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Hi DESIGN OF A FALSE CONCRETE he
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THESIS FOR DEGREE OF ©. E. 7
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SUPPLEMENTARY
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IN BACK OF BOOK

 
MAY 5 - 1913
DESIGN OF A FALSE CONCRETE ARCH RAILROAD BRIDGE
AT EAST BOULEVARD, CLEVELAND, OHIO

Thesis for degree of C. E.

John Griffith Cavanagh

1913
THESIS
94624
DESIGN OF A FALSE CONCRETE ARCH RAILROAD BRIDGE
AT EAST BOULEVARD, CLEVELAND, OHIO

The conditions which govern the design of structures
used in the elimination of a series of grade crossings in
cities are of various natures. The primary object in the
design of any bridge is to provide a structure that will
safely carry the traffic. The secondary object may depend
upon local conditions, legal or municipal requirerents,
cost or results desired to be attained.

The City of Cleveland, desiring an entrance to a
park, opened a street known as East Boulevard. In order to
cross the tracks of The New York, Chicago and St- Louis
("Nickel Plate”) Railroad, a bridge to carry the railroad
traffic was built spanning the street. The street was de-
pressed to allow the proper vertical clearance and the
slopes graded to harmonize with the surrounding landscape.

In 1909 the City of Cleveland and the Village of
East Cleveland passed ordinances granting The Cleveland
Short Line Railway permission to construct a two track rail-
road across several streets,

A desirable location for the Cleveland Short Line

Railway for about three miles through Cleveland and East
Cleveland was found to be adjacent and parallel to the
tracks of the “Nickel Plate” Railroad.

No grade crossings were allowed in the con-
struction of the Oleveland Short Line Railway, which
made it necessary, in order to use the above mentioned
location, to eliminate the grade crossings of the Nickel
Plate Railroad through the zone where the tracks are
adjacent.

When the grades of the respective railroads
were established the elevation of the Cleveland Short
Line Railway at East Boulevard was about three feet more
than the elevation of the Nickel Plate Railroad at this
point.

The City of Cleveland established the new street
grade, which was only slightly changed from the old
grade, and requested that a concrete arch bridge of an
artistic design be built to carry the railroad traffic
of the two railroads.

The difference in elevation of the railroad
tracks and a horizontal plane at a given distance above
the street surface fixed by the City ordinance for the
under clearance of the bridge was great enough to permit
the construction of a concrete arch under the Cleveland
Short Line tracks but not under the Nickel Plate tracks.

After the design of the Oleveland Short Line

arch was completed a design was made of a steel and con-

2
orete structure having the appearance of a concrete arch.
This structure was placed adjacent to the concrete arch,
to carry the Nickel Plate traffic, and consisted of a
through plate girder bridge, with concrete floor slab and
wing abutments and concrete fascia and soffit arches to
conceal the steel.

The bridge was designed for Cooper's Class E-60
loading and according to The N. Y. Cc. & St. L. Railroad
Company's specifications.

Width of street 54'feet

Angle between bridge and street, 90 degrees

Span center to center of supports, 58.3 feet
Distance center to center of tracks 16 feet

Track alignment 3° 5' curve

Design of Outside Girder.

Dead load to be carried by outside girder.

Estimated weight of steel in girder 37600 lbs.
" " ‘1 t " floor beans 27000 lbs.

" " " concrete and drainage
gutter 130410 lbs.
" fn " ballast 55680 lbs.

250090 lbs.
(Notes Ballast is computed to top of tie and the weight
of the track is neglected.) —
Dead load end shear = 250690 4 2 = 125345
Live load end shear (from tables for Cooper's
Clase E-60 loading for
58.3' span) 143610
(400 ) (when L = loaded
Impact = live load (300+tL ) length of bridge 120230

in feet)
Centrifugal force end shear (Eq. 6 Plate A) 16850
Centrifugal force impact 12140
Total end shear = 418165

The web is taken with a depth of 84 inches
End shear 418165 divided by 13500 (shearing resistance of
one square inch of web) '= 30.9 square inches = net section
of web necessery to resist the end shear.

