BIKEPGH MESSAGE BOARD ARCHIVE

Wow. Driven by bees into an old trolley rut? That is about as ugly as you can get without having a driver involved.

Bees! Glad you're OK! But, this is fascinating - that is a bridge expansion joint, which means the road surface of Baum between the buildings is on bridge structure, not roadway on grade, with the buildings built tight against it. Or vice versa. That can't possibly happen too many other places. That is super fascinating from a nerdy arch/engineering point of view. Pittsburgh is amazing for that kind of stuff.

Oh, so that's what it is. That's exactly what it looks like, but since it's not a bridge I was baffled. It can't be a trolley rut - placement is wrong, and it's at least a foot deep. So glad it was early pm, sitting in the middle of the road is scary. Anyway, I got off lightly - didn't get stung!

BEES! http://www.youtube.com/watch?v=HbTiCdknEio

I assume this is the thing? http://goo.gl/maps/KR36b Glad you're ok, that is messed up... but now I am interested to hear the full explanation for this, I mean it's quite a long way from the visible bridge.

So bridges have to have an expansion joint at each end where they hit the ground, because bridges move. If a fly lands in the middle of a bridge, it moves. It may be too small to be measured, but it moves. If there isn't a joint to allow the movement, something will break, and it won't be the earth. If you look at Baum Blvd from the Center Ave bridge next door, what appear to be 2 - 4 story buildings is really 2 - 7 story bldgs. The bridge just shoots right between them at the level of the 4th floor. https://maps.google.com/maps?hl=en&ll=40.454642,-79.9428&spn=0.001233,0.002411&t=h&z=19&layer=c&cbll=40.454607,-79.942911&panoid=nh6KRX9yeVpJxTPOji1hEw&cbp=12,299.68,,1,-0.64 In Salty's picture, the black Mercedes is on road on ground, and headed onto the bridge. Or if you look at the aerial view, the bridge is all the way from the Baum/Morewood intersection to the first building at the edge of the valley. You can see the joints. You don't even see half the bridge. https://maps.google.com/maps?hl=en&ll=40.455121,-79.944436&spn=0.001241,0.002411&t=h&z=19 What is under your feet is not necessarily what you think it is. Also fyi I really REALLY dislike the Google maps default to the 45 deg view at a certain zoom level, very annoying. Pass that on Salty.

Glad you're OK, Naomi! Were you able to get the bike out and continue riding? No, I don't think the drain grates thread has this one. It should! How many others are lurking out there like this? This is fascinating on a couple of levels. * This is the first time I've heard of an expansion joint eating a bike. * I didn't realize that expansion joints could get that wide. * I never noticed that that corner was elevated * This might be the first documented case on the board of bees contributing to a wreck. Could someone get a picture of this joint when it's expanded like this?

Wait until it's 10 or 15 deg F out to get a pic, expansion joints will be at their widest. To drill down one more nerd level, :) , looking at Google streetview, you'll see that the joint on the Morewood end is a relatively narrow metal edged opening, but the joint on the east end is a wide rubber strip. My guess is that the engineers designed the bridge to push the majority of the movement to the east end, and minimize movement at the building end. This is a fascinating piece. The saw-tooth expansion joints on the 6/7/9th st bridges worry me much more. It's almost impossible to ride a line that crosses the opening at 90 deg. I usually try to ride in line with one of the "tongues" on those. And they're all steel, in the wet, scary as hell. I could also go into the various methods by which engineers accomodate the movement of the bridge ends, pivoting links, sliding pads, rotating wedges, etc. These are amazing little details of the world that you can see from a bike that you never see in a car.

Also technically Baum ate your wheel. lol.

Um, yes. But Morewood ate my wheel sounds better than Bee Baum :-) and anyone riding along Baum should sail straight over the gaps which are really only a problem for anyone forced off Morewood for whatever reason. Locusts, etc. Yes bike was rideable - all I had to do was twist the front wheel back normal to the bars - I never do up the handlebar stem 100% tight (more like 95%) just in case something happens, so maybe that's what saved the wheel. Couldn't believe my luck, spokes & rim are a bit scratched but it spins true. Some other weird scars on the bike though, big scratch on the fork just above the axle, and brifter tops scratched/partly smashed, it must have done a total nose dive. I was so lucky not to do the same.