Seven Mile Bridge, Linking Florida Keys, Knight Key, Monroe County, FL
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Linking Florida Keys, Knight Key, FL
Find maps of Knight Key, FL
Documentation compiled after 1968.
Survey number HAER FL-2
Building/structure dates: 1909 initial construction
Building/structure dates: 1938 subsequent work
Significance: At the time the Florida East Coast Railway constructed this bridge it was acclaimed as the longest bridge in the world, an engineering marvel. It was the most costly of all Flagler's bridges in the Key West Extension. Since the beginning it has served as the one and only vital link between Miami and Key West. The logistics of assembling labor and materials and overcoming the difficulties presented by deep water, normal tides and hurricanes attest to the engineering and management skills of those connected with its construction.
American Bridge Company
Coe, C. S.
Duncan, B. M.
Krome, William J.
Meredith, Joseph C.
Historic American Engineering Record (Library of Congress)
1. General elevation view, facing east.
2. General elevation view, facing west, closed position.
3. General elevation, closed position showing fenders.
4. General elevation, 3/4 open position, showing circular center bearing and super-structure.
5. General elevation, open position, showing circular center bearing, super-structure, operators shed.
6. Typical Fender
7. General view of south abutment connection, also showing fender construction.
8. Barrel shot, facing south.
9. General deck view, showing vertical, diagonal, sway and upper lateral bracing.
10. General deck view, showing steel grating deck, posts, diagonals, upper chords and lateral bracing.
11. General view of floor beams, stringers, and lower lateral bracing systems.
12. Detail of center compression posts, and vertical shaft drive train for operating jacks.
13. Turning shafts, worm gears for operation of lifting or lowering jacks.
14. General view, showing upper chords, lateral and sway bracing, facing north.
15. General upper view, showing upper chords, lateral and sway bracing, racine south.
16. Detail view of upper portal chord connection.
17. Detail view, upper chord connection, beginning of second panel.
18. Detail view, upper chord connection, beginning of third panel.
19. Detail view, upper chord connection, end of third panel and the start of the central superstructure.
20. Detail view, upper lateral bracing.
21. Detail view, upper tension strap connection in central super-structure.
22. Operating equipment: Hand wheel for control reversal, stick shift for jaw clutches, indicators for the turning of the bridge, and raising/lowering jacks, jaw clutches for bridge and jacks, jaw clutches for bridge and jacks.