The number of rivets necessary to resist 418165
lbs. in bearing on 1/2" web plate = 40. Use two rows of
7/8" rivets and assume web with thickness of 1/2". Then
net section of web * 84 x 1/2 - 20 x 1/2 (rivet holes 1"
in diameter) = 32 square inches.

Bead load bending moment = 1/8 w 1° where 1 is
length and w is load in pounds per foot. . . . 1826900

Live load bending moment (from tables for
Cooper's Class

E-60 loading) 1852000
(_300__)
Impact =(300+L ) live load bending moment 1550640
Centrifugal force bending moment (See Eq.7
Plate A ) 208100
Centrifugal force impact 17<E00

SG IEi40 foot lbs
5612140 foot pounds x 12 = 67345680 inch lbs.
6734580 inch lbs. —& 84.2 effective depth of girder

= 799830 lbs. tension in flange caused from load that
tends to produce bending in a vertical plans.

799830 + 18000 (allowable value of 1:sq.in. in tension)
= 44.44 squars inches of flange necessary to resist the
bending moment in a vertical plane.

The centrifugal force tends to cause a bending moment in
a horizontal plane which equals the bending moment in the
vertical plane x (Plate A)

s = 192 inches
h = 107 inches

Live load bending moment equals

2081000 x 192 = 370400

Impact = 210120 ,
80620 foot lbs. x 12 = 8165240 inch lbs.

8166240 — 192 = 42532 1bs. tension in lower flange
42532 — 18000 = 2.36 sq. inches of flange area necessary
to resist bending in horizontal plane due to the centri-
fugal force.
44.4442.36 = 46.8 sq. inches of flange area necessary to
resist the bending moment.
2 angles 6"x6"x7/8" = 19.48 sq.in. - 3.50 sq.in

for rivet holes = 15.98

1 plate 3/4"x16" = 12.00 sq.in. - 1.50 sq. in.
for rivet holes

10.50 full
Leng t.
1 plate 3/4"x16"

12.00 sq.in. - 1.50 sq.in.

for rivet holes 10.60x40'6"

10.50x29'0"
a7. net

arnea

1 plate 3/4"x16" = 12.00 sq.in. - 1.650 sq.in.

for rivet holes
Design of Inside Girder.
Dead load to be carried by inside girder.

Estimated weight of steel in girder 60700 lbs.
Estimated weight of steel in floor beams 54000 lbs.
Estimated weight of concrete floor 240440 lbs.
Estimated weight of ballast 111360 lbs.

, 400 lbs.

(Notes Ballast is computed to top of tie and the weight
of the track is neglected.)

Dead load end shear = 466400 + 2 = 233200 lbs.
Live load end shear (from tables for Cooper's

Class E-60 loading) 287220 lbs.

Live load impact =. end shear |=70o— = 206800 lbs.

: 2 727220 lbs.

(Note: Maximum impact occurs when both tracks are loaded
and L = 8 x 68.3 = 116.6)

‘There is no end shear caused by centrifugal force as the
maximum end shear occurs when both tracks are loaded and
vertical reactions due to centrifugal force are balanced.
End shear 727220 — 13500 (shearing value of 1 sq- inch of
web) = 53.37 squere inches of web required to resist the
end shear.

With web 13/16" in thickness and 84" wide the gross area
is 68.25 square inches. The strength of one 7/8" rivet
to resist 13500 lbs. per square inch in double shear is
16240 lbs.

727220 + 160240 = 45
Number of rivets necessary to carry 3/% of the end shear
from the web to the end stiffeners as allowed by spec-
ifications is 34.

If two rows of rivets are used the area to be
deducted from the gross section of the web is 17 x 13/16
(rivet holes 1" in diameter) = 13.75
68.25 - 13.75 = 54.50 square inches net section of web.
Dead load bending moment = 1/8 w 1” = 4598890
Live load bending moment (from tables)= 3704000

00_)
Impact RE) live load bending moment = 2666880
9769770 foot lbs.

