Reclamation is unique in our large dams but we're not unique in the world.
There are other countries that have very large structures. A lot of these structures have concrete
thats made with aggragate up to 8 or 9 inches, like at Hoover Dam, or down to even maybe 3 or 4 inches
which is more standard for a dam.
But there's not a lot of ways to evaluate concrete that has that large of an aggragate in there.
Here in the materials lab, we can help evaluate the material properties of these large dams, for ourselves and for other entities,
and they, there really is nowhere else in the world for them to come to for these services.
Reclamation has long had an International Affairs program, probably going back to the 1950's. Essentially, Reclamation has a lot of
expertise in a variety of areas related to water resources management, dam safety, sedimentation,
planning, design and construction and these areas of expertise are not just well known
but desired and needed by another country's. Essentially Reclamation has, I'd say unique expertise
in the area of materials testing and that is recognized by a lot of folks in the U.S. and also in some cases oversees. In case of this program
right now we've got a dam that has a lot of rehabilitation needs, they want materials testing and so we've a fairly substantial program
like a six month program to look at a number of large samples to assess the safety factor.
We're working on a project where we look at a dam and its material properties. We are looking to determine
the strength of the concrete in both compression and tension.
So concrete is good in compression, thats when we basiclly squeeze the concrete in place and we would do that typically
on this machine behind me as our large machine up to five million pounds.
The compression tests we do on this large diameter cylinders are essentially the same as on a smaller typical 6-inch diameter specimen
that we use in everyday construction. We grind or cap both sides of the specimen to make sure that its plane and perpendicular
and we put it into our compression machine and load it vertically until failure.
We also test concrete in tension which is when you pull the concrete apart, and as most of us know you can walk on concrete
pretty easily, but we dont use it for tensile members very often because its very low in tensile strength.
Its those low strenghts that we really need to be estimating or predicting correctly
so that when we evaluate a dam on a whole we know that it will be able to withstand whatever tensile loads are put on the dam.
and that they don't exceed the strength of the concrete and that property which it is inherently weakened.
The Bureau of Reclamation is one of the world leaders in direct tension testing of concrete. Reclamations experience
Reclamations experience in doing this type of tensile testing has made it
possible for us to work not only on our own projects but on projects for other countries and other entities.
If other countries are interested in expertise and assistance from Reclamation, there's a variety of ways they could contact us.
It could be a letter to the commissioner, a very formal letter asking for assistance in the area
of need. It could be through an internet query, or contact the Reclamation employee at a conference.
In general of through formal, but we have occasionally informal request for assistance.