Bridge out on Wayne Andersen Bikeway (IE the trail in 4MR park in Alexandria)

[Steve O]

I did dismount when passing some pedestrians.

Well, that diminishes the whole value of the marsh they created. When you force them off the trail, it's more comical as they fall in the mud, and less likely to injure them. Win-win.

[lordofthemark]

I seem to recall one when the nature trail opened. I didn't stop to check on Sunday. I did dismount when passing some pedestrians.

Well, that diminishes the whole value of the marsh they created. When you force them off the trail, it's more comical as they fall in the mud, and less likely to injure them. Win-win.

I wouldn't want to introduce an invasive species into the marsh.

[Judd]

Took a peek at this yesterday. It appears that the decking is reinforced concrete with a layer of asphalt. The hole appears to be the result of the rebar rusting out. It doesn’t look like it’s going to be an easy fix.


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[peterw_diy]

Took a peek at this yesterday. It appears that the decking is reinforced concrete with a layer of asphalt. The hole appears to be the result of the rebar rusting out. It doesn’t look like it’s going to be an easy fix.

Rebar rusting out, perhaps aggravated by recreation and police staff driving over that bridge repeatedly? Recreation seems to use full-size trash compaction trucks to collect the bags from the few trash cans between the baseball and soccer fields, and for the past year or more it has been very common for one or more police SUVs to be parked by the elementary school and baseball fields -- I expect these are the same officers chasing folks off the trail after 10pm.**

Initially the damage was just a 6" hole; see this Alex311 case from May for a photo; I think it's subsequently been enlarged by staff investigating the problem. The initial hole lined up pretty well with where you'd expect automotive tire tracks. I'm no civil engineer, but the design does not look sufficient for motor vehicles -- the internal I beams are very beefy but there's very little material on top of them. I'm surprised to hear there was rebar, since from my recollection I don't think the concrete could have been much thicker than rebar. The visible cupping on the bridge suggests that it's been used (and degraded!) by autos for years; having looked in the hole I'm suprised that it held out as long as it did, considering the deck thickness. There seems virtually no support between the I beams so I imagine the old concrete provided virtually no strength, and merely served as a substrate to hold new asphalt in place while it cooled and hardened -- only because of the rebar was that decking able to support autos.

ISTM the City should just replace the decking with pressure treated lumber and perhaps not cross it with those big trash trucks (not that I've ever actually seen that happen). The I beams are close enough together that load shouldn't be a problem (the sagulator suggests even with I-beams 18" apart --and I think they're spaced closer than that-- the police should be able to cross safely even if the decking were made of generic 2x6s). A wooden deck would be less expensive to build than asphalt etc, easier to inspect, and might discourage parks staff from using the bridge as a shortcut when picking up 4MR park trash. Traction shouldn't be a concern since this is straight, short, in the middle of a > 90 degree turn, and with so many pedestrians that nobody should be racing across it.

** It seems some APD and RPCA staff consider these trails to be subject to the City ordinance that sets default "park" hours, which would mean use would be forbidden between 10pm and 5am.

[CaseyKane50]

Some signage has been installed.

[peterw_diy]

Yesterday I rode by there for the first time in weeks. The surface of the now closed bridge looks as it has since late May -- the damage doesn't seem any worse, they've just closed the bridge, forcing us to use the marsh route, which unfortunately is unlit and feels more cramped than it sometimes does because of foliage overhanging the trail. Anyhow, I wonder why the City closed the bridge entirely after two months of merely keeping people away from the damage. Does anybody know?

[mstone]

Yesterday I rode by there for the first time in weeks. The surface of the now closed bridge looks as it has since late May -- the damage doesn't seem any worse, they've just closed the bridge, forcing us to use the marsh route, which unfortunately is unlit and feels more cramped than it sometimes does because of foliage overhanging the trail. Anyhow, I wonder why the City closed the bridge entirely after two months of merely keeping people away from the damage. Does anybody know?

I'd guess an engineer looked at it and freaked.

[Judd]

I'd guess an engineer looked at it and freaked.

It looks like it got significantly bigger from the first time I saw it since the last time I saw it. There’s lots of kids around this bridge and the hole looks big enough that a kid could get hurt doing kid stuff around it.


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[peterw_diy]

There’s lots of kids around this bridge and the hole looks big enough that a kid could get hurt doing kid stuff around it.

Agree to disagree. The hole had been pretty effectively blocked with an impressive combination of cones, caution tape, and one of those steel barricades, and I've never seen unsupervised kids in 4MR park that weren't old enough to know how to stay safe around that kind of damage. "could" get hurt, I guess, but the same thing could be said of the 6" steep drop off the edge of the asphalt trail that remains open there.

[Judd]

Agree to disagree. The hole had been pretty effectively blocked with an impressive combination of cones, caution tape, and one of those steel barricades, and I've never seen unsupervised kids in 4MR park that weren't old enough to know how to stay safe around that kind of damage. "could" get hurt, I guess, but the same thing could be said of the 6" steep drop off the edge of the asphalt trail that remains open there.

Didn’t know they had barricaded off just the hole. This is what it looked like the last time I saw it before the bridge was closed.




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