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Full text of "The history and construction of Cabin John Bridge, at Cabin John, Maryland."

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file:///X|/Special%20Collections/purgatory/Phi%20Mu/Mothershead,%20Charles/blueprint.txt[5/4/2011 10:00:56 AM] 



THE HISTORY AND CONSTRUCTION Of 
CABIN JOHN BRIDGE, AT CABIN JOHN, MARYLAND. 



A THESIS PREPAEED 
BY 
CHARLES T. MOTHEESEAD 



FOR INITIATION INTO TEE 
BETA CHAPTER OE MAHYLASB 
OF TAU BETA PI FRATERNITY 



JANUARY 15, 1932. 



SUMMHY 

The facts regarding Cabin John Bridge developed in this thesis may- 
be "briefly summarized as follows: 

Situated seven miles west of the City of Washington, D.C., and 
spanning Cabin John Creek, is a bridge which, prior to 1903, was the longest 
masonry span in the world. It was built by the War Department under the 
supervision of General Montgomery C. Meigs, U. S. Corps of Engineers, during 
the years 1857 - 1354, and was used to carry the Washington aqueduct across the 
valley at Cabin John. The bridge derives its name from a hermit called John 
who lived in a cabin on the bank of the creek. 

The course of construction was interrupted for a short time during 
the Civil War and it was feared the arch might be destroyed, but the work was 
completed without mishap. 

The granite arch has a span of 220 feet and a rise of 57.26 feet. 
The abutments are constructed of Port Deposit granite and blue gneiss, and the 
spandrels and parapet walls are built of Seneca sandstone. The conduit 
through the bridge is formed by three brick rings and has an outside diameter 
of 9 feet. 

In repairing the bridge it has been necessary to line the conduit 
with cast iron sectional tubing, place steel tie-rods across both ends, con- 
struct a new roadway, and reset the coping. 



BIBLIOGRAPHY 

1. Records of the Columbia Historical Society, Washington, D.C, 

Volume II - 1899. (An article "by Mr. Wm. T. S. Curtis read before 
the Society on November 1, 1897.) 

2. C a Mn John Bridge, by Alex. J. Yowell. Ihird edition 1898, W a shingtoniana 

Files, Carnegie Library. 

3. Cabin John Bridge, By W. H. Brewton, Washington, D.C. From files at the 

McMillan Reservoir. 

4. House of Representatives - Document Kb. 1329, - Sixty-first Congress, 

3rd Session. 

5. Publication of The Confederate Southern Memorial Association of ITew 

Orleans, La. - 1909 (Library of Congress) . 

6. The original notes of G-eneral Meigs, Chief Engineer of Washington Aqueduct, 

taken from his scrapbook in the Library of the War Department. 



7 Ell A E D 



In presenting this Thesis, the author wishes to ac'mowl edge the 
aid and cooperation rendered "by Mr. Hardy of the Delecarlia Revervoir and Mr* 
McQueen of the McMillan Heservoir, without which, much of the present niaterial 
would be lacking. 



CABIN JOHN BRIDGE 
INTRODUCTION 

Seven miles from West Washington, District of Columbia, better 
known as Georgetown, D.C., upon what is called Conduit Road, which follows the 
line of the Washington Aqueduct from the City limits to the Great Falls of the 
Potomac, is a structure which enjoys and deserves the distinction of being one 
of the most noted bridges of its kind in the world. This bridge, built by the 
United States Government, spans Cabin John Creek. The creek is a stream of 
respectable size which rises at Rockville, Maryland, flows through one of the 
most beautiful sections of the state, and pours its slowly moving waters into 
the Potomac a few hundred feet below the great bridge bearing its name, - a 
bridge of national reknown, which enjoys the distinction of being, prior to 
1902, the largest single arch span of masonry in the world. 

History records but one bridge, or stone arch built before 1902 
which was greater in span than that of Cabin John. This bridge spanned the 
Adda, a tributary of the Po, at Trezzo, in Northern Italy and is supposed to 
have been built in the year A.D. 1380, by order of the Duke of llilan, but in 
the year 1427 was destroyed by the Italian General Carmagnola. It consisted 
of a single stone arch of granite with a span of 251 feet, a rise of 38 feet, 
and at the crown was only 4 feet thick. 