9769770 x 12 = 117237240 inch lbs.
117237240 + 84.93 (effective depth of girder) = 1380398 lbs.
tension in flange caused from load that tends to produce
bending in a vertical plane.

1380398 + 18000 (allowable value of 1 sq. in. in tension)

= 76.7 square inches.of flange necessary to resist the
bending moment in «. vertical plane.

The centrifugal force tends to cause a bending moment in a

horizontal plane Mp, = os a 8 Plate A = 740800

Impact = (300 )L LBM = 533370
(300 L) 1274170 foot lbs.

1274170 x 12 = 15290040 inch pounds.
15290040 + 192 = 79635 lbs. tension in lower flange.
79635 —~ 18000 = 4.42 sq. inches of flange area necessary to

resist the bending moment in a horizontal plane.
76.7 + 4.42 = 81.12 square inches of flange necessary.

2 angles 8"x8"x1-1/8"= 33.46 sq.in. area - 6.75
| for rivet holes = 26.71
16.25 sqein. area - 1.62

1 plate 13/16"x20"

for rivet holes = 14.63 full
length
1 plate 3/4" x 20" = 15.00 sq.in. area - 1.50
for rivet holes = 13.50x44'0"

1 plate 3/4" x 20" = 15.00 sq.in. area - 1.60
for rivet holes = 13.50x35'6"
15.00 sq.in. area - 1.50
for rivet holes = 13.50x25'6"
Sl. 94 net
area

1 plate 3/4" x 20"

Length of cover plates determined by formula

1’ =] joe's"
A

where 1 is total length of span, a, a', a", are areas of
cover plates from outside towards flange angles, and A is

total area of flange.

Design of Floor Beams.
The floor beams are spaced 16" apart.
The dead J.oad supported by the floor beams per lineal foot
of bridge is approximately 8000 lbs.

The dead load end shear on one floor beam

= g000 , 16 = 5337
2 ~*~ 12 299

The live load end shear is
computed from the special
loading of 72000 lbs. dis-
tridutei uniformly over an
area of five feet longi-
tudinally and ten feet
transversely (from sp3ci-
fications)

Live load end shear = 72000 x l
2

”
ts |:
6 fo

onl

9690

sits:

Inpact
Leac load bending moment = 1/8 wi” =

e152
Live load bending moment = 9600 x 8 - 9600x2-1/2= 52800

Impact 52800
126933 foot lh:

126933 x 12 = 1523200 inch lbs.
1523200 + 18000 (allowable stress in tension) = 84.62
required.

A 15 inch 65 lb. I beam has a section modulus of &4.8

Concrete Fascia Arch.

A concrete fascia arch reinforced with a
steel truss is placed in front of the outside girder.

The fascia arch has contours, copings and panels exactly
like the face of the concrete arch between street lines.

The face of the wings of the abutments and
the fascia arch form a continuous surface that has the
appearance of a concrete structure exactly like the face
of the concrete arch.

The steel fascia truss is designed as a simple
arch truss to carry the weight of the steel and concrete
in the arch. The panel loads are computed from the amount
of material in the arch considering the weight of concrete
as 150 lbs. per cubic foot and the weight of steel as
490 lbs. per cubic foot. The stresses and size of shapes

are as shown on the strain sheet,
Design of Grillages.

The bearing value of concrete (from specifications)
is 500 lbs. per square inch,

The end shear of the outside girder is 418166
pounds.
418165 + 500 = 836.33 square inches bearing area of
concrete necessary to support load at one end of outside
girder.

A 16 inch 42 lb. I beam hea « flange 5-1/2 inches
wide.

Four I beams have an area of 4 x 5-1/2 = 22
square inches per lineal inch of bean.
836 — 22 = 38 inches = length of four 15" - 42 1b. I beams
necessary to distribute the load carried by one end of the
outside girder to the conorete abutment.

