Deep Foundations Innovator Talks Load Testing
Since then, for nearly 50 years, Rausche has been immersed in the deep foundations industry. He co-founded GRL Engineers Inc. and Pile Dynamics Inc. in the early ’70s and was the president of GRL Engineers Inc. from 1977 to 2011. Rausche developed the CAPWAP and GRL WEAP programs, holds five patents and has had more than 50 papers published covering deep foundations.
Now officially retired from his functions as an officer, he’s still involved as a Pile Dynamics partner and board member, primarily carrying out an advisory function. This year the Deep Foundations Institute has selected him as its 2015 Osterberg lecturer. The annual Osterberg Memorial Lecture and Award was established in honor of geotechnical engineering pioneer Jorj O. Osterberg. It serves to recognize deep foundations innovations related to engineering design, testing or education.
Rausche will give his lecture, “Load Testing of Deep Foundations: Developments, Applications, Results,” at the 2015 International Foundations Congress and Equipment Expo (IFCEE) in San Antonio. National Driller recently interviewed the master of testing analysis and design about the lecture, the state of the industry and what’s next. Here’s what he had to say.
Q. How does it feel to be selected as this year’s Osterberg lecturer?
A. Well it’s a little bit scary. The previous honorees were very great researchers, very knowledgeable people in the industry. So I’m hoping I can make a contribution up to those standards. But yeah, it’s quite intimidating I must say, but it is also a great honor.
Q. What do you plan to discuss in your lecture and why?
A. Well actually, I was contacted by DFI to do this and I was asked to make a contribution that dealt with load testing. And of course that’s appropriate because Professor Osterberg, whose name this lecture is now being awarded had been very important in some of the developments of load testing, particularly of drilled shafts. So that is a subject, of course, that fits right in with the name of the lecture. My background is a little bit different and that’s why I can maybe contribute something about other areas of load testing — not just the Osterberg approach, which Dan Brown has recently been talking about in an Osterberg lecture. So he’s more knowledgeable in that than I am. But I’m involved in other types of load testing and so I will try to describe all of these methods, where they have their place and how they’re being conducted.
Q. What do you want listeners to absorb from your message?
A. For one thing, the industry today goes to higher and higher loads, to greater and greater structures, to bigger foundation elements. And at the same time we want to do things faster, more economical, more reasonable as far as how we use the materials. For that reason we have to do more testing and we have to try to develop structures that are, of course, safe but at the same time optimal. This is where these testing methods come in and that’s why it is good to have an understanding of what is available for testing and how it can be used, what it costs and how one could set up a testing program such that the outcome is, for all parties involved, economically optimal for the owner, of course, also assuring that he has a good product that’s what he expects and what he’s paying for.
Q. Aside from your lecture, what about IFCEE 2015 are you most excited about?
A. I call it the Olympics of the deep foundations industry. It’s something unique and it has been happening before but it seems to be more successful this time around. It’s just great to be involved and that our company itself will have several people there making contributions and, of course, being at the exhibition and attending lectures and so forth.
Q. You’ve been a part of the deep foundations industry for more than 40 years. How much have methods and technology evolved since your start?
A. If we think back to how John Roebling had to make the foundations for the Brooklyn Bridge, they had to dig down under high air pressures under terrible conditions to make foundations that are adequate. And how we’re doing it today with big machines, it’s much safer for everybody involved. It’s much more economical, too. There has been a big huge development going on. Not only is it safer and maybe more economical — what we are doing today. We don’t even have the time anymore to spend to make very elaborate foundations. We have to do it quickly. So that means that the whole design process has to be accelerated already in the initial testing phase that checks all the variable soils that we have to deal with right in the beginning so that we get an optimal design. But then we also have to make sure that the individual production piles or shafts are installed properly. So everything has to be, of course, done extremely efficiently and it is amazing what kind of drill shafts, for example, are being constructed today to what loads. In a way, this is only possible because of contributions like Professor Osterberg’s that allow for a reasonably efficient testing to very high loads of these individual shafts. All of these developments, design methods, installation of shafts and piles, testing of them and of course building a whole structure — that all had to be developed to greater and greater efficiencies. I think there will be further developments like that in the future.
Q. Have deep foundations applications and clientele changed?
A. We have different structures now that have to be supported by deep foundations. I’m thinking, for example, of the offshore wind turbines that have to be installed on very large piles. So they’re demanding larger and large pieces of equipment to do these jobs. Often the environment is very difficult. You have to very rapidly construct things often for uncertain and unknown foundation conditions. So there are new developments that create new clientele. As far as the existing situations like with bridge construction, for example, we have also seen quite a bit of development here spearheaded by the Federal Highway Administration, which recently changed the way we’re looking at safety concepts. So that also plays into the area of testing. In order to be able to reduce the factors of safety and make the foundations more economical, both testing and the factors of safety will now be linked to each other. The more you test, the more economical your foundation can be. So we have quite a few different ways of looking at things now, not only by the deep foundations experts, but also by the owners and all the structural engineers and the geotechnical engineers.
Q. What significance do testing and monitoring hold in the broader scheme of deep foundations installations?
A. This really goes back to what I just mentioned: the relationship between a safety concept. In other words, the structure has to be safely supported, even under extreme events, while at the same time it has to be economical. You cannot just make it super safe and spend too much money on it because there are too many uncertainties. So there are demands for testing not only to prove that a foundation element is sufficient, but also that it is not overdesigned and overly expensive.
Q. As a leader in industry research and education, what unknowns remain in the business of deep foundations that you’d like to better understand to better serve clients?
A. In my specific field, there’s still development to be done. My specific field has been dynamic load testing, which is more rapid than static testing. It saves time. But we have to do more development. For example, to test these larger and larger shafts dynamically, it’s not a simple thing. It requires larger and larger machines, but it also requires more research into how the elements behave under dynamic loads. We still have uncertainty on how soils behave under a variety of conditions. They are very unpredictable. They can even change over time. So there’s still a large field of research as far as the dynamic behavior of soils is concerned. Also how they behave in earthquakes, for example, or how we can model and understand them and their long term behavior. There are still many uncertainties. There are still possibilities for developing further tools for testing the soil, and even how the designs are being made. So there’s a huge area of research where we can learn to make our designs and structures more economical.
Q. Looking ahead, what are your hopes and expectations for the industry?
A. In the past, as mentioned, shafts and piles became larger and larger, took higher and higher loads. Eventually I think this is going to flatten out — that development. But at the same time we have to probably look more at how we can reduce the environmental impact. For example, everything that gets larger and larger requires more and more energy to make. In that regard we can maybe start to develop new systems that take less power, less energy and reduce carbon and still take the required large loads that we have to take for our buildings. So I think, in that regard, there is also a great area of research and development that even in the area of deep foundations is important. … In the future we have to work toward making this as sustainable as possible.
Q. What do you enjoy most about what you do?
A. Actually, some of the developments in our own field of testing devices, some of the software development we have to do. Also enjoyable is to go around and give a seminar on these things. In addition, we have a lot of young engineers and I’ve spent quite a bit of time telling them what I’ve learned and trying to help them understand. Some of these things are pretty complicated and that’s also an enjoyable part of my work.
Q. What’s next for you? Are there any new patents, publications or projects in the making?
A. Actually, we’re working on a new device to test the soils for just before a drill shaft is being installed. I’m always interested in working on a new way of making a more efficient testing or help in efficient construction. So there are a few things that we’re working on right now and this kind of research and development work is something I’m still involved with and I hope I can still make a contribution for a few years.