Several large masonry arches have been constructed in Europe, but 
none exceeded or equalled the length of span of Cabin John Bridge. The 
Grosvenor 3 ridge over the River Dee at Chester, England, has a span of 200feet 
and a rise of 42 feet. Within the last few years a single span stone bridge 
very similar in design to that of Cabin John has been built over the River 
Pruth, at Jaranese on the line of the Austrian Stanislaw, Woronieka Railroad in 



- 2 - 



Galicia. It has a single span of 213 feet, seven feet less than that of 
Cabin John. 

At the present time, Cabin John Bridge, although not the longest 
single span of masonry in the world, has not been excelled in the United States* 
Its length of span is exceeded in Europe by the Sidi Kached Bridge, at Constan- 
tine, Algiers, completed in 1915. This bridge has a total length of 1,468 
feet, a main span of 227 feet, and a height of 300 feet. The longest masonry 
arch in the world is the Plaaen Bridge, located at Plauen, Saxony. It was 
completed in 1903 and has a total length of 492 feet, a single arch span of 
?95^ feet, and a height of 58 feet. It was built at a cost of $125,000. 

Cabin John Bridge was primarily constructed for the purpose of 
carrying the Washington Aqueduct across the ravine of Cabin John Creek. Frior 
to the building of the conduit, Washington depended entirely upon wells and 
cisterns for the water supply. As the District of Columbia was under Federal 
jurisdiction, the work of bringing into the city the additional water supply 
from the Potomac at Great Falls was placed in the hands of the Corps of 
Engineers of the War Department. Work was started early in 1857, and the 
bridge was completed in 1864. 

QHiaiN OF THE SAME "CAB III JOHN BRIDGE" 
The origin of the name "Cabin John" as applied to the creek, and 
likewise to the bridge which spans it, is somewhat shadowy and uncertain. 
There is a story to the effect that at an early date, in the 19th century, a 
mysterious character occupied a rough cabin on the banks of the creek a short 
distance above the present site of the bridge. Ee is stated to have led the 
life of a hermit; fishing in the stream, and hunting in the surrounding 



- s - 



forests. The only name he was known by was "John"; sometimes he was spoken 
of as "John of the Cabin"; and also as "Captain John". Upon some of the 
old records of Montgomery County, Maryland, the name of the creek is given as 
"Captain John". The present name "Cabin John" is either a corruption of 
"Captain John" , (of "John of the Cabin". After dwelling in his cabin by the 
creek for a number of years he disappeared in the same mysterious manner in 
which he came, and nothing was ever known of his fate. Proof that there was 
such a mysterious character and that he lived in a cabin on the banks of the 
creek which bears his name, has come from two sources ;- 

1. Captain Fyles, an aged resident, who as well as his father 
before him, had lived in the vicinity of Cabin John Bridge for a good many 
years, stated that when a boy, he had played in and about the Cabin and had 
also gathered arrow and spear heads which were nearby* 

2. In the year 1825, the following lines were found under a de- 
lapidated grainbin in an old mill located on the banks of Cabin John Creek: 

"John of the Cabin" - a curious wight - 
Sprang out of the river one dark stormy night, 
He built a warm hut in a lonely retreat, 
And lived many years upon fishes and meat. 

When the last lone raccoon on the creek he had slain. 

It is said he jumped into the river again. 

As no name to the Creek liy the ancients was given, 

It was called "Cabin John", after John went to Heaven. 



- 4 - 



EABLY HISTORY 

The Initial step in the construction of the Washington Aqueduct 
was taken on April 21, 1853, when Congress, in the appropriation act of that 
date, inserted the following provision! 

