CHESAPEAKE & OHIO CANAL THE BRIDGES By Edwin C. Bearss DIVISION OF HISTORY Office of Archeology and Historic Preservation January 31, 196l Department of the Interior National Park Service Preface to the 2012 Electronic Edition This edition was transcribed from the original in 2012 with some minor editorial revi- sions and the addition of new information where necessary to bring it up to date. In addi- tion several photographs were replaced with better images and one additional photograph was added. The file is formatted for printing two-sided with a gutter on the binding side. Initial pages of sections have page numbers centered at the bottom but in the upper outside corner on subsequent pages. Karen M. Gray, Ph.D., Volunteer C&O Canal NHP Headquarters Library May 24, 2012 ii CONTENTS INTRODUCTION 1 I. The Georgetown Bridges 1829–1850 4 II. The Georgetown Bridges 1850–1889 17 III. Bridges on the “Washington Branch” 26 IV. Embankment Bridges 31 V. Bridges from College Run to the Seneca Aqueduct 41 VI. Bridges from the Seneca Aqueduct to Antietam Aqueduct 45 VII. Bridges from Antietam Aqueduct to Dam No. 6 54 VIII. Bridges from Dam No. 6 to Cumberland 60 APPENDIXES 77 A. Elwood Morris instructions for an embankment bridge. 78 B. Specifications for the bridge on Section 318 81 C. Nolands Ferry Bridge 84 D. Plans and Specifications for Embankment Bridge on Section 318 86 E. Towpath Bridge at Edwards Ferry Outlet Lock 92 PHOTOGRAPHS AND DIAGRAMS 93 iii PHOTOGRAPHS and DIAGRAMS 1. K Street Bridge across Rock Creek 94 2. Bridge across the basin above Lock No. 1 94 3. Bridge upstream from Lock No. 4. 95 4. Pedestrian Bridge East of the Georgetown Market at Potomac Street 95 5. Towpath Bridge at 34th St. 96 6. Stone Bridge in Georgetown at Wisconsin Avenue (High Street). 96 7. Towpath bridge across canal above the Alexandria Aqueduct, circa 1862–1865. 97 8. The Chain Bridge at Little Falls, circa 1861–1865. 97 9. Photograph of pivot foot bridge at Lock No. 9, circa 1935. 98 10. Plan of pivot foot bridge at Lock No. 9. 98 11. Photograph of pivot bridge at Lock No. 25, circa 1935. 99 12. Photograph from pivot bridge at Lock No. 25. 99 13. Plan of pivot bridge at Lock No. 25. 100 14. Iron Bridge abutment at Whites Ferry, built in 1876. 101 15. Iron bridge at Whites Ferry, built in 1876. 101 16. Iron bridge at Whites Ferry, built in 1876. Photograph September 1959. 102 17. Pivot bridge (on right) at Lock No. 29, Brunswick. 102 18. Road bridge across Lock No. 33 across from Harpers Ferry, circa 1890. 103 19. Towpath bridge crossing the inlet from Dam No. 3 just below Lock No. 35. 103 20. Towpath bridge across the upper end of the Inlet/Guard Lock at Dam No. 5. 104 21. Towpath bridge across the upper end of the Inlet/Guard Lock at Dam No. 5. 104 22. Pedestrian and pivot bridges over the stop gate at the lower end of Big Pool, circa 1900. 105 23. Mule crossover bridge at Lock No. 46 above Little Slackwater. 105 24. Steel and wood bridge at Lock No. 68. 106 25. Covered lattice bridge at Wileys Ford, circa 1890. 106 . iv INTRODUCTION Officials of the Chesapeake & Ohio Canal Company in 1828, the year construction start- ed, were determined to drastically limit the number of bridges crossing the waterway. President Charles F. Mercer on November 12, 1828, outlined this policy in a letter to Resident Engineer W. M. C. Fairfax. In marking the line of the canal, the surveyors were to keep in mind that the Board of Directors, at a recent meeting, had determined that it would be detrimental to future operations if there were numerous bridges across the ca- nal. It was hoped that there would be no need for bridges above Georgetown. Where roads now crossed the line of the canal, it was planned to utilize flat-bottomed ferryboats. Such a scheme would leave the entire canal, except the Georgetown Level, unobstructed by bridges. Opposite the ferry sites, the surveyors were to leave sufficient ground for the excavation of basins capable of receiving and floating scows designed to hold a six-horse team and wagon. Where the elevation of the canal was sufficient, the ferries would be replaced by road culverts. 