bike/hike trail engineering

[mdk]

We design trails and often work with non-profit groups that do not have the money to spend on DOT type engineered trails (i.e lots of cross-section, vertical alignment along length, etc). I would like feed-back on the problems associated with designing in this fashion and suggestions for notes, details and specifications that can be added to allow contractors to be able to bid the project and to insure a well constructed trail. My concerns include how the contractor calculates cut/fill, how I can be assured the trail flows well in the vertical profile, etc. Some of the things we do now are draw plan layouts with stationing to give contractors an idea of length and typical cross sections to give them an idea of the profile expected, often noting follow existing grade and raise trail surface elevation 6 inches above surrounding grade. I note all vertical curves to be smooth and continuous, and that exact layout be field verified. I add a detail for drainage pipe under the trail and indicate a few areas I project that these will be needed and field adjust this number. I know this is not ideal way to design a project but I also like to remember that they are trails and not roads. Thank You

 

[BigH]

This is a bit like designing haul roads for forestry. (They do have the money - just don't want to spend it.) I would say that your approach is a reaonable one - I would specify max grades for vertical profiles. Can you get topo maps of area? (see thread in this group) If there is a university nearby, check with their surveying department and see if you can hire a couple of bright students (nominal charges I would guess) to do a preliminary layout - it would be great practice to them; the prof might even do this as a class assignment of the real world rather than do the "arts quad" for the umpteenth time. This could give you the data needed to estimate the quantities for the work. Require the Contractor to issue working sections and profile for approval prior to starting the work - they don't have to be elaborate. You will require him to give "as builts". To pay him you need this for checking the quantities. One thing I worry about is the need for small retaining walls in cross-cuts and fills. You should have a few standard sections for small crib walls, etc.

Hope this helps.

 

[bridgeboy]

When you say you would like feedback, does that mean you've had problems with your approach?

How do you bid a job like you describe?

I think your approach is a good one, providing you've got a good "Resident Engineer".

It wouldn't fly here in California anymore. Too many lawyers.

 

[MikeDB]

Does the National Park Service, Corps Of Engineers or National Forrest Service have design guides for this sort of thing?

 

[Rich2001]

Engineering and CAD details from DISTRICT 9 U.S. Forest Service

http://www.fs.fed.us/.ftproot/pub/acad/

 

[KRSServices]

Roots, Roots, Roots! Your general approach seems reasonable for the construction of the paths. Specify the surface, the strippping and any other parameters you want done. In bidding, the contractor has to view the site and then prescribe the unit bid or lump sum tender. I've used both without too much problem in these cases.

Word of caution, in wooded areas, particularly with poplar (or vegetation with sucker roots) sterilize the soil or provide barriers to the roots! Those things have a nasty habit of migrating between the base and the ACP surface and causing all sorts of problems (spped bumps). Also, if thin ACP is used, ensure the base material has been sterilized. I had about 2 kms of newly placed trails (ACP) fail due to the base gravels being infested with dandelion seedlings (prior to placement) and in the spring the surface were bulging with little speed bumps due to the plant pushing through to the surface! It was ugly!

Finally, if your area is susceptible to freezing, ensure the drainage pipe is sufficiently constructed to prevent failure to the path due to heaving. KRS Services

http://www.krs-services.com

 

[BigH]

Just as a follow up on this thread, I was searching the net on another topic but ran across the site below which deals with design concepts, etc. for park trails:

wlap

http://www.gov.bc.ca/bcparks/operations/facstand/trails/t-trailconst-6.pdf

Might be of interest to MDK and others.

 

[rmccabe]

We provide non-corrosive structural fibers for concrete reinforcement, and some engineering support for projects. We have built many roads, railways, etc. without steel, and many in conjunction with steel, depending on the requirements. I would be happy to work with you to meet your requirements.

The fibers are PVA (polyvinyl alcohol) and are well documented in the academic press:

http://www.engineeredcomposites.com

Free samples are available.

Richard McCabe
Senior Advisor
Kuraray America, Inc.
707-824-8375

http://www.kuraray.co.jp/pvaf/english/index.html