 cement to 2 sand and exposed seven days under
water showed a strength of 20.4 pounds.
On adding up the various amounts used in the work, and adding
what was left over, and what was known to be wasted, only eight barrels
are unaccounted for.
A total of 5 892 barrels was used in the work, which was distribiited
as below :
Working Chambehs.
Cribs.
: Air Shafts.
a,
u ^
1 o
•^•6
M
^-6
-*-3
acs
O*^
Cu*
=«"S
X ..^
~^
H
.a o
-2 a
't'2
>52
^ o
£3
S IB
â– 3.2
S-3
Ah
B'^
MO
wo
5^
n"
ao
O
no
1
68.3
105
1.53
66.3
63
0.92
11.9
12
1.0
2
103
138
1.34
144
195
1.35
14.2
21
1.48
3
91
93
1.02
334.4
297
0.89
2.7
2>
0.9
4
198.4
198
1.0
710
725
1.02
11.6
17
1.46.
5
91
90
0.99
370.5
370i
1.0
7
6J
0.92
6
91
05k
1.05
350.7
331
0.94
8
a
0.62
7
no chamber
89.2
140
1.57
^ !
H >t
93.7
147
1.56
9 1
I< â– <
136
159i
1.16
10 1
68.8
112
1.63
1
Total. . .
612.7
719i
1.12
2,363.6
2,540
1.07
55.4
C4
1.15
Pl.^nt Used.
By William Sooysmith it Son, Contractors for Sul>structure : .
Barge for pressure machinery 22 x 56, 3 feet deep.
*' concrete mixer 20 x 50, 3 "
stone, sand, etc. 1 16 x 50, 3
1 18x50, 3
" " 2 16 x44, 2J
«« <« I 12 X 48 2i "
derrick 1 20x30^2
coal 1 10x30, 2
Pressure machinery consisted of one double and one single Ingersoll
Air Compressor with one 50 and one 60 liorse-jiower bjiler. On same
boat was a double Worthington pump for jet.
1 double engine to run concrete mixer.
1 hoisting engine on derrick barge, and
1 Foster rock crusher and engine.
PURDOX ON THE VAN" BUREN BRIDGE. 171
Bj Masonry Departineut, Union Bridge Companv :
2 barges 26 x 55, 4 feet deep, each with derrick and hoisting
engine, for handling stone.
3 barges 20 x 50, 3 feet deep, for sand and cement.
4 derricks in stone yard worked by 2 hoisting engines.
By Union Bridge Company, for foundations and erecting :
1 barge 22 x 55, 3 feet deep, for pile driver and jet jjump.
1 " 22 X 50, 3 " timber, etc.
2 small coal barges.
A number of skifts.
1 large hoisting engine for land pile driver.
1 hoisting engine (detached), with horizontal boiler on boat for
pile driver and Cameron pump.
2 hoisting engines.
1 9-inch Joliet pump.
1 6-iuch Bush pump.
1 double Came:-on force pump (on inle driver boat).
3 pile drivers (laud), one with 4 700-pound hammer.
2 derricks for unloading and 1 (on trestle) for loading iron.
Final Estimate for Sinking Caissons.
Original Actual Difference
Elevation. Elevation. -f or — .
Pierl 350 351.15 +1.15
2 342 338.47 —3.53
3 332 330.23 —1.77
4 330 329.86 —0.14
5 328 331.24 4-3.24
6 330 330.90 -f 0.90
Difference in favor of Union Bridge Comjianv in
Piers 1, 2, 3, 5 and 6, . 01 foot at -5400 per foot, 6 4 00
Pier 4, 0. 14 feet at ^600 per foot 84 00
^88 00
TKI.\NGtXATION AND LOCATION OF PlERS.
A base line was measured on the south bank of the river, both up
and down stream from axis of bridge, and a series of triangles made to
a point on the north bank. When the distance had been determined as
closely as was possible (in.strument reading to 20 seconds) by doubling
and trebling the angles, the distaice from the base line to Pier 10 was
laid off on each base line, and from those points the several distances of
the piers were carefully measured out both up and down stream, and
points set. At the3e points angles of 45 degrees were turned and refer-
ence points inxt in on north bank of river, so that in locating a pier
three lines were available as a check on each other, viz., the center line
and two lines at an angle of 45 degrees to it.
It was found in locating the j^iers that these lines agreed very closely
(within i inch), excei^t on Pier 2, where there was a difference of 3 J
inches. This was then checked bv a wire from Pier 1, and the line
17:
PURDOX ON THE VAN BUREN" BRIDGE.
which agreed most nearly with the wire used as correct. On the
pier being finished and the false work erected this distance was found
exact.