1 It was soon apparent that because of local opposition the canal company would have to revise its thinking. Chief Engineer Benjamin Wright felt that a pivot or swivel bridge might be the answer. On February 12, 1829, he forwarded to President Mercer a sketch he had prepared of a pivot bridge. A bridge of this type could be used to cross a lock on the canal proper. If a public road were to cross a lock, like the one planned for Edwards Ferry, Wright would position the pivot bridge over the center of the lock chamber. If, however, a permanent structure were planned, he would locate the abutments below the lower gates to the lock.2 (A thorough search of the C&O Canal Company files at the Na- tional Archives has failed to turn up a copy of Judge Wright's plan for a pivot bridge.) Figures as to the comparative costs of the pivot and permanent bridges were studied by the Board of Directors, and Judge Wright was directed to devote additional thought to the subject. 3 Judge Wright moved slowly. It was October 20 before he notified President Mercer that he was currently preparing a memorandum for submission to the Board on the subject of bridges, culverts, and roads. All that he had seen and heard had strengthened his view that the fewer bridges across the canal the better. Any bridges that were necessary should be movable. Since this idea was “novel” in its character, considerable thought would have to be devoted to “devising the best plan” for the proposed pivot bridges.4 (Unfortunately, 1 Mercer to Fairfax, Nov. 12, 1828 (Ltrs. Sent, C&O Co.). All manuscript source materials re- ferred to in this report are deposited in the Department of the Interior files at the National Ar- chives and Records Administration, College Park Annex, and are designated Record Group No. 75. 2 Wright to Mercer, Feb. 12, 1829 (Ltrs. Recd., C & O Co.). 3 Lee to Mercer, Feb. 15, 1829 (Ltrs. Recd., C & O Co.). 4 Wright to Mercer, Oct. 20, 1829 (Ltrs. Red., C & O Co.) 1 2 Bridges of the C&O Canal Introduction Wright's report, if made, cannot be located in the records of the C & O Canal Company on file at the National Archives.) At this time, the Board of Directors in its search for a plan for a bridge authorized the Treasurer to pay $10 for a model of one invented by General Walter Smith. 5 Thomas F. Purcell, who replaced Judge Wright as Chief Engineer, prepared the specifica- tions for permanent road bridges to be constructed across the canal above the Georgetown Level. According to Purcell's specifications: The excavation for the abutments and wings shall be I foot at least below the bottom of the canal and of such slopes as the Engineer may direct. The foundation timbers will be flattened upon 2 sides, 12 inches thick, and placed 2 feet from centre to centre, or closer if necessary. After the timbers shall have been properly laid, they will be covered with 2-inch plank, upon this foundation the abutments and wings will be erected which shall be built of ranged, ham- mer dressed, rubble masonry. The stone shall be of good quality and well laid mortar or grouted, or both, to six feet above the canal bottom, from which line to the top of the masonry common lime may be used. No course will be used in the work of less than 12 inches and no stone will be permitted to be used of less than 18 inches bed and end joints of 12 inches. The coping will be cut and sloped with steps of 12 inches rise and two feet tread measured on the inner curve of the wing—the steps shall lap on to each other 1 foot. The superstructure will be built of 2-inch white pine plank, 12 inches broad, framed accord- ing to the lattice form shown upon the plan [The plans to which these specifications were keyed have not been located], 3 rows of braces 2 1/2 feet from centre to-centre, bound to- gether with 4 sets of white oak ribs, the lower course of which shall be double: these ribs and the braces (which shall cross each other at right angles) will be connected together with Lo- cust pins 2 inches in diameter. On the lower course of ribs will be placed cross ttmbers 6 by 14 inches deep. These timbers will project 6 inches beyond the ribs and be notched into them 4 inches and will be braced by 3 by 4 inch scantling in the manner shown on the plano Upon the cross timbers will rest the string pieces which will consist of white oak timber 3 inches broad by 12 inches deep: these timbers will be notched 2 inches upon the under side where they shall cross the supporting beam so The flooring will be 3 inch white oak and secured to the string pieces by spikes or tree nails. The top of the lattice work will be covered with 3 inch plank leveled to 1 1/2 at the outer edges—this plank will project 2 inches beyond the up- per ribs and be secured to them by iron spikes.