tag:blogger.com,1999:blog-20029943.post8544030224588634405..comments2024-03-19T17:30:43.706-07:00Comments on cyclotram: Pics: Thurman Street Bridgebrx0http://www.blogger.com/profile/17988772767222837140noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-20029943.post-32778821913569678832016-09-03T08:52:52.443-07:002016-09-03T08:52:52.443-07:00Bridge was fully restored in 2014. (Fan of your b...Bridge was fully restored in 2014. (Fan of your blog.)BerkeleyMarxShermanhttps://www.blogger.com/profile/02913856655729118742noreply@blogger.comtag:blogger.com,1999:blog-20029943.post-44479437100315728172009-09-07T20:00:10.348-07:002009-09-07T20:00:10.348-07:00I think the critics of this bridge are being overl...I think the critics of this bridge are being overly dramatic.<br /><br />The one thing it really needs is a healthy dose of routine maintenance and a seismic upgrade.<br /><br />It has more than a chain-link fence for a guard rail. Yes, there is a chain-link fence (a very sturdy one, with lots of welded steel pipe as a framework to back it up) as a railing on the edge of the pedestrian walkway. But that's not the "guard rail", which is the white steel thing between the walkway and the roadway parts.<br /><br />So it's a wooden walkway, so what? Yes, you can see between the planks. Big deal. Nobody's going to fall through a gap 1/2" wide. The Hawthorne and Broadway bridges used to have such walkways before they were modernized; I'm glad there's at least one bridge with old-fashioned wooden sidewalks left in the city. I regularly walk across it (it's two blocks from my apartment) and don't feel frightened in the least.<br /><br />Those old streetcars were not "tiny"; they were quite heavy. Any bridge designed for them is up to the task of carrying trucks and buses, provided it is properly maintained.<br /><br />Today's bridge engineers use reinforced concrete as their building material of choice, primarily for cost reasons. Unfortunately, concrete (reinforced or not) does poorly in earthquakes. Every time a major earthquake hits a big city, the freeway network (with its many modern, reinforced concrete bridges) always seems to fare very poorly. Every time that happens, the engineers go back to the drawing books, modify their designs for reinforced concrete bridges a little, then pronounced the issues resolved. Until the next earthquake hits and nature again proves otherwise.<br /><br />The existing Thurman bridge uses structural steel, not reinforced concrete, which has proven to fare much better in earthquakes. Steel, unlike concrete, is not brittle and can flex instead of breaking when subject to unforeseen forces.<br /><br />In other words, a properly retrofitted Thurman street bridge is likely to be <i>more</i> earthquake resistant than a built-from-scratch brand-new concrete replacement.David B.noreply@blogger.com