Memorial Bridge closure?

[mstone]

@Steve O 117012 wrote:

You learn something everyday: I had no idea that Memorial Bridge was a drawbridge.

Does it still count as a drawbridge if it’s rusted shut?

[Vicegrip]

@mstone 117022 wrote:

Does it still count as a drawbridge if it’s rusted shut?

55 gallon drum of liquid wrench and a putty knife?

[kcb203]

@worktheweb 117014 wrote:

I would love to hear the engineering explanation for reducing or eliminating the pedestrian and cyclist lanes on the bridge.

If we assume that the average pedestrian or cyclist is 200 lbs (I’m being generous, it would likely be less than that) and take google’s assumption that the average weight of a car is about 4,000 lbs we can start thinking about this numerically. For every one car you allow on the bridge, you could have 20 peds/cyclists. They’re keeping 4 our of 6 car lanes open. Using google again, the average vehicle is about 15 feet long. Let’s call that 20 with spacing in rush hour traffic. The bridge is 2,162 feet long. So each lane can hold something like 108 cars, at about 432,000 pounds. All 4 lanes come to 1.72 million pounds or the equivalent 8,640 pedestrians/cyclists. I’ve never seen anywhere near that kind of pedestrian loading on the bridge, ever. The max I’ve seen is maybe 50, which would be 2.5 cars. Clearly pedestrians are not the concern here.

I am all for not having a bridge collapse, but instead of knee jerk decisions these things should be thought through and the reasoning explained to the public that owns and is on the hook for the maintenance of the bridge. Personally, I like the idea of shutting it down to car traffic and allowing it to be a pedestrian/cyclist boulevard. Do that for a week and I bet you find some “emergency funding” to fix the issue. I just hope that they have it open for next winter, as it is one of the only safe routes to get into the district when there is snow.

During the Cherry Blossom 10 Miler race, there are probably a couple thousand runners on there at the same time. Still way below 8,640 you calculate above. It’s only a mile into the race and people aren’t spread out much yet.

[mstone]

@Vicegrip 117025 wrote:

55 gallon drum of liquid wrench and a putty knife?

I think it’s worse if it gets stuck open.

[scoot]

The usual figure attributed for roadway wear-and-tear is proportional to the 4th power of the axle weight. I don’t know if that changes when you’re specifically talking about bridges though.

[Bilsko]

@Amalitza 117017 wrote:

It would not be about structural integrity of the bridge, but about providing access for the people doing repairs, and keeping the public away from the work site. Curb lanes/sidewalks– the outer edges of the bridge– are where people and equipment will go to access the underneath. I’m not saying this can’t be done while also maintaining pedestrian access, but if there are restrictions, that will be the reason, not the weight of the people walking across the bridge.

Its odd then, that they’re planning to close of the 4ft of sidewalk *closest* to the vehicle lanes. Then you’re forcing foot/bike traffic to transit on the section closest to the edge of the bridge….which is exactly where work crews will need access to get over the side and underneath. Unclear how that will work. @Terpfan’s comment that it will probably be one side, then the other makes sense.

Can you imagine what this process is going to be like when they have to do work to Key Bridge like…next year.

Even worse – 14th St bridge (George Mason Bridge). With only about 8 ft of trail on the one side, there’s no way bike/ped traffic would be successfully re-routed.

[Mikey]

just allow only pedestrians and bikes and weight limits won’t be reached.

[Greenbelt]

I say forget repairing the bridge for heavy loads — there are nearby freeway bridges for that. Instead just fix it up enough for light non-motorized traffic.

A pedestrian bridge between the Mall and Arlington would be be amazing. Pedicabs, bikes, kites, rollerbladers, festivals. Street trees.

The first non-carbon-emitting bit of U.S. infrastructure, in the heart of our nation’s government. Sign me up!

[DismalScientist]

@Mikey 117043 wrote:

just allow only pedestrians and bikes and weight limits won’t be reached.

http://www.mercurynews.com/ci_20695952/day-golden-gate-bridge-flattened:rolleyes:

[TwoWheelsDC]

Pontoon bridge. Worked for the Persians….

[dbb]

@Steve O 117012 wrote:

I had no idea that Memorial Bridge was a drawbridge.

They made it a drawbridge so the Navy could dock at Georgetown. The 14th Street bridges rendered that issue moot for most boats now.

[Starduster]

Memorial Bridge is (still) an exceptionally well-disguised drawbridge. Found a photo of it open: http://cdn.loc.gov/service/pnp/thc/5a37000/5a37500/5a37532r.jpg

Bonus- another pic: http://en.wikipedia.org/wiki/Arlington_Memorial_Bridge#/media/File:Bascule_span_-_Arlington_Memorial_Bridge_-_2013.jpg

And another showing *why*: http://en.wikipedia.org/wiki/Arlington_Memorial_Bridge#/media/File:Rusting_framing_-_north_sidewalk_at_east_bascule_abutment_-_Arlington_Memorial_Bridge_2013.jpg

I am confused by all the posts- *someone’s* ridden it today. Is one sidewalk or the other open to ped/bike traffic?

[dasgeh]

To PotomacCyclist’s comment: NPS has known this bridge needed replacement for a long time. The planning has been in the works far longer than the Memorial Cure study. It was always keyed up ahead of the circle. The question is will NPS think ahead enough to integrate these two designs before the final work on the Bridge. WABA and I and probably many others urged them to in our public comments to the Circle project.

In fact, WABA has been working on pushing for protected bike lanes on the bridge in the final design. (i think they should be up the middle, ala PA Ave, but that means access only on the north side of the Lincoln and past Memorial Circle).

As we find out what’s closed and why, I’m pretty sure you’ll see efforts to open whatever is possible to cyclists (eg if the car lane closures are a load issue, you’ll see a push to allow cyclists in the closed lanes as long as crews aren’t working on them).

[oldbikechick]

I rode on the bridge in the morning and the evening. I was paying attention in the morning since I had read the articles and it was exactly as described. Towards the middle of the bridge – they have closed off one car lane on each side and about 4 feet of the sidewalk next to the car lane. There is still plenty of room to bike and get around pedestrians. I was only on the south/east side of the bridge but I think it was the same on both sides. In the evening I had completely forgotten about it and was thinking about something else and I know I crossed the bridge, but I have no recollection of it, so I don’t think it affected me much!

[KWL]

Shorpy has a great photo of the construction of the drawbridge portion: http://www.shorpy.com/node/6894

[Author]

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