The caissons were located by first locating the pile-driver boat, and
driving two piles at each corner of the place where the caisson should
be, and 4 feet distant from the caisson. When the caisson was floated
into position it was moored to these piles, and the center line being
marked on it, was brought into exact position, as defined, by three
transits on shore; one on the axis of the bridge and the other two ou
reference points up and down stream. Afterwards, during sinking and
building masonry, only one base line was used until the masonry was
finished, when the center for the span was given by three transits, as at
first.
In measuring the base line a steel wire made for the purpose and
300 feet long was used. First a length of 300 feet was measured very
carefully and repeatedly with a standard 50-foot steel tape, and the 300-
foot wire stretched over this distant- with a spring balance at the end;
the amount of pull required to make the 300 feet being noted and after-
wards used in measuring the base lines.
In pile foundation c mcrete is around heads of piles and in grillage.
Pile foundation, 1 cament, 2 sand, 3 stone Pier 7
,, .< '« " " 8
,< a << '« "9
100 barrels (in sacks), mixed 1 to 1; rest, 2 to 1 " 10
Cement in Masonry.
Pier.
Total Yards.
Barrels
Cement.
Barrels per
Cubic Yard.
379.8
436.2
491
987.4
471
434.2
385.7
386.7
378.5
173.4
222
230.»
264|
678i
244'
0.58
0.54
0.51
250 v.oi
214^ 0.55
201 0.52
00
4,523.9
2,5G8i
0.57
Beds and joints of masonry laid in mortar mxde of 1 cement to 2
Bind; grout mixed 1 to 1.
PURDON ON THE VAN BUREN BRIDGE,
173
SPECIFICATIONS FOR SUPERSTRUCTUKE.
General Description. — The Bridge shall cousist of one draw or pivot
spau of 370 feet from centers of i^iers supporting the adjoining fixed
spans, three fixeel spans of 256 feet each from center to center of piers
and foixr fixed spans of 165 feet each from center to center of piers. The
spans shall be arranged as directed by the Chief Engineer of the St.
Louis and San Francisco Kailway, and shall be designed to permit floor-
ing over the cross-ties to fit it for a highway as well as a railway bridge-
The stringers to supi^ort the track and proposed floor shall be arranged
approximately as below, there being foiir lines of main track stringers
and suitable supports riveted to the floor-beams for two lines of auxil-
iary stringers.
20ft. 1
2* ft
[floor bexm
j 4 ft. |2fi J_ 3 a |2fl.| ^fl. I
2>sfl.
The draw or pivot span shall be constructed on latest and most
approved designs. The turn-table shall be rim-bearing. All cast-iron
surfaces of beams, rim and track shall be planed. The circular girder
will be of wrought-iron, 27 feet in diameter. Wheels shall be at least 18
inches in diameter and 8 inches tread, and turned to uniform size and
made of the best car-wheel iron. The turning gear, elevating screws and
connecting shafting shall be of the best class of finished machine work.
The latches shall be of the usual character, and, as well as the elevating
screws, will be worked from the i^ivot pier. Hand power will be used to
work the machinery and suitable gearing shall be provided.
Open-hearth steel of quality and strength as hereinafter specified
may be used in the top and bottom chords, end posts, main ties and pins
of the three 256-foot spans, and the draw span. The allowable strains
per square inch for steel so used shall be :
1. In compression — 50 per cent, above strain allowed for wrought-iron.
In tension — 40 per cent, above strain allowed for wroiight iron.
In shearing — .30 per cent, above strain allowed for wrought-iron.
2. In calculating strains, the length of span shall be understood to be
the distance between centers of end jjins for trusses, and between cen-
ters of bearing plates for all beams and girders.
3. There shall be a clear head-room of 20 feet above the base of the
rails, and clear width of 18 feet.
i. The wooden floor will consist of transverse floor timbers, extend-
ing the full width of the bridge, supporting the rails and guard beams.
Their scantling will vary with circumstances. They will be furnished
and put on by the Kailroad Company.
5. Spans shall be proportioned to carry the following loads:
First. — The weight of iron or steel in the structure.
Floor.
Dead load.
1T4 PURDOX OX THE TAX BUREX BRIDGE.
Second. — A floor weighing 950 iDouuds perliueal foot of track, to
consist of the rails, ties and guard timbers only.
These two items, taken together, shall constitute the " dead load."
Live loads. The live load shall be as follows:
For chord strains of trusses— 3 000 pounds per lineal foot of
bridge.