23. Brake, bridge turning shaft, shaft bearing.
24. Operating equipment, turning shafts and worm gears for raising and lowering jacks.
25. General interior view of operators shed facing east. Turning shaft for bridge, brake, bearing.
26. General interior view of operators shed facing west, showing operating equipment
27. Knight's Key Bridge looking toward Miami from point west of Knight's Key Dock (WRH-63, W-1).
28. Moser Channel Draw, N. abutment pier (WRH-214, W-5).
29. Moser Channel Bridge at joint W/concrete arches of Pacet Channel Viaduct, (WRH-277, W-9).
30. Knight's Key Bridge, erection of first steel span on to concrete pier, 21 August 1909 (W-12). See also H-25.
31. Knight's Key Bridge, lifting wood forms for piers on to concrete foundation (W-13).
32. Knight's Key Bridge, span No. 36 at crossing over Knight's Key Dock trestle (W-16).
33. Moser Channel Draw w/steel framing (WRH-215, W-20).
34. Moser Channel Draw, open w/construction barges and fender (W-21).
35. Moser Channel Draw, close-up, open (W-23).
36. Moser Channel Draw, close-up of steel bridging (W-25).
37. Moser Channel Draw, setting cofferdam for pivot pier (W-27).
38. Moser Channel Draw, pivot pier under construction w/steel reinforcing (W-31).
39. Moser Channel Draw, view down into wood form work for center pivot pier w/steel reinforcing (W-35).
40. Moser Channel Bridge, details of Pier # 174, drawing 12-23-1910, Rev. 2-21-11 (Dwg B-289).
41. Moser Channel Draw, details, Concrete Support for fender, 8-2-09 (Dwg B267).
42. Moser Channel Bridge, details of End Pier for Draw, undated, (Dwg 258).
43. Moser Channel Bridge, details of Center Pier for Draw, 7-3-09 (Dwg B-262).
44. Knight's Key Bridge, View of steel girders in place and on barge (#571).
45. Knight's Key Bridge, 3 horizontal views of construction. (#2492).
46. Knight's Key Bridge, view of driving pilings in cofferdam (#1771).
47. Knight's Key Bridge, No. 8 Cofferdam for abutment (W3137).
48. Knight's Key Bridge, finishing concrete piers w/view of temporary wood trestle in right (#2534).
49. Knight's Key Bridge, upper pier forms in position and derrick barge No. 96 (#355 A).
50. Knight's Key Bridge, view of cofferdam on barge (#4323).
51. Knight's Key Bridge, view of first span, 1909 (#2518).
52. Long Key Viaduct, view showing typical method of construction for all concrete arches in 7-Mile Bridge (#214).
53. Knight's Key Bridge, view of derrick lowering cofferdam (Lindenberg Collection #1569).
54. Moser Channel Bridge, View of upper steel framing of draw span, 12-22-26 (Matlack 131-40).
55. Moser Channel Bridge, view of tracks through draw span, 12-22-26 (Matlack 132-40).
56. Moser Channel Bridge, view of upper steel framing of draw span w/tracks receding in distance, 12-22-26 (Matlack 133-40).
57. Moser Channel Bridge, close-up of draw span partically open w/detail of operator shed, 12-22-26 (Matlack 134-40).
58. Knight's Key Bridge approaching Pigeon Key, 12-22-26 (Matlack 138-40).
59. Knight's Key Bridge, long side perspective, 12-22-26 (Matlack 141-40).
60. Typical concrete arch viaduct, 12-22-26 (Matlack 146-40).
61. Moser Channel Bridge, draw span, Oct 5-6, 1937 Matlack 282-13).
62. Construction view of concrete bridge meeting railroad bridge, 10-28-37 (Matlack 247-13).
63. Pigeon Key Bridge, construction details of method for adapting bridge into highway. Oct. 5-6, 1937 (Matlack 287-131).
64. Pigeon Key Bridge, view of riveters widening bridge for highway, Oct. 5-6, 1937 (Matlack 288-13).
65. Copy of drawing of Part Section Through Roadway, Nov. 8. 1937 (Matlack 322-13-1).
66. Pigeon Key Bridge, aerial view w/auto traffic, April 23, 1938 (Matlack 397-13-7).
67. Overseas Highway, wooden bridge between Key Largo and Mainland, April 9, 1929 (Matlack 127-50).
68. Moser Channel Bridge, draw span partially open, no date (Kyle K-32).
69. Construction view of concrete piers, for arches w/exposed reinforcing steel, no date (79-46-4).
70. View of concrete highway bridge w/railroad tracks as guard rails, ca 1937 (X-664-10).
71. Post card, 'Side By Side, Railway and the Highway Span the Keys', no date (Perez donation
72. Knight's Key Bridge, passenger train crossing bridge, no date (Bramson Collection, X-336-1).
73. Seven-Mile Bridge, view of tracks on concrete base, no date (Perez donation K-579).
74. Plans of Proposed State Highway, Key Map.
75. Plan and Elevation, P a c e t Channel Dwg #81.
76. Plan and Elevation, Pigeon Key Bridge, Dwg #83.
77. Plan and Elevation, Knight's Key Bridge, Dwg #84.
78. Plan and ElevatiOn, Moser Channel Swing Span, Dwg #115.
79. Layout of Lateral and Floor System, Moser Channel Swing Span, Dwg #116.
80. Plan and Elevation, Moser Channel, #? (See FM-3).
81. Fender Details Bridge No. 20 over Moser Channel, #?
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