Down to Earth

I was recently asked whether there is such a thing as the perfect in-situ soil test, probably in response to a presentation that I had given a few weeks earlier, in which I enthusiastically described the advantages of CPT. The answer is obviously no: there is no single test that provides the most reliable information on the various soil parameters for all soil types. Having said that, CPT is generally speaking a very appropriate testing method in soils other than rock and gravel, providing good data on a very wide range of soil parameters. As such it is clearly the most versatile in situ soil test available. What is even more important, especially here in North America, is that CPT provides information on more soil parameters than SPT in all soil conditions other than gravel. Moreover, for those soil parameters that can be derived from both the SPT and the CPT results, CPT provides generally more accurate results and the results are available within minutes after the test was done (before the test equipment leaves the test site). In other words, CPT is a very useful test to provide an all-around characterization of the soil in a very short period of time. Not perfect, but in my opinion by far the best in the class of in-situ soil tests.

In recent weeks we have spent a lot of time emphasizing the use of generic language in specifications. Far too often we see specifications where the author(s) seem(s) to have been at a loss trying to describe the functional requirements of a piece of equipment or a test. The easy way out in those cases is to mandate the use of a particular piece of equipment by including a brand name in a specification. The problem with that approach is that in doing so the author(s) in effect creates a monopoly or at the very least express(es) a clear preference for that particular piece of equipment. Especially for specifications issued by government entities this is not appropriate and quite often even illegal, but above all completely unnecessary. In most cases there is a specification out there that describes the function of that particular piece of equipment or that test (ASTM international has published close to 12,000 standards) and a simple statement that equipment or a test in accordance with a certain ASTM standard must be used quite often will resolve the issue.

When it comes to foundation testing the same applies. ASTM D4945 (Standard Test Method for High-Strain Dynamic Testing of Piles), ASTM D1143 (Standard Test Methods for Deep Foundations Under Static Axial Compressive Load), and ASTM D7383 (Standard Test Methods for Axial Compressive Force Pulse (Rapid) Testing of Deep Foundations) are just a few examples of detailed functional specifications that are reviewed (and, if necessary, revised) on a regular basis to keep them up to date.

So authors of specifications for foundation testing wishing to fairly describe a CAPWAP or a Statnamic test using generic wording should just refer to the appropriate ASTM specification (ASTM D4945 and ASTM D7383 respectively). Contractors will then have the freedom to use any brand of equipment which meets those ASTM standards.

Let's assume that you want to see a doctor to get a diagnosis for a potential medical problem. When you make the appointment you get told that the doctor won't be able to see you (as a matter of fact, he is not even close to where you are), but instead a nurse will see you and run some tests on you. She will then forward the test results to the doctor and that doctor will then determine what treatment, if any, you need. I fully expect that you would not accept something like that, but you may be wondering why I am mentioning this.

The reason is that it is similar to a practice that is strongly promoted by some in the geotechnical industry: take the measurements during a Dynamic Load Test, send them to somebody who has never been on the job site, and that person will determine the capacity of the pile. To me that makes about as much sense as the example I mentioned at the beginning of this message. The outcome of a Dynamic Load Test determines whether a pile can be accepted as is, but in order to properly analyze the data you need to be fully aware of the local conditions, and that is impossible if it is done by somebody who has never set foot on the job site.

I'm sure that some of you disagree with the above and I look forward to hearing from you. Hopefully your response will address the need for awareness of local site conditions during a load test and how somebody far away could possibly have this knowledge, because that is really what this issue is all about.

As I mentioned in my previous blog with this title, the AFS30 committee of the TRB hopes to organize a session on this topic at the 2010 Annual Conference of the Transportation Research Board in January of next year. In the next few weeks a call for papers will be issued for this scheduled session that will focus on factors relating to the Use of Open Source Software for Foundation and Soil Testing, including:

As soon as I have details on how to submit papers, I will edit this post to incorporate them, but I hope that many of you will submit a paper with your thoughts on this issue.

Baziw Consulting Engineers, Ltd. (BCE) and Verbeek Management Services (VMS) announced that they have entered into a strategic alliance. Through this alliance BCE can focus their attention on product development and training of their clients in the use of that equipment, while VMS provides marketing and sales support, making full use of their extensive contacts, not only in the geotechnical service industry, but also in the oil & gas industry.

BCE specializes in seismic systems design, which incorporates seismic sensor instrumentation, signal conditioning, digital signal processing (DSP) and general software engineering. The company provides customized and state-of-the-art hardware and software solutions for a variety of seismic engineering applications in the geotechnical industry as well as in the oil & gas industry.

Erick Baziw, President of BCE, commented that he is very pleased with this alliance. “While we have developed and continue to develop a number of very sophisticated applied seismology products, our marketing and sales activities were often short changed in our desire to develop leading edge technology. Through this alliance we can be assured that this part of our business will get the attention it deserves”.

Commenting on this news, Gerald Verbeek, President of VMS, mentioned that it is another clear recognition of the services VMS can provide its clients. “This partnership between VMS and BCE is also a perfect fit, since BCE's products target two areas (geotechnical and oil & gas) where we are already very active, and this work will just expand our activities in those areas”.