For web strains of trusses — 5 000 pounds per lineal foot for a
length of 20 feet and 3 000 pounds per lineal foot on remain-
der of si^an.
For auxiliary stringers— 800 jjounds -per lineal foot.
For main track stringers — (16-foot panel) 6 400 pounds jjer lineal
foot.
For main track stringers — (18-foot i^anel) 6 300 pounds per lineal
foot.
For main track stringers — (20-foot panel) 6 200 pounds per lineal
foot.
For main track stringers— (22-foot i^anel) 6 100 jiouuds per lineal
foot.
For main track stringers — (24-foot panel) 6 000 jDOunds per lineal
foot.
For floor-beams — (16-foot panel) 96 000 pounds, distributed at
AAAA on diagram.
For floor-beams — (18-foot panel) 102 000 pounds, distributed at
AAAA on diagram.
For floor-beams — (20 foot jjanel) 108 000 jwunds, distributed at
AAAA on diagram.
For floor-beams — (22-foot jaanel) 114 OCO jjouuds, distril uted at
AAAA on diagram.
For floor-beams — (24-foot panel) 120 000 pounds, distributed at
AAAA on diagram.
Stresses. The maximum strains due to all positions of the above "live
load," and of the "dead load," shall be taken to proportion
all the parts of the structure.
Lateral 0. To provide for wind strains and vibrations, the toji lateral bracing
in deck bridges, and the Ijottom lateral bracing in through bridges,
shall be proportioned to resist a lateral force of 500 p(Uinds for each foot
of the span; 300 pound.s of this to be treated as a moving load.
The bottom lateral bracing in deck bridges, and the toj) lateral bracing
in through bridges, shall be proportioned to resist a lateral force of 200
pounds for each foot of the span.
Temperature. 7. Variations in temperature, to the extent of 150 degrees, shall be
l^rovided for.
8. All jjarts shall be so designed that the strains coming upon them
can be accurately calculated.
PURDON ON THE VAN BUREN BRIDGE. 175
9. Strain sheets and a general plan, showing the dimensions of the piaus and
parts and general details, must accompany each ijroposal. ^^^^ ^® ^"
10. Upon the acceptance of a projjosal, a full set of working draw-
ings must be submitted for approval bv the Chief Engineer of the Rail-
road Company, before the work is commenced.
11. Unless otherwise specified, the form of truss may be selected by Form ofTruas.
the builder; but to secure uniformity in appearance, it is desired that
all " through " trvisses shall be built with inclined end-posts.
12. In comparing comi^etitive plans, the relative cost of the wooden
floors required will be taken into consideration.
13. The following clauses are all intended to apply to iron construc-
tiou. Parties pro^Dosing to substitute steel for particular parts will be
required to furnish evidence of its strength, elasticity, uniformity in
production and adaptability to the intended pur^jose.
Pkopoktion of Parts.
1. All parts of the structure shall be so proportioned that the maxi- Tensile Strains,
inuui strains produced shall in no case cause a greater tension than the
following:
Pounds per
Square Inch.
On lateral bracing 15 000
" solid rolled beams, used as cross floor-beams and stringers. 10 000
" bottom chords and main diagonals 10 000
" counter rods and long verticals 8 000
" bo. torn flange of riveted cross-girders, net section 8 000
â– " bottom flange of riveted longitudinal plate girders over 20
feet long, net section 8 000
*' bottom flange of riveted longitudinal plate girders under
20 feet long, net section 7 000
" floor-beam hangers, and other similar members liable to
sudden loading ; 6 000
2. Compression members shall be so proportioned that the maximum Compressive
. -11 strains.
load shall in no case cause a greater strain than that determined by the
following formulas:
8 000
P =: X- ^0^' square end comjiression members.
^ "*" 40 000 H-
8 000
P = £,2 for compression members with one i^in and one
^ + 30 000 E' ^1"^''^ ^^^■^•
8 000
P = X- foj^ compression members with pin bearings.
^ ^ 20 000 E^
176
PUKDOX OX THE VAN BUREN BRIDGE.
Shearing
Strains.
Bending
Strains.
Plate
Girders.
P = the allowed compression jjer square inch of cross-section.
L = the length of compression member in inches.
H = the least radius of gyration of the section in inches.
3. The lateral struts shall be proportioned by the above formulas to
resist the resultant diie to an assumed initial strain of 10 000 i^ounds
per square inch upon all the rods attaching to them, produced by ad-
justing the bridge.
4. In beams and girders, compression shall be limited as follows:
Pounds per
Square Inch.