- To enable the President to cause the necessary surveys, projects, and 
estimates to be made for determining the "best means of affording the 
cities of Washington and Georgetown an unfailing and abundant supply of 
good and wholesome water, report thereof to be made to Congress at its 
next session, the sum of $5,000 or so much thereof as may be necessary 
(10 Stat. 92). - 

On March 3, 1853, an appropriation of $100,000 was made to be ex- 
pended under the direction of the President of the United States for the pur- 
pose of bringing water into the city (10 Stat. 306). The following addition- 
al appropriations were made in the succeeding years as the work progressed; 
on March 3, 1355 an appropriation of $250,000 (10 Stat. SS4) ; August 18,1856 
an appropriation of $250,000; March 3, 185.7 an appropriation of $1,000,000 
was made for continuing the Washington Aqueduct, and on June 13, 1858, an 
additional sum of $800,000 was granted. 

The first work on the Washington Aqueduct was begun in 1853 during 
the administration of President Buchanan whose Secretary of Wax was Jefferson 
Davis. The engineer of the aqueduct from its inception and including the con- 
struction of Cabin John Bridge was Captain Montgomery C. Meigs, U* S. Corps of 
Engineers. He assumed charge of the work immediately after the appropriation 
of $5,000 was made in 1852, and the surveys, projects, and estimates for the 



- 5 - 



general system of water supply were prepared by him. Many difficulties arose 
in the construction and carrying out of the original plans for the aqueduct - 
valleys had to be spanned and hills had to be tunneled to provide for the 
conduit. 

The most serious obstacle encountered was at Cabin John Hun. The 
ravine was too wide and too deep to fill, and the only remaining solution was 
to construct an aqueduct over the valley. At first it was decided to span it 
with a bridge of masonry, supported on a series of piers and arches, at an 
estimated cost of $72,409. This original plan was changed and it was deter- 
mined that a bridge should be constructed to excel any of its kind on earth 
and at the same time to be a lasting and imperishable monument to the genius 
of its engineer and to the possibilities of modern "bridge building. 

The actual work on Cabin John Bridge was started early in 185?. 
Before the work was started, Captain Meigs selected Mr, Charles T. Curtis to 
act as general superintendent and inspector. Ur. Curtis had had training 
under Col. Thayer in the building of Fort Warren, Boston Harbor and afterwards 
in connection with the Boston Aqueduct. 

The work was rapidly pushed, so that on December 4, 1858, the arch 
was keyed, and by July 1, 1859, the arch stones, as well as a considerable 
portion of the abutments were in position. In July 1860, Captain Meigs was 
detailed to Fort Jefferson, Tortugas, Florida to supervise the public works at 
that place. In the latter part of February 1861, he returned and resumed 
charge of Cabin John Bridge. It is of interest to note why Captain Meigs was 
detailed away from the bridge at such a critical time in its construction and 
also for so short a oeriod. 



- 6 - 



On June 25, 1860, the following provision was embodied in the 
appropriation act of that date: 

For the completion of the Washington Aqueduct, $500,000 to he ex- 
pended according to the plans and estimates of Captain Meigs and under. 
his superintendence. 

Congress by the use of the language in the act intended thus to ex- 
press its approval of the work of Captain Meigs. 

President Buchanan transmitted a message to Congress wherein he 
complained that the clause in the act providing that the money should he ex- 
pended under the superintendence of Captain Meigs, was an interference with 
the prerogatives and rights of the President "to he Commander-in-Chief of the 
Army and Navy of the United States" as it virtually directed that the money 
could not he expended unless Captain Meigs superintended its dishureement. 
The President contended he had the right to send Captain Meigs away from 
Washington to any part of the Union to superintend the erection of fortifica- 
tions or other public works. Thus, it was that Captain Meigs was relieved of 
the charge of the aqueduct and in July 1860, was ordered to Fort Jefferson. 
Puring the six months absence of Captain Meigs at Fort Jefferson, the const ruc- 
tion of the aqueduct was in charge of Captain Henry W. Benhara and Lieut. James 
St.C. Morton, United States Corps of Engineers, and the work was continued by 
them according to the plans of Captain Meigs, which had received the sanction 
of Congress. 

