a contractor’s perspective on geotechnical education

A Contractor’s Perspective on Geotechnical Education

2009 Professors’ Driven Pile InstituteUtah State University

Logan, Utah

2009 Professors' Driven Pile Institute

Starting Point“Virtually everything I know about piles I

learned after graduation.” “It’s true that you never have to learn

something so well as when you have to teach it.”

“There’s always more to learn. I tell clients, if a geotechnical engineer tells you that they know everything there is to know about piles, show them the door. The one who says it seems there’s always more to know is the one to hire.”

Van Komurka2009 Professors' Driven Pile Institute

Education - IssuesContractor Comments

West Coast contractor noted they had interns and a recent fulltime new hire not understand how to use a tape measure or any basics of layout. They lacked knowledge of drafting & how to read a set of drawings.

The new generation can run a computer, but they don’t want to get dirty, which to me means they aren’t being exposed to practical applications of the subjects that they are required to take.


Education - IssuesContractor Comments

It seems disturbing that some engineering schools have dropped surveying all together (i.e., UC Berkeley). Contractor (also PE) was required to take 2 semesters of surveying. How can you build or design something if you don’t where to put it or tell someone where it goes?

Some universities are training engineers to be graduate students and then professors.


Education - ObservationsLack of practical knowledge

Not unusualMitigation Methods

Internships Invite industry professionals to visit classes Contact industry professionals to arrange for site

visits Develop working relationships with local

engineering and construction firms to provide additional resources and mentors for students


Practice - ObservationsYoung engineers need mentors within the

professionNeed to stay at one place long enough to

really learn their professionIt takes time and effort to learn the

peculiarities of a particular aspects of a profession.

It takes time and effort to learn the peculiarities of a given region.


PracticeBe informed. Engineers need to visit the site

prior to design to ensure what they are designing is practical and can be constructed. Know your options.

Select and appropriate pile for a particular site . Know what materials are available.

Beware the catalog engineer!


Frog Pond Apartments


PracticeBe realistic. We are driving piles to their

maximum capacity (with at least a 2:1 safety factor) then only using a portion of that capacity, particularly when setup is not factored into the design.

Design for what is needed, don’t overdesign unnecessarily.

Don’t compound safety factorsBe reasonable. Don’t make the pile hammer

the weak link in the system. Why are we driving to 20 bl/in?


PracticeThe motto is “A driven pile is a tested pile” not

“Every driven pile is a test pile”. Establish a driving criteria and let the

contractor do his job.Changing the rules after the contract is

signed costs money.


Cape Canaveral Hospital


Cape Canaveral Hospital

Cape Canaveral Hospital Had previously driven hundreds of piles at this same

site with the same geotechnical engineering firm. The soils are highly dependent upon setup.

Structural design predicated on geotechnical report that recommended a design allowable capacity of 50-tons for HP14x89 piles, 110’ to 115’ in length. This was based on static analyses using SPT-97.

Conducted three PDA’s, a 7-day re-strike with PDA and a successful, 100-ton static load test to 2x design capacity .


Cape Canaveral Hospital Engineer could provide neither definitive answer

nor immediate reviews of driving information . He still wanted to prove setup on each pile using re-strikes.

Suspect lack of experience/knowledge led to overly cautious approach and slowed responses to questions, which delayed completion and increased costs.


PracticeWhat are the design objectives?

What are we trying to accomplish?To drive each pile to the bearing capacity

required by the structure?To maximize the capacity of each pile based

on the geotechnical report?To drive to refusal?


PracticeGeneral lack of understanding of

geotechnical work and the unknowns with which we work among owners and general contractorsMost GC’s and Owners do not differentiate

between trades – everything is a commodity To an Owner or General Contractor the number of

piles driven in a day is similar to the number of bricks laid in a day.


PracticePush for adequate testing to determine

reasonable expectations. Uncertainty leads to higher cost.Driven piles compensate for uncertainty of

subsurface conditions. You pay for what is needed to meet job requirements.


PracticeOften deal with limited information

Owners might not want to pay for full design.Owners might only want to pay for minimal

subsurface exploration.No consideration given by Owners beyond the

immediate objective.


Glynn County, GA Outfall


PracticeMany construction claims pertain to

subsurface conditions.Owners need to understand that the more

that is known about site and subsurface conditions, the more the report can be used to accomplish and the more reasonable the construction cost estimate will be. An incremental investment in exploration can pay big dividends.


PracticeDesign-Build contracts are becoming more

prevalentEngineers need to improve their relationships

and familiarity with contractorsImprove the relationships between professional

associations. Dual memberships Programs of mutual interest


PracticeAcknowledge the potential for pile setup.

Educate owners and structural engineers regarding the potential cost and time savings derived from pile setup.

An early investment in testing can provide benefits

Once a project starts, time and cost pressure do not allow for full exploration.


PracticeAre engineers doing the best job for their

clients?Engineers cannot be all things to all people.Have found that there are a number of

structural engineers that do not have a good understanding of soils and geotechnical design. They tend to select a pile from a geotechnical report like they would a column from a steel manual - by column and row based on bearing capacity, which is usually determined by static analysis methods.