In rolled beams, used as cross floor-beams and stringers 10 000
" riveted plate girders, used as floor beams, gross section 6 000
" " longitudinal plate girders over 20 feet long, gross
section 6 000
" riveted longitudinal plate girders under 20 feet long, gross
section 5 000
5. Members subjected to alternate strains of tension and compression
shall be proportioned to resist each of them. The strains, however,
shall be assumed to be increased by an amount equal to i^ of the least
strain.
6. The rivets and bolts connecting all parts of the girders mtist
be so spaced that the shearing strain per square inch shall not exceed
6 000 i^ounds, nor the pressure ujjon the bearing surface exceed
12 000 pounds jier square inch of the projected semi-intrados (diameter
X thickness of piece) of the rivet or bolt hole.
7. Pins shall be so proportioned that the shearing strain shall not
exceed 7 500 i^ounds per square inch; nor the crushing strain upon the
projected area of the somi-intrados (diameter X thickness of piece) of
any member connected to the pin bs greater than 12 000 pounds per
square inch; nor the bending strain exceed 15 000 pounds per square
inch, when the centers of bearings of the strained members are taken as
the points of ai^plication of the strains.
8. In case any member is svibjected to a bending strain from local
loadings (such as distributing floors on deck bridges), in addition to the
strain produced by its position as a member of the structure, it must be
proportioned to resist the combined strains.
9. Plate girders shall be i3roportioned upon the supposition that the
bending or chord strains are resisted entirely by the upper and lower
flanges; and that the shearing or web strains are resisted entirely by the
web-plate.
10. The compression flanges of beams and girders shall be stayed
against transverse crippling, when their length is more than thirty times
their width.
11. The unsupported width of any plate subjected to compressiou
shall never exceed thirty times its thickness.
PURDON ON THE TAN BUREN BRIDGE. 177
12. Ill members subject to tensile strains, full allowance sliall be
male for rediiction of sestion by rivet-holes, screw-tLreads, etc.
13. The iron in the web-j^l ites shall not have a shearing strain greater
than 4 000 p >nnds per square inch, and no web-plate shall be less than
i inch in thickness.
14. No wrought iron shall be used less than i% inch thick, except in
places where both sides are always accessible for cleaning and painting.
Details of Consteuction.
1. All the connections and details of the several j^arts of the structure
shall be of such strength that upon testing, rupture shall occur in the
body of the members rather than in any of their details or connec-
tions.
2. Preference will be had for such details as will be most acces-
sible for inspection, cleaning and painting.
3. The -web of plate girders must be spliced at all joints by a plate
on each side of the web. T-iron must not be used for splices.
â– 4. When the least thickness of the web is less than -^ of the depth
of a girder, the web shall be stiffened at intervals not over twice the
depth of the girder.
5. The pitch of rivets in all classes of work shall never exceed &
inches, nor sixteen time^ the thinnest outside plate, nor be less than
three diameters of the rivet.
6. The rivets used will generally be f and | inch diameter.
7. The distance between the edge of any piece and the center of a
rivet-hole must never be less than li inches, except for bars less than 2^
inches wide; when practicable it shall be at least two diameters of the
rivet.
8. When plates more than 12 inches wide are used in the flanges of
plate or lattice girders, an extra line of rivets, with a pitch of not over 9
inches, shall be driven along each edge to draw the plates together, and
prevent the entrance of water.
9. In launching jitlate or other iron, the diameter of the die shall in
no case exceed the diameter of the punch by more than -nr of an inch.
10. All rivet-holes must be so accurately punched that when the
several parts forming one member are assembled together, a rivet tV inch
less in diameter than the hole can lie entered, hot, into any hole, without-
reaming or straining the iron by " drifts."
11. The rivets, when driven, must completely fill the holes.
12. The rivet heads must be hemispherical, and of a uniform size for
the same sized rivets throughout the work. They must be full and
neatly made, and be concentric to the rivet-hole.
13. Whenever possible, all rivets must be machine driven.
14. The several pieces forming one built member must fit closely to-
gether, and when riveted shall be free from twists, bends or open joints.
178
PURDON OX THE VAX BUREX BRIDGE.
Lower Chords
Pins.
15. All joints in riveted work, wliether in tension or compression
members, must be fully spliced, as no reliance will be i^laced upon abut-
ting joints. The ends, however, must be dressed straight and true, so
that there shall be no open joints.
16. The heads of eye-bars shall be so j^roportioned that the bar will
*^ ■Bars!'^^'°'^ break in the body instead of in the eye. The form of the head and the
mode of manufacture shall be subject to the approval of the chief engi-
neer of the railroad comjiany.
17. The bars must be free from flaws, and of full thickness in the