In a recent linked in poll, we asked the question who should design deep excavations and why. The motivation was the fact that in some states within the US, laws or statutes have passed that recognize only structural P.E. as the ones responsible for the design of deep excavations. The poll results above appear to indicate that the engineering community believes that an engineer should be familiar with both principles and that this requirement can only do harm. In fact, professional engineers by a margin of 58% indicated that a deep excavation designer must firmly grasp both geotechnical and structural issues.
So where does this leave us, should we have a new P.E. the F.E. for Foundation Engineer? We do not think that this is the answer. Clearly engineers should have experience in the field and should stay within their discipline. Perhaps it is better that for critical projects states require that an engineer's provide a track record of successful deep excavation designs. For this reason, a regular P.E. with a proven track record should be sufficient. This of course is not intended to discredit the value of S.E. of G.E. licenses. Each has something to bring, however, the overspecialization leads to complexities and unnecessary bureaucracy
Another major conclusion, is that, in most cases both disciplines will be present in a major deep excavation project.
I would like to personally thank all the engineers that have contributed to this very interesting discussion in our linkedin group.
Truly yours,
Dimitrios Konstantakos, CEO of Deep Excavation LLC, P.E.
Here are some of the actual comments
Seyed Shahaboddin Yasrobi • It is a great challenge between clients and designers.I do believe the most important part related to Geotechnical engineers ,whom has Civil base,specially when we use Nailing and anchors.The only system that may structural engineers are dominant is using piles (concrete or soldier piles).
Domenic D'Argenzio, P.E. • The behavior of underground structures and foundations are greatly influenced by the their interaction with the surrounding soils. Deep excavations fall into that category and the analysis of such structures requires a good working knowledge of both geotechnical and structural engineering principals. Soil pressures are a function of structure stiffness and often require an iterative process involving structural and geotechnical engineering analysis. Therefore, it seems logical that design of deep excavations requires an engineer well versed in both geotechnical and structural engineering practice and I would discourage the engineering community or any committee from advocating one over the other.
Bilal Kazi • The design should be designed by Geo-technical Engineer who have good Experience of Designing that type of structures at the surrounding Locations of related site or that type of soil. because it is very necessary otherwise after completion of project the chances of settlement should be take place it is very dangerous for structure & after that further treatment should be planned it will increase the Time & Cost of the Project. This is my Opinion Thanks for Reading my Opinion.
Philippe Fayad • Problem is that geotechnical engineers don't know how to perform structural designs and structural engineers do not understand soil behavior and water flow.
The question is: who is legally responsibility for the design of deep excavations? The Contractor, the Engineer, or the Owner? I would hope that in each case, both a geotechnical and a structural engineer are employed by the entity to design the works.
On final note: a lot of so-called geotechnical engineers are, to start with, structural engineers.
Michael Byle • Unfortunately, the legal requirement and the practical requirements do not always agree. Whoever seals the documents is responsible for the design legally. As with any multidisciplinary task, appropriate expertise must be applied and each project must be assessed to determine the appropriate expertise required. All geotechnical engineers will have had structural training and may have competence for simple structural issues, however, when it comes to detailing support systems and connections maybe not so much. Most all structural engineers have some geotechnical training, and their abilities may suffice for straightforward conditions such as uniform granular soils without water table issues. The problem comes when one gets familiar with simple cases and then attempts to fit other cases to a familiar approach. Some things are simple, and others not so. A significant professional challenge is being able to tell the difference, since one does not always have the requisite knowledge to appropriately assess the complexity of a situation.
Dimitrios Konstantakos • Dear Thomas, I agree with you that both principles are required. The issue here is that some states or cities in essence require a Structural P.E. for the design of deep excavations. My general feeling is that a regular P.E. well versed in both geotechnical and structural engineering is required. However, the requirement to only have a structural P.E. for the design of deep excavations does not take into account all the factors that are involved.
I can only bring an example of an very well known engineer that has over 40 years of design experience in deep excavations and the D.O.B. in Hawaii, if I am not mistaken, said that he could not stamp a deep excavation design because he did not have a structural P.E.
The general intention is to change the requirement to the previous status quo. That is, that a regular P.E. is sufficient as long as the engineer is practicing within his expertise.
Thomas Young, PE • Dimitrios,
I concur with you. Requiring special geotechnical or structural certifications omits competent and experienced regular P.E.'s. If a person has experience, then a regular P.E. is sufficient as long as the engineer is practicing within his/her area of expertise.
I suggest that thought to the requirements for over-specialization might be wreaking havoc to the engineering profession in that the pool of generalists capable of project integration spanning multiple disciplines might be shrinking. I see lack of project and engineering integration as contributing to failures that I examine in my forensic practice.
Some extreme examples of over-specialization are that some universities are eliminating thermodynamics from the civil engineering curriculum. All P.E.'s must have the education, experience, and intellect that equips them to go back to basic fundamentals in any situation.
Terence Holman, PhD, PE • I agree with Amr and all others who are advocating that knowledgeable, experienced "foundation engineers" should be responsible; not just a geotechnical engineer and not just a structural engineer. Geostructural engineers should be experienced in the rudiments of both facets of civil engineering. Unfortunately, there are now a growing number of state registration boards and legistlatures that have passed statutes disallowing anyone but licensed SEs from "designing" any sort of foundation, earth retention structure, etc. This is a very bad trend and will negatively impact the important business of foundation or geostructural engineering.
Mike Marasa, PE, BDM • It is obviously a problem that requires elements from both specialties for proper design. The interpretation of the subsurface conditions by an skilled geotechnical engineer will produce accurate loading conditions exerted by the soil, rock and water. The appropriate understanding of structural engineering will result in properly sized elements to create an efficient design. Inexperience in either discipline will produce an overly conservative and more costly solution, or much worse, a failure.
I'm most concerned with more recent graduates that know how to input parameters into a program without the experience or understanding as to what constitutes a reasonable result. If you don't get the model built right, it doesn't matter what the output says.
One step toward correcting this issue is to require a master's degree to practice the geotechnical specialty. A bachelor's degree seldom requires more than a fundamental soil mechanics class and a related laboratory. That is hardly enough theoretical background to correctly interpret a complex subsurface profile as it may relate to a deep excavation. I also echo the sentiment that field experience is a key component in proper professional development.
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