Captain Meigs returned from Fort Jefferson in February 1861, and 
resumed charge of the construction. Shortly afterward Civil War broke out and 
considerable anxiety was felt lest the Confederates should set fire to the wood 



- 7 - 



centering and. so destroy the arch.. But this did not come to pass. However, 
from about May 1861 until July 1863, active work on the "bridge was suspended 
due to the War. 

In May 1861, Captain Meigs became Quartermaster- General with his 
headquarters in Washington. When work was resumed on the bridge in the 
summer of 1863, the control of the Washington Aqueduct was transferred from 
the War Department to the charge of Caleb B. Smith, Secretary of the Interior 
Department, under a joint resolution of Congress. General Meigs, therefore 
ceased to have further charge of the work. Although General Meigs was the 
Chief Engineer, most of the working plans and drawings of Cabin John Bridge 
were prepared by Mr. Alfred L. Hives, the assistant engineer, who was a grad- 
uate of the Ecole des Ponts et Chaussces in Paris. At the outbreak of Civil 
War, Mr. Rives resigned his position and went South to join the Confederacy. 
After the resignation of Mr. Elves in 1861, he was succeeded by Mr. Wm. R. 
Button. Mr. Hut ton is best known in connection with the construction of the 
Washington Bridge over the Harlem Eiver, Hew York. When the Interior Depart- 
ment resumed work on the aqueduct, Mr. Hutton was appointed Chief Engineer. 
He held this position until July 1863, at which time he was succeeded by Mr* 
Silas Seymour. 

Mr. Seymour in his annual report to the Hon. John P. Usher, Secre- 
tary of Interior under date of October 1, 1863, states: 

"The work, so far as executed (with exception of a portion of 
the dam in the Potomac, and the water facings of the district reservoir) 
has been done in accordance with the plans and specifications prepared by 
General Meigs and generally under his own supervision". 



- 8 - 



On December 5, 1863, water was turned into the aqueduct hut it 
was not until the following year that the roadway surface of the bridge was 
completed. 

In 1867, the charge of the aqueduct was again transferred to the 
War Department under Captain D. Dub. Gaillard, and is under the supervision of 
the War Department at the present time. 

INSCRIPTIONS 
One of the interesting sidelights on the history of Cabin John 
Bridge, relates to the erasure and restoration of Jefferson Davis 1 name on 
the tablet of the west abutment. 

Mr. Montgomery ffeigs, son of the late General Meigs wrote the 
Washington Star as follows, September 8, 1892: 

"Permit me, through your collars in the Interest of truth, to 
correct the statement lately published in some newspaper, that the name 
of Jefferson Davis, as Secretary of War, inscribed on Cabin John Bridge 
at the time of its erection was erased by order of my father, General 
Meigs. My father, referring to a similar statement published a year 
or two ago, wrote a member of my family that the erasure was made without 
consultation with him, without his iorowledge, and at a time when he no 
longer had any nontrol whatever over the aqueduct". 

After the death of General Meigs in 1892, Mr. Wm. R. Button, 
former Chief Engineer of the Washington Aqueduct wrote the Star endorsing the 
above newspaper clipping: 

"The above clipping was sent to me from Washington some months 
ago. A recent conversation with Col. Elliott, in charge of the Washing- 
ton Aqueduct induces me to give facts concerning the removal of Jefferson 



- 9 - 



Davis 1 name from Cabin John Bridge, which it seems has "been attributed to 
General Meigs, wholly without reason, he being at the time Quartermaster- 
General. In June 1862, at the request of the Secretary of Interior, the 
Hon. Caleb B. Smith, to whose Department the aqueduct had just been trans- 
ferred, I accompanied the Secretary and a number of Members of Congress on 
a tour of inspection of the aqueduct. Opposite Cabin John Bridge several 
of the party walked to the bridge for a nearer view. Returning in haste, 
the Hon. Galusha Grow complained that General Meigs had put Jefferson 
Davis' name on the bridge. Turning to me the Secretary said, 'The first 
order I give you is to cut Jefferson Davis' name off the bridge.' A 
few days later I was appointed Chief Engineer of the aqueduct. Hot taking 
seriously the Secretary' s remark,.' I did nothing in the matter. A week 
later Mr. Robert Mclntyre, the contractor, arrived to resume work upon the 
bridge, and called to pay his respects to the Secretary of Interior. The 
Secretary told him that Jefferson Davis' name had been put on the bridge 
and he wished he would cut if off, Mr. Mcl n tyre's first work was to re- 
move Mr. Davis' name." 

