Bridges for Rural Areas 5

Look thru this website "USDA Forest Service, National Wood In Transportation Program". There is much information, all of it free.

Here are links to specific downloads:

"Standard Plans for Timber Bridge Superstructures"

"Standard Plans for Southern Pine Bridges", I am sure the plans could be adapted to other wood species.

"Timber Bridges: Design, Construction, Inspection, and Maintenance"

Best Wishes to you and your Country.

you probably need to start researching the price of steel vs concrete. Also if it is easy to get concrete (you can only haul fresh concrete not too long) to the rural area. If that was my research, thats what i do first before I do any engineering.

Thanks. This is very helpful.

Dear SlideRuleEra,
Any bridges made of Steel and/or concrete.

Regards
Clefcon

clefcon - Yes, there are. See "Bridges: Short Span Steel Bridge Plans and Software" from the American Iron & Steel Institute (unfortunately, the cost for the full version is $245).

The Portland Cement Association out-of-print document "Concrete Culverts & Conduits" includes typical designs for box culverts. However, the information is over 60 years old - reinforced concrete design has changed (improved) much since then - these designs most likely would not meet modern structural requirements. If you want to consider this publication as a starting point, you can download a .pdf copy from my website

There was a booklet of short-span concrete bridge plans published in the early 1980's - also by the PCA, I believe. It may not be this week, but will see if I can find it...

SlideRuleEra,
Thanks a lot.

Clefcon

Keep in mind the logistics and transportation of the materials.

Quality of timber may be an unknown item.

Steel will probably have to be fabricated and transported from Columbo and some of the roads could cause problems.

Concrete can be mixed locally, but the rate of supply may be limited somewhat. Depending on the volume, you could use the local traditional site batching systems similar to those used on apartments (5-15 story) in India. Normal 3000 psi should not be a problem since you have some good cement available and the rock is sound, if I recall correctly. Sand could be somewhat variable, but are local and determine the availability.

Sounds like an exciting subject.

Dick

Go to almost any State Department of Transportation web site and they will have standard bridge plans for both concrete and steel bridges. You will also find standard details for the substructure and alternatives like box culverts.

This is an australian proprietary product that may give you some ideas.

It uses timber beams and a concrete deck for just the type of bridges that you are talking about.

Dick,
Yes, one of my main concern is the logistics and transporation.

You're right. Sand is somewhat variable. Scarcity of river sand is high too. Contractors who operate close to coast use washed sea sand whereas river sand is available inland.

We have some problems with our available timber. We still use BS codes and our timber are not listed in most of published documents. Property tables are avilable but, not for all species.

Site batching is the only option if concrete to be used.

If soil conditions are not favourable and we need a concrete bridge (20'-0" wide for vehicular), driving a steel / timber pile is another chanllenge. Got any idea on that issue?

Regards
Clefcon

After you develop some preliminary concepts for bridge types you should run them past the local contractors. The guys actually building the bridges will be able to give you some good insight into what option is actually going to be cheapest/easiest to build.

Sounds like a great research project!