well... at IIT in Chicago, there are 2 new buildings that have to deal with this as one of the primary design issues.
Im guessing your familiar with the McCormick tribune campus center that OMA did. They address the issue by surrounding the El Tracks with a massive (and very, very expensive) tube structure.
This is definitely one approach.
Across 33rd street is the new dorms called the SSV, or state street village built by Murphy/Jahn. In that project they deal with the sound mostly through the placement of the program. All public lobby spaces, laundry spaces, stairs, mechanical etc are located on the wall directly next to the train tracks. So the residences are buffered from the sound of the train.

2 different approaches, both successful in their own way. The sound of the train running over the MTCC through the tube is barely noticeable, though the solution was exponentially more expensive than the solution offered by the SSV, which is also largely effective.

height is the critical factor- every 3 feet gives a 1db reduction or so... material doesn't really matter, as long as it's solid (no holes)- so glass, wood, concrete, corten, or seaweed doesn't matter.

depending on how tall the building is, you may need to project horizontally over the rail lines.

what about just sound proofing the facade facing the rail line? add acoustical windows, good sealant, and heavy materials- and you'll accomplish more for the guest's sanity then a simple wall.


good luck!

salut french! congratulations on your new and exciting project. I guess you're already familiar with ONL's sound barrier outside Utrecht?

Thanks lletdownl
I didn't knew about the helmut Jan project.
The oma project is great, but the program contained in the tube has different constraints than hotel rooms, which have to have views, natural light and such.
The approach of the SSV is in a way identical to ours (we have external circulations and sun screens that could almost be partially used to protect the room).
The other problem we have is that the site for the project is huge, and very nice if there wasn't the sound aspect of it. And we would like to protect it from this pollution as well as from others...
That's why right now we are not only focused on architectural solutions, but also on site/landscape solutions...

you can also build a berm...

treekiller
as I just wrote we also would like to protect the whole site from the sound.. Thanks for the detailed input on the height factor...

A-f, I know about this one... I'm not sure about the willing of our client to put so much money in that (I guess it's expensive isn't it?)

in addition to sound, you should probably look at isolating the structure from vibrations from the adjacent train track (if you havent done so already).

trees and plants will help a lot. Also, look at www.tectum.com . It is a green product

there is another sound barrier project in the netherlands that is pretty interesting... i think that it may be in utrecht... but i can't remember... it consisted of a series of townhouses built into the side of a berm... i can't recall the architects either... i know that i'm not providing much help... i'll try to find my sketch book from that trip and find the information...

french,

the architecture firm i work at is developing a sound barrier wall. we recieved a metropolis next generation runner up award for the idea. check it out here

thanks treekiller, I didn't know how to translate "merlon" in Elnglish... it's berm apparently

mdler brings up an important point...
the vibrations created by the rail line will render ineffective any means to dampen the sound if you dont limit their transmission through your site and building. In the OMA project at IIT for instance, the structure for the tube, the structure for the roof, and the structure for the train tracks are all buried at separate depths, isolated from one another and connected by beams which are also isolated as to minimize the transmission of vibrations. There was a real concern that the constant passing by of the EL would wreak havoc with partitions, flooring and especially window seals as well as being so noisy and obnoxious.

wow beefeaters, that's a great project!
too bad the images are so small... I'll get in the description and probably ask you questions about it if you don't mind... :)

and thanks for the concern about vibrations lletdownl, mdler...
we'll have to think about that further. We're not yet at the point where the structural system is clearly defined, so there's definitely room for improvement on this aspect...

thanks french!

id love to answer any questions you have. just let me know!

it should also me mentioned that the panes of glass in the SSV at IIT are not parallel. if i remember correctly, the outer panel faces upward a bit. supposedly both the shape of the cavity and the angle of deflection/reflection were supposed to help...

and i'm not a fan of the tube, i really think it is too loud... though the program almost welcomes the noise, and the train is incredibly loud to begin with (older(est?) parts of the elevated track.

how about those stacked concrete blocks with vegetation that you often see along the highways in germany? I can't seem to find a picture online...

beefeater- I'm curious about the actual performance of the sponge structure for 'absorbing sound' in an open environment. Has there been any large scale mock ups just to verify the sound control potential?

Also like dealing with air pollution, that will have some impact- but again need to see some scientific data/reports on the performance...

then there is the cost issue- most sound barriers are constructed by the lowest bidder and have minimal budgets- that's why most are prefab blah concrete or simple wood structures. the cellular structure seems more complicated to fabricate and the reactive coating is a second cost above the typical meager budget available for public infrastructure. Or is your firm marketing this toward the luxe private world?

Ok, found a picture. I love this kind of stuff:

treekiller- we are in DD phase now working on the sound performance of it. we will be building a full scale mockup to test the sound control by the end of this summer. we are using maya to generate forms based on a raytracing of sound waves made from a moving object (car) as they hit the wall.

the air pollution reduction has been proven. according to italcementi, the producer of the cement additive, if 15% of visible surfaces were treated with this additive, it would allow the reduction of pollution by around 50%. they have done numerous tests using it in italy. italcementi site
they did a test in milan and had considerably less amounts of pollution with the additive.

we are hoping to have these made as precast concrete structures. ideally, there is this new 3d concrete printer that we would love to use, but most likely wont be able to. otherwise, we are looking into fabric formworks, cnc milled reusable forms, etc.

cool!!!! keep us posted as to the results.

hmmm- is the wall porous or is the dimples/sponge texture a surface effect? if open, there may be potential savings available from the reduced wind pressure...

good luck!

thanks treekiller, i will.

the porous vs surface effect is what we are dealing with now. if it is porous then sound becomes a bigger issue. but we like the idea of it having these channels throughout, so we're trying to stay in that direction for now.

Oh gosh hold on guys...
The project will be on hold for three more monthes because of a stoopid administration guy not willing to do his job on time...
Therefore, we'll have three monthes to discuss this :(