On February 16, 1909, President Roosevelt ordered the name of Jeff- 
erson Davis restored to Cabin John Bridge ~by the War Department. Four days 
later, February 20, 1909, the S e cretary of War, General Luke E. Wright, repeat- 
ed this order to Ms Chief of Engineers, The entire face of the tablet was re- 
moved and resurfaced without moving it from its position, and the original in- 
scription, including the name of Jefferson Davis, recarved. The work was done 
by J. B. Home, a stone cutter from Moss Point, Miss, for the sum of $127,75. 
He began on Tuesday April 13, 1909, and completed the work on Friday May 14, 



- 10 -. 



1909. The tablet Is five feet high and, eleven feet long. 

Shortly before he was ordered to Port Jefferson, Captain Meigs, be- 
ing apprehensive lest some action might he taken looking to hie removal, and 
desiring to perpetuate his own naroe as Chief Engineer of the bridge, caused the 
following inscription to be cut in deep, imperishable letters upon two of the 
arch stones near the east abutment: 

M. C, Meigs, 
Chief Engineer, 
Washington Aqueduct 
A. D. 1859 
Eecit 

In the Spring of 1861, the following inscription was cut upon the 

tablet in the east ahutment: 

Union Arch 
Chief Engineer - Captain Montgomery 
C. Meigs, U. S. Corps of Engineers, 
Esto Perpetua 

Cabin John Bridge, in the Official B e cords of the War Department, is known as 
Union Arch, by reason of having been constructed "by the Union Corps of Engineers 
and during the Civil War. 

luring the absence of Captain Meigs at Fort Jefferson as previously 
mentioned, Lieut. Morton caused his own name and that of Captain Benham to be 
cut on the face of two of the arch or ring stones near the east abutment imme- 
diately under the name of Captain Meigs,' which had been inscribed there previous- 
ly. Upon his return in February, 1861, Captain Meigs, observing what had beer, 
done, directed that their names should be erased contending that he was Chief 
Engineer, and that it was improper for their names to appear on the bridge as 
Chief Engineers, particularly as they had merely carried out his plans. This 
order was carried out and the erasures are still visible on the arch stones. 



- 11 - 



CONSTRUCTION 

Cabin John Bridge was "bfu.il t mainly of Seneca sandstone, 'blue gneiss, 
^nincy granite and hard well-burned brick laid in cement mortar. In order to 
provide for the transportation by water of the stone and other materials, a 
large dam was built across Cabin John Creek a short di stance above the Chesa- 
peake and Ohio Canal, and a lock was constructed at that point to permit the 
boats to be floated into the pond which at that time filled the valley beneath 
the bridge. The contract for the cut stone for the arch was given to Frederics 
and Field of Quincy, Mass., and called for the delivery to be completed by June 
30, 1858. The granite was shipped to G-eorgetown by vessels, and thence to the 
bridge by way of the Chesapeake and Ohio Canal, 

The first work on the bridge proper began early in 1957. The soil 
was removed until rock foundation was reached, and this rock in turn was blast- 
ed away until the solid ledge of the hill was exposed. All disintegrated por- 
tions of the ledge were removed, the surface smoothed off, and a proper face 
made for the reception of the arch by a bed of cement and broken stone. The 
abutments below the spring line were constructed of dressed Port Deposit granite, 
and the abutment walls were of rock faced ashlar with rubble backing. The cut 
stone arch was backed by a rubble arch of gray Seneca sandstone flagging* in 
slabs not more than ten inches thick, and laid radially to the arch. The con- 
tract for quarrying and cutting the stone in the United States quarry at Seneca, 
Maryland was given to H* L. Sallaher. The spandrels were constructed of rock 
faced ashlar and also had a rubble backing. The abutments and spandrels were 
built hollow with relieving arches and piers in the center. The abutment 






