[For this week's cover photo essay on Portland bridges, go here.]

So you love Portland bridges—but just how much do you really know about our spans? See how well you can answer these questions, provided by the bridge power couple Sharon Wood Wortman and Ed Wortman, authors of the 3rd edition of The Portland Bridge Book. See the answers at bottom.

1. Which bridge was designed in part by Joseph Strauss, chief engineer for the Golden Gate Bridge?

2.  Which is the only Willamette River bridge in Portland with bike lanes on its roadway?

3. Which bridge opens an average of 30 times per month, the fewest of all the movable bridges over the Willamette in Portland?

4. Which downtown Willamette crossing is the only bridge other than Marquam or Fremont designated for emergency vehicle use?

5. Which bridge is on a City Council-endorsed list to get a skatepark like the one under Burnside?

6. With 12,500 vehicle trips per day, which Willamette crossing is the least-used bridge for cars and trucks?

7. Which bridge looks like an arch but is actually a cantilever truss?

8. Which bridge cracked and almost fell down during construction?

9. Two railroad locomotives fell off of which bridge on New Year's Eve 1983, killing two trainmen?

10. In 1893, a streetcar fell off of which bridge, no longer standing, taking the lives of seven passengers?

11. Which bridge is supported by 1,200 Douglas fir tree trunks driven into the river bottom?

12. Which bridges are (or will be when finished) supported by concrete shafts 10 feet in diameter drilled deep into the river bottom?

13. Several spans of which bridge were raised in the 1950s to provide more clearance for river traffic?

14. Which two bridges were redesigned by others after the original designers and county commissioners ran into a legal difficulties over contracting arrangements?

15. Roadway decks made of fiber-reinforced polymer were recently installed on the lift spans of which two bridges to replace worn-out steel grating?

16. Which steel bridges have been built (or are being built) of weathering steel to save future painting costs?

17. Which bridge replaced the last ferry boat crossing in the Portland-Vancouver area?

18. On which four bridges does part or all of the roadway hang on steel cables?

19. Which lift bridge can't be opened without approval from Omaha, Neb.?

20. Which bridge was featured prominently in three Hollywood films?

21. How many students in the Portland Public Schools will study the city's bridges as part of the third-grade social sciences curriculum this school year?

For more bridge-related activities, check out www.willamettebridgewalk.com, where Sharon's bridge guide successor, Nathaniel Hoover, posts upcoming tours. Sharon and Ed will also hosting a special bridge tour Sunday, Oct. 27, to raise money for an upcoming children's edition of the bridge book, The Big & Awesome Bridges of Portland & Vancouver—A Book for Young Readers & Their Teachers

1. Burnside 
2. Burnside 
3. Broadway 
4. Burnside
5. Steel
6. Steel
7. Ross Island
8. Fremont
9. The Burlington Northern 5.1 swing bridge, now known simply as BNSF 5.1
10. Madison No. 1 (then located where Hawthorne now stands)
11. Northbound Interstate
12. Sauvie Island, TriMet Transit, new Sellwood
13. Northbound Interstate
14. Ross Island and old Sellwood
15. Broadway and Morrison
16. Sauvie Island, new Sellwood, and BNSF 5.1 (1989 lift span)
17. Sauvie Island in 1950 (before that, St. Johns in 1931)
18. Portland-Milwaukie Light Rail Bridge, Fremont, St. Johns, Sauvie Island
19. Steel
20.Broadway: Untraceable (2008), Bandits (2001), Foxfire (1996)
21. About 3,900