CONDENSED FACTS ABOUT THE ST. JOHNS BRIDGE
MAIN CHARACTERISTICS OF THE ST. JOHNS SUSPENSION BRIDGE, PORTLAND, OREGON
Compiled by R. Boblow, Resident Engineer for Robinson & Steinman, Consulting Engineers.



1. Total length of bridge, exclusive of roads, up to west abutment3,833.6 feet
2. Length of Suspension Bridge: Main Span1,207 feet
2 side spans, each 430 feet 3 inches
Total2,067 feet
3. Length of east approach1,511 feet
4. Length of west approach, exclusive of roads255.0 feet
5. Length of west approach roads: North arm2,215 feet
South arm2,950 feet
Total5,165 feet
6. Clearance of bridge above mean low water: At center of main span205.0 feet
7. Width of roadway between curbs194.0 feet
8. Width of sidewalks40.0 feet
9. Height of roadway at center of main span above mean low water213.3 feet
10. Height of roadway at main towers above mean low water202.7 feet
11. Height of top of concrete river piers above mean low water60.0 feet
12. Height of main steel towers above concrete piers, to points of support of main cables289 feet
13. Height of spires on tower tops50.0 feet
14. Height of beacon lights on tops of spires above mean low water401.0 feet
15. Height of beacon lights above roadway at main towers190 feet
16. Number of main cables2
17. Diameter of main cables16 3/4 inches
18. Each cable is composed of 91-1 1/2 inch diameter twisted strands
19. Length of cable between end fastenings2,720 feet
20. Maximum tension in one cable4,250 tons
21. Breaking strength of cable12,750 tons
22. Maximum load on one tower from both cables6,700 tons
23. Maximum load on one main pier7,950 tons
24. Depth of base of east main pier below mean low water50 feet
25. Depth of base of west main pier below mean low water25 feet
26. Weight of east anchorage29,000 tons
27. Depth of tunnels for west anchorage80 feet
28. Maximum pull of cables on each ancorage8,500 tons
29. The highest concrete pier is the viaduct pier at the east end of the suspension bridge and is known as No. 10
30. Height of pier 10 above the ground150 feet
31. Cubic yards of concrete in Pier 10.3,934
32. Weight of reinforcing steel in Pier 10100 tons
33. Total weight of Pier 107,968 tons
34. Weight of one main steel tower1,250 tons
35. Total weight of structural steel, railings and miscellaneous castings for entire bridge7630tons
36. Total weight of cables, suspenders and cable bands1,410 tons
37. Total number of cubic yards of concrete for all contracts70,000


CONSTRUCTION CHRONOLOGY


Work begun.........................................................................................................September 3, 1929
Pouring for main river piers completed...................................................................April 8, 1930
Main tower erection completed.............................................................................September 1, 1930
Cable and suspender rope erection completed.......................................................January 2, 1931
Suspended steel erection completed, floor stringers and side span trusses riveted....March 24, 1931
Pouring of roadway slab completed.......................................................................April 18, 1931
Pouring of sidewalk slab completed.......................................................................April 29, 1931
Paving of west approach road completed..............................................................May 15, 1931
Bridge dedicated and opened to traffic..................................................................June 13, 1931
Total period of construction..................................................................................21 1/2 months