- 12 - 



walls "below the water table were built of blue gneiss. All the remainder of 
the face work, the arched backing, the water table, and the platform were con- 
structed of Seneca sandstone. The backing of walls was done with blue gneiss 
quarried at the site of the bridge* The platform or roof of the bridge was 
constructed of slabs of Seneca gray sandstone, nine inches in thickness and 
two and a half to four feet in width, cut and laid according to the drawings 
with close joints, and secured by dowels and cramps at the ends and sides. 
Grooves were cut on the upper surface to carry off the water from the joints. 
The conduit through the bridge was constructed of brick. 

As the super structure was very massive, it required a corresponding- 
ly heavy wood centering to support it during construction. This structure 
rested upon a series of stone piers, which piers still remain. In addition to 
the rnain centering a further framework was constructed to carry a system of 
travelling cranes by which means the stone was transported to various portions 
of the structure as it was used. The remains of the piers carrying this frame- 
work for the cranes can also be seen in the valley, just outside of the lines 
of the bridge. 

From 1864 to 1872, the only protection for pedestrians and vehicles 
was a low wooden goard-rail constructed of logs and timbers. The present para- 
pet walls of red Seneca sandstone were built between 1372 and 1873. 

The dimensions of the bridge are as follows; 

length - 450 feet over all, including abutments. 
Length of span - 220 feet. 
Else - 57.26 feet. 



- 13 -. 

Radius of intrados - 134.285 feet. 
Radius of extrados - 143.269 feet. 
Thickness at crown - 4.2 feet. 
Width - 20.4 feet. 
Diameter of conduit - 9 feet. 
Surface of roadway above ravine - 100 feet. 
The arch or ring stones are each 2 feet thick, 4 feet deep at the 
crown and 6.2 feet at the spring line. 

There are 11,914.8 cubic yards of masonry, 352.66 cubic yards of 
concrete, and 516 yaards of brickwork used in the construction of the bridge. 
The total cost including the parapet walls was $254,000. 

PRESEBVATION AND REPAIR OF CABIF JOHIT BRIDGE 
In a letter written on January 28, 1911 by C. D. Hilles, acting 
Sgcretary of the Treasury, to be presented before the House of Representatives; 
the matter of the preservation and repair of Cabin John Bridge is introduced 
as follows: 
"Sir:" 

"I have the honor to transmit herewith, for the consideration of 
Congress, copy of a communication of the president of the Board of Commissioners 
of the District of Columbia, of this date, submitting an urgent estimate of 
appropriation recommended by the Chief of Engineers, U.S. Array, and transmitted 
through the Secretary of War, required for the Washington Aqueduct for the 
preservation and repair of Cabin John Bridge, $35,000 of which the sum of 
$20,000 is to be immediately available - 

The necessity for the appropriation can be explained by excerpts 
taken from a letter writtin by W. C. Langfitt, Chief of Engineers, TJ. S. Army, 
Washington, D.C., on January 21, 1911. 



- 14 - 



" - When the water was first admitted to the conduit from Great 
Falls in 1863 a number of leaks were found in the Cabin John 3ridge when there 
was about seven feet of water in the conduit which is nine feet in diameter. 
The water was drawn off, the lower half of the conduit plastered, and after the 
water was again admitted no leakage was observed; the flow being below the 
upper limits of the plastered section. As the consumption of water in the city- 
has increased, requiring the extension and raising of the dam at Great Falls, 
the conduit has been running fuller. As the amount of water passing through 
the conduit increased, the upper portion of the conduit through the Cabin John 
Bridge not having been plastered, it was discovered that the mortar between the 
bricks had worn away to a depth of one inch in some places, and the leakage be- 
gan again. In 1905, the interior was carefully cleaned and all cracks were 
filled with cement mortar. Thus about 90 per cent of the leakage was stopped. 
In 1908 the complete plastering of the upper portion of the conduit was commenced 
and by 1909, 134 feet of the conduit through the bridge had been plastered com- 
pletely with Portland cement mortar. The work was finished late in 1910 and 
stopped the leakage in the center of the bridge, but did not affect the leakage 
between the center and the ahutmBnts" , 