PracticeGeotechnical engineers are concerned about

the commoditization and marginalization of their profession. They explore and analyze soils and are paid to make recommendations. They provide information to structural engineers who design the foundation or retaining wall.Not enough communication between

geotechnical engineers and structural engineers.

Some geotechnical engineers prepare a report for an owner and never hear from the structural engineer.


PracticePoor or expensive designs resulting from lack

of experience or limited information increase costs and/or lend themselves to contractor innovationGood for the contractors in that we can use our

knowledge and experience to get workNot conducive for good, long-term between

engineering firms and their clients


PracticeRetaining Wall Contractor Comment

regarding H-pile and lagging systems: In the 70’s he used 3” lagging. Lagging has steadily progressed to 4”, 6” and in some cases, 8” thick. Either the soil has become worse or the designs have changed.


PracticeIt is not uncommon for a structural engineer

to rely on a geotechnical report to provide the “specifications” for pile installation. This practice highlights the gap between the recommendations in the geotechnical report and the decisions/non-decisions on specifications made by the structural engineer.

Contractors need to know the specific requirements of the project and we are to get paid.


Orange Avenue Apartments


Orange Avenue Apartments02350 DEEP FOUNDATION SYSTEMSInstall deep foundation units or systems only under the

direct supervision of the owner’s Geotechnical Engineer . Load Test Report shall verify assumed capacities or

foundation may be subject to redesign. Contractor shall review the Geotechnical Engineer’s Report

and follow its recommendations. The Geotechnical Engineer will report on the conformance of

the installation to the specifications and the capacity based on in-situ conditions encountered during the installation. Structural Engineer will review the reports and, at contractor expense, will recommend remedial action if necessary.


Orange Avenue ApartmentsFoundation Plan Notes: Steel “H” – piles shall be installed

per Geotechnical Report. All piles shall be HP12x84 with design capacities of 58 tons compression & 19 tons uplift. Provide load test to confirm design capacities. Pile splices shall be fully welded.


Orange Avenue Apartments 10.2 H-Pile Recommendations In order to provide the necessary load carrying capacity, we

recommend that the steel H-piles be embedded to a tip elevation of -35 feet NDVD, roughly 110 to 115 feet below existing grades. Below is a table showing the estimated allowable compressional and tensional capacities for single H-piles with a tip elevation of -35 feet NGVD.

Table XEstimated Pile Capacities for H-Piles

• Capacities are based on a factor of safety of 2.0 for compression and 3.0 for uplift


CapacityH-Pile Capacity (tons)*

HP10x57 HP12x84 HP14x117

Compression 41 58 80

Uplift 15 19 23

Orange Avenue Apartments10.5 PILE DRIVING ANALYER (PDA) AND

OBSERVATIONWe recommend that all piles be driven under the full-time

observation of a representative of [the geotechnical engineering firm]. Further, we recommend the use of dynamic pile testing, commonly referred to as PDA (Pile Driving Analyzer) testing. The recommended factors of safety of 2.0 (compression) and 3.0 (uplift) included in the allowable capacities provided in Table X are based on the use of PDA testing. Where the pile testing program consists solely of selected static pile load tests we recommend applying a factor of safety of 2.5 against the ultimate capacity in compression.


Orange Avenue Apartments10.8 QUALITY CONTROLFor H-piles and pipe pile, several test piles should be initially driven at

various locations over the site. Their driving should be carefully inspected by a geotechnical engineer and the driving log recorded. A Pile Driving Analyzer (PDA) should be utilized on each pile to monitor and record pile capacity during driving. Afterwards, at least two (2) piles should be selected for a full scale load test in accordance with ASTM D – 1143 to confirm the driving criteria ten (10) days or longer, after installation in order to negate the effects of pore pressure build-up during pile driving. The load test should be taken to at least three (3) times the pile design capacity, or failure, whichever occurs first. By taking the test to 300% of design, it may be possible to increase the allowable pile capacity and save a great deal of money by reducing the number of piles required on the project. We recommend that a PDA device be utilized for all of the production piles. Further, driving should be inspected and driving record maintained.


PracticeASFE – Marginalization and commoditization

have surpassed loss prevention as the most critical business issues challenging the welfare and survival of the geoprofessions.


PracticeDiscussion topic at the recent Geo-Council

Meeting regarding retaining walls:According to the SEI, Structural Engineers believe

any wall design should be done by a certified Structural Engineer registered separately from Civil Engineers. Since they are not likely to spend years studying the ground and observing the performance of the walls, they wish to use code-driven design methods, particularly LRFD. All they require from other engineers, such as geotechnical engineers, are design values, preferably design values taken from standardized tests.


PracticeThis has the potential to reduce other civil engineers,

such as geotechnical engineers or foundation engineers, to technicians serving the Structural Engineer, instead of a team of civil engineers with different specialties working together. The party that knows the least about the ground, which is the controlling factor, will assume legislated dominance over other civil engineers. Why should Structural Engineers assume that given a few design values they should be the only area of civil engineering that can act as the lead professional in a deep excavation, a landslide prevention wall or the underpinning of a building.


PracticeGeotechnical engineers need to engage now

and demand greater input into foundation design and retaining wall design.

Consider a greater partnership between geotechnical and structural engineers in foundation design or consider Foundation Engineering as a distinct discipline within civil engineering.


a contractor’s perspective on geotechnical education

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