The end shear of the inside girder is 727220 lbs.
727220 — 500 = 1454 sq. inches bearing area of concrete
necessary to support load at one end of inside girder.
1454 — 22 = 66.1"
5' -~ 7" = length of four 15" - 42 lbs. I beams necessary
to distribute the load carried by one end of the middle

girder to the concrete abutment.

1O
Method of Grouping Rivets for Floor Beam Connections,

sd

Minimum rivet pitch for flanges p= 7

Where s = least value of rivet to resist shear or bearing,

 

dad = distance between center of rivet lines,
V = vertical reaction at support.
For inside girder.
16240 x 75
~~ —_— 007
727220 1.67 inches

Two rows of rivets with 3 inch spacing are sufficient to
transmit the stress from the flange to the web.

For a space of 16 inches, which is the distance
from center to center of floor beams, the number of rivets
necessary to transmit the stress from the flange to the
web is 16 + 1.67 = 10 rivets.

Near the ends of the girdszr where the greatest
number of flange rivets are required the rivets are grouped
in three rows so spaced to allow three rivets in each row
between the floor beam connection angles. The object of
this arrangement is to provide sufficient number of rivets
between floor beam connections to transmit tho flange
stress to the web so it will not be necessary for the
rivets in the floor beam connections to act as flange

rivets.

ll
Method of Determining Centrifugal Force Stresses.

 

 

 

 

 

 

From the specifications the centrifugal force
due to the curvature of the track shall be considered for
curves from «# degrees to 10 degrees as 10 percent of the
live load and acting at a point 6 feet above the top of rail.

W = total load on one girder with one track loaded
F = 2x10% of W= W Eq. (1) With two tracks loaded.

 

Fh = PS 5 Eq. (2)
P = Fh
S Eq. (3)

P = Summation of p, py Ps eos Eq. (4) p = floor beam reactio
ae:
—=:65 5§

Rw Eq. (5)

R =x w hh

P 6 8 Eq. (6)

Likewise My, =

P = uw h

Effective depth of girder ~ tiange stress.
Mp =

F ee on lower flange only, Eq. (8)

Flange stress is “E = uy Eq. (9)

h= approximately 9 ft. for E. Boulevard

a Plate A
The floor beams are attached to the girders
with the lower flanges of the floor beams placed at
the same elevation as the lower flanges of the girdors.
The object of this arrangement which makes it necessary
to ddp the floor beams is to secure sufficient space for
the floor slab and ballast with the limited difference
in elevation of the track and the under clearance of the
bridge.

The height of the abutments is fixed at such
an elevation that the lower flanges of the girders and
floor beams are slightly above the intrados of the
concrete arch at the crown.

Below the floor system of the steel bridge and
making a continuous surface with the intrados of the
concrete arch is supported a plastered surface. The
plaster has a thickness of & inches and is attached to
Style SA wire mosh. At the middle of the bridge the
wire mesh is attached directly to the floor beams. From
the fifth to the eighth floor beam from the center of the
bridge channels varying from about 3" to 8" in width are
attached below the beams. The wire mesh is attached to
the lower edge of the channels. Between the eighth floor

beam and the face of the ebutmonts the channels to which

the wire mesh is attached are supported by 8" - 18 lb.

I beams. The I beams are curved to the exact shape of

1
the intrados of the concrete arch. The lower ends of
the I beams are supported in recesses in the abutments
at the elevation of the springing line of the concrete
arch.

The floor beams are imbedded in concrete
reinforced with Style 5A wire mesh which forms a
slab with its lower surface 2" below the bottom flanges
of the floor beams and its upper surface 6" above ths
top flanges of the floor beams at the center of the
track. ‘The top of the concrete floor slab slopes
downward from the center of the track towards the
girders to carry the water to a 4" tile drain which is
located parallel to the girders and as near the girders
as the gusset plates will permit. From the tile towards
the girders the concrete slab slopes upward to the upper
flanges of the girders. This prevents water coming in
contact with any of the steel work of the bridge except-
ing the upper flanges of the girders. The tile drain is
carried over the backwall of the tridge and through the
abutment to a sewer. A slot 2" x 2" in the top of the
backwall extending the full length of the backwall is
filled with waterproofing. The upper surface of the
floor slab is made of a rich mixture and is well rein-
forced which is the only provision considered necessary

to take care of the drainage between the tracks.

