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2009 Professors’ Driven Pile Institute Utah State University Logan, Utah 2009 Professors' Driven Pile Institute.

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Presentation on theme: "2009 Professors’ Driven Pile Institute Utah State University Logan, Utah 2009 Professors' Driven Pile Institute."— Presentation transcript:

1 2009 Professors’ Driven Pile Institute Utah State University Logan, Utah 2009 Professors' Driven Pile Institute

2 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 Komurka 2009 Professors' Driven Pile Institute

3 Education - Issues Contractor 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 Professors' Driven Pile Institute

4 Education - Issues Contractor 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 Professors' Driven Pile Institute

5 Education - Overview College Curriculum Overall, not much time to educate Good basic foundation Provide general civil engineering education Enough knowledge and tools to get started Limited exposure to driven piles and installation methods 2009 Professors' Driven Pile Institute

6 Education - Overview Specialization comes after graduation and in post- graduate studies Practical Learn while on the job Post-Graduate Studies Deep foundation design Driven pile design Research projects 2009 Professors' Driven Pile Institute

7 Education - Observations Lack of practical knowledge Not unusual Mitigation 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 2009 Professors' Driven Pile Institute

8 Education - Issues Engineering education cannot limited to the classroom Limited resources and other constraints have resulted in a reduction in the number of hours required to obtain an undergraduate engineering degree 2009 Professors' Driven Pile Institute

9 Education - Issues Really just enough time to explain the basics to undergraduate students What do you add? What do you cut? Where do you focus your efforts? Who instructs young engineers after they graduate? 2009 Professors' Driven Pile Institute

10 Practice - Observations Engineers have a lot of job options both within and outside of engineering. Specialties Structures, Transportation, Geotechnical, water resources and environmental Career Options Design, Construction, Management, Education, Research, Government, Private Sector 2009 Professors' Driven Pile Institute

11 Practice - Observations Young engineers need mentors within the profession Need to stay at one place long enough to really learn their profession It 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 Professors' Driven Pile Institute

12 Practice Be 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! 2009 Professors' Driven Pile Institute

13 Frog Pond Apartments 2009 Professors' Driven Pile Institute

14 Frog Pond Apartments 2009 Professors' Driven Pile Institute

15 Frog Pond Apartments 2009 Professors' Driven Pile Institute

16 Practice Be 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 factors Be reasonable. Don’t make the pile hammer the weak link in the system. Why are we driving to 20 bl/in? 2009 Professors' Driven Pile Institute

17 Practice The 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 Professors' Driven Pile Institute

18 Cape Canaveral Hospital 2009 Professors' Driven Pile Institute Cape Canaveral Hospital

19 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 Professors' Driven Pile Institute

20 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 Professors' Driven Pile Institute

21 Practice What 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? 2009 Professors' Driven Pile Institute

22 Practice General lack of understanding of geotechnical work and the unknowns with which we work among owners and general contractors Most 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 Professors' Driven Pile Institute

23 Practice Push 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 Professors' Driven Pile Institute

24 Practice Often 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 Professors' Driven Pile Institute

25 Glynn County, GA Outfall 2009 Professors' Driven Pile Institute

26 Glynn County, GA Outfall 2009 Professors' Driven Pile Institute

27 Practice Many 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 Professors' Driven Pile Institute

28 Practice Design-Build contracts are becoming more prevalent Engineers need to improve their relationships and familiarity with contractors Improve the relationships between professional associations. Dual memberships Programs of mutual interest 2009 Professors' Driven Pile Institute

29 Practice Acknowledge 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 Professors' Driven Pile Institute

30 Practice Are 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 Professors' Driven Pile Institute

31 Practice Geotechnical 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 Professors' Driven Pile Institute

32 Practice Poor or expensive designs resulting from lack of experience or limited information increase costs and/or lend themselves to contractor innovation Good for the contractors in that we can use our knowledge and experience to get work Not conducive for good, long-term between engineering firms and their clients 2009 Professors' Driven Pile Institute

33 Practice Retaining 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 Professors' Driven Pile Institute

34 Practice It 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 Professors' Driven Pile Institute

35 Orange Avenue Apartments 2009 Professors' Driven Pile Institute

36 Orange Avenue Apartments DEEP FOUNDATION SYSTEMS Install 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 Professors' Driven Pile Institute

37 Orange Avenue Apartments Foundation 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 Professors' Driven Pile Institute

38 Orange Avenue Apartments 10.2H-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 X Estimated Pile Capacities for H-Piles Capacities are based on a factor of safety of 2.0 for compression and 3.0 for uplift 2009 Professors' Driven Pile Institute Capacity H-Pile Capacity (tons)* HP10x57HP12x84HP14x117 Compression Uplift151923

39 Orange Avenue Apartments 10.5PILE DRIVING ANALYER (PDA) AND OBSERVATION We 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 Professors' Driven Pile Institute

40 Orange Avenue Apartments 10.8QUALITY CONTROL For 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 Professors' Driven Pile Institute

41 Practice ASFE – Marginalization and commoditization have surpassed loss prevention as the most critical business issues challenging the welfare and survival of the geoprofessions Professors' Driven Pile Institute

42 Practice Discussion 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 Professors' Driven Pile Institute

43 Practice This 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 Professors' Driven Pile Institute

44 Practice Geotechnical 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 Professors' Driven Pile Institute

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