"During inspection, long cracks in the masonry of the conduit were 
noted, on both sides of the center, the axis of the bridge lying almost due east 
and west. These joints were kept carefully filled with mortar and it was felt 
assured that most of the lea ka ge did not come through the joints of the brick 
crown of the conduit. These long cracks lie in the lower quadrant on the 
north side and undoubtedly have been caused by unequal expansion of the two 
sides of the bridge, the south side being exposed throughout the day to the 

direct rays of the sun and the north side always in the shade. This unequal 




- 15 - 



expansion has broken the three brick rings of which the conduit is constructed, 
along the length of the cracks, and the upper quadrant of the ring is moving 
over the lower quadrant at the rate of l/8 inch a year by recent measurments. 
As the masonry of the bridge contracts during cold weather, the cracks in the 
conduit open up, the extent of opening depending upon the degree of cold. It 
has been estimated that the leakage of water through the masonry of the bridge 
in December, 1910 was not less than 2,000,000 gallons per day. The maximum 
capacity of the conduit is 90,000,000 gallons per day." 

"It is proposed to place within the bridge a metal lining either of 
steel or iron tube 8 feet six inches in diameter, surrounded by concrete, or by 
placing of cast iron sectional lining 8 feet in diameter, similar to that used 
in the Washington Aqueduct tunnel under Eock Creek. Either method would be 
satisfactory and render the bridge water- tight, thus preventing the disintegra- 
tion of the masonry in the faqe of the bridge caused by the freezing of water 
in the joints and interstices." 

These recommendations for preservation and repair were endorsed by 
W. H. Bixby, Chief of Engineers, U> S. Array and J» M. Dickinson, S e cretary of 
War. Commissioners of the District of Columbia, Amo H* Rudolph, John A. John- 
ston, and W. V. Judson transmitted to the S e cretary of Treasury, Hon. Frank: l!c- 
Veagh, an estimate of appropriation of $35,000 needed for the Washington Aqueduct, 
for the District of Columbia for the fiscal year ending June 30, 1912, along 
with a letter bearing the President's approval. The result was the letter 
read before Congress written by C. D. Hi lies, acting S e cretary of Treasury. The 
appropriation was approved by Congress on March 2, 1911, The recommended re- 
pairs were completed and consisted of a cast iron lining through the bridge, 



- 16 - 



steel tie rods across "both ends, a new roadway, and a reset coping. The old 
brick roadway over the "bridge was replaced with asphalt blocks by contract for 
$2,012.40. In order to make this surface impervious to water, it was treated 
wi th Tarvia A. 

CONCLUSION 

Years have cone and gone since the completion of the bridge, and 
still it is as solid and immovable as the hills upon which it rests, and, as so 
aptly inscribed on the abutment, - esto perpefrua - it will live forever and r e- 
main for the eyes of generations yet unborn, a momument to the genius and in- 
spiration of its engineer, Montgomery C. Meigs. 




CABIN JOHN BRIDGE 



450' 


G 

1 



Span * BW 



"mwWftffltf f iff ft f /.-// r : 

SECTION A-B 



SCALE, OP FEET 






HOR. SECTION C"D 




Construct ion Commented tB57 
Const r uchon Completed 1304 
Parapet Watts Constructed I87HS73 
Cut Stone Arch-(juwcy Granite 
ffubble Arch- Seneca Sandstone 
Spandnk- Seneca Sana's font 
Parapet Walls- Sen&CQ Sandstone 
Abutments - Gneiss from Montgomery Co, Md. 



SECTION- E-F 



20 
SECTION AT KEY 



SCALE OF FEET 




%9M.IH \ffl.Gb\ 



J 



A 





- 




Tablet on East abutment 




Tablet on West abutment 




Remains of dam built to float boats into pond under 
bridge. 



r 




L 




Part of lock at dam 



r 




1 






L 



J 



Iron door leading to interior of 
afcutment and spandrel