14%
Between the outside girder and the fascia
girder a gutter made of concrete plastered to wire
cloth and supported by rods and brackets fastened
to the stiffeners of the outside girder is provided
to take care of the drainage.

The concrete abutments which act as a support
for the superstructure as well as a retaining wall to
support the fill were designed so that the thickness at
any point is equal to or greater than one half of the
vertical distance between that point and the bridge
seat.

The length of the wings of the abutments are
the same as those of the concrete arch whose length is
one erd one half the vertical distance between the
ground surface and the subgrade of the railroad fill.
This is to provide for a one and one half slope from the
railroad subgrade to the street surface.

The wings of the abutments and the concrete
fascia girder are provided with copings, bays and panels
exactly the same as those of the concrete arch.

The body concrete of the abutments is a
13336 mixture. The exposed’ colored surfaces are a
1:2:4 mixture.

In deciding upon the general color scheme

and texture of the exposed surfaces, the original plan

16
was that the surfaces should be dull pink in color and
that it should show in the texture of the aggregate
three grades, rough or pebbled in the panels, bush-
hammered from the springing line of the arch to the
sidewalk, and polished or ground for the other sur-
faces. This plan was later modified by bushhammering
all surfaces except the panels and rubbing to a finish
all bushhammered areas except copings, belt course,
abutment below the springing line of the arch and

the raised semicircles over the bays in the wings.

A few small samples of the proposed surfaces
were cast in order to determine the amount of coloring
matter necessary and the proper selection and grading
of the aggregate to obtain the desired result. The
proper color was obtained when eighteen pounds of
ferric oxide, sold under the name “Princess Metallic
Dry", was added to two bags of cement. At all times
during the construction of the bridge this proportion
was rigidly adhered to. The ferric ozide was thoroughly
mixed dry with the cement in a box rotating on a rod
through its diagonally opposite corners, giving the
effect of a cube mixer.

Aggregate in the facing was made by crushing
red granite rubble to pass a one inch ring. Screenings
from the crusher were passed over a number 4 and number

8 screen.

16
Aggregates were mixed as follows:-

For bushed and rubbed surfaces except in coping, belt
course, raised semicircles over bays in the wings and
fascia girder:-

53 barrows river sand

2 oarrows # 3 stone (1" ring)

l barrow washed gravel.

2 bags colored cement

making a 1:2:4 mixture.

In copings, belt course and raised semicircles over the
bays in the wings and fascia girder:-

1 part colored cement

43 parts river sand

5} parts washed gravel
For pebbled surfaces in the panelsi-

l part colored cement

1 part granite sand passing a # 8 screen, run as
grout into 4" of granite crushed to pass a 1" screen.
The granite was held against: the forms by # 20 chicken
wire, 1° mesh.
For polished or ground surface as originally planned:-

1 part colored cement

2 parts granite screenings retained on a # 8 screen

Bushhammered surfaces on the abutments between

the springing line and the sidewalk contain the last

17
 

 

 
 

mentioned proportions.

The expensive colored aggregates were used
only in the facing mixture, a veneer about two inches
thick except in panels as noted above.

After the concrete had become thoroughly hard,
the embedding mortar was tooled from between the
particles of granite in the panels. All other areas
were full bushed except the false arch under the
girders, Hammer head points on the panels and 26 point
bush hammers on the full bushed surfaces were the tools
used. Power was furnished by an air compressor mounted
and housed on a flat car.

The results sought and obtained from the design
and construction of the false arch aret- a structure
that safely carries the railroad traffic, is not noisy,
is as near in accordance with municipal requirements
as possible, and has a pleasing appearance that does not

mar the beauty of the surrounding landscape.

18
 

 

 

Before Finishing

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After Finishing

 

 
Beet. 29,1911
Last Boulevard RE ALR

 

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