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  • 1.  Geo and Structural Engineers - Collaboration Reality Check

    Posted 11-07-2018 11:39 AM
    Edited by Tirza Austin 11-07-2018 11:39 AM
    Last night, I gave a presentation to the SEI-MD chapter about how geotechnical engineers and structural engineers work together (to a room with an even split of both engineers). The lively Q&A and discussion afterward indicated that although we know we need to work together closely for the best project outcomes, it's currently very hit and miss. This seems to be partially for contract/liability reasons. For example, in building structures with an architect, the is often not part of the design team to the extent of other team members. Instead, the geotechnical report is "owner furnished" and under a separate contract.

    There was also a consensus that during the RFP process, neither the structural engineer nor the geotechnical engineer is getting the information they need from the other. We had one geotechnical engineer comment that RFP's are missing information. Another commented that trying to get accurate loads from the structural engineers was met with pushback. From the , we heard that some reports lack clear, unambiguous foundation recommendations. Or, that the geotechnical engineer disappeared from the project once the report was delivered.

    Although we as engineers may not always have control over the contractual part, we do have control over our levels of collaboration and how we interact with one another.  Why do you think we don't collaborate as much as we should? And, can you give any specific examples of things you have done on projects to improve this process/work better with your structural or geotechnical colleagues?

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    Stephanie Slocum P.E., M.ASCE
    Founder
    Engineers Rising LLC
    www.engineersrising.com
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  • 2.  RE: Geo and Structural Engineers - Collaboration Reality Check

    Posted 11-07-2018 10:12 PM
    Edited by Tirza Austin 11-07-2018 10:12 PM
    I had a slide that said the same thing in my presentation last night.  Design criteria needs to be shared between the design authority and delegated designer.  Both ways.  The design team or owner presents the initial criteria.  The delegated designer provides loads or impacts that result from analysis back to the design team for verification.  There needs to be dialogue at the beginning of the project and the end.  And yet, often the contract is limited in scope and schedule.

    Sharing of design criteria is vital.  It does open both parties to liability should the load or result being shared be incorrect.  Therefore, the sharing of this information needs to be documented.  The scope of responsibility for each party needs to be formally recognized at the onset.  Each party is responsible for their own work.  If it is based on data from others, a citation is necessary. 

    It's sad that the sharing of criteria is seen as a liability and not as a opportunity work as a team.  It's an opportunity to check each other's work and learn what the other disciplines are doing.  We should want to promote an open dialogue where someone is not afraid to raise questions or ask for information.  Your work is your own, but you have a responsibility to keep an eye others to keep the job site and public safe.

    I can't say you won't be liable for using data given to you by someone else, but what is your design basis if you don't?  Did you assume a value?  Should the worst happen, the initial lawsuit will not cherry pick designers, everyone will be named.  Do you want to be seen as a team player or the monkey wrench in the project?

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    Chad Morrison P.E., M.ASCE
    Professional Engineer
    Greenville RI
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  • 3.  RE: Geo and Structural Engineers - Collaboration Reality Check

    Posted 11-08-2018 07:56 PM
    Edited by Tirza Austin 11-08-2018 07:56 PM
    I submit to you that contractual constraints usually have a huge impact on the situation you describe.  Over the many years of my experience, I have found that the schedule and budget, whether an actual project or an RFP pursuit, largely dictates the level of interaction between geotechnical and structural engineers.  For example, if I am to provide building foundation loads, I need to assess what I can and will deliver based on how many hours are budgeted and how quickly I need to produce it.  I have seen where attempts at an ideal interaction usually requires a stretching of these constraints, including "gentlemen's agreements" to "work off the books", which is not a sustainable business practice.  The kind of situation you would like to see will require an industry wide change in the business model for engineering and construction.

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    Albert Ducker P.E., M.ASCE
    Sr Structural Engineer
    Gaithersburg MD
    (301) 258-8816
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  • 4.  RE: Geo and Structural Engineers - Collaboration Reality Check

    Posted 11-11-2018 10:59 PM
    Edited by Tirza Austin 11-11-2018 10:58 PM
    I am a structural engineer, but I started my career as a 'foundation engineer' and had the opportunity to see the exploration, design and construction sides of foundation problems. As such, I have been both a user and generator of geotechnical reports and have seen the collaboration go well or not exist.

    Contracts can be part of the problem. They can lead to poor lines of communication. However, that is mostly a matter of preparing better functioning contracts. There is also a misconception among a lot of engineers that if they have any interaction with adjoining disciplines then they are liable for all of the content of anything they look at. That's simply not the case and you will likely be sued regardless. It is necessary to have a clear allocation of scope and define that hand-offs as well as practicable. As always, your recommendations must meet the standard of care, even when coordinating with adjacent disciplines.

    I believe that one of the driving factors of poor collaboration is commoditization and how fee pressure that pushes firms to specialize in services that they can provide efficiently and profitably. Efficiency and profitability are enhanced  minimizing the amount of project-specific engineering effort in favor of standard details and templates; relying more on junior staff rather and less on experienced staff; and practicing defensively. As I understand it, for some base-building structural firms derivation of soil parameters, sophisticated foundation analysis and related construction engineering (excavation support, underpinning, etc.) is disruptive and potentially risky.  A lot of geotechnical firms make their money on drilling, laboratory testing construction observation. Project-specific geotechnical engineering and recommendations add costs and increase risk. Most building clients will not pay for this because they do not know the difference. 

    These fee pressures result in reduced scope for the geotechnical firm and usually a generic report with overly conservative recommendations and if any coordination with the anticipated construction or consultation after the report is submitted. In this the structural engineer is typically going to just take the excess and exacerbate it (I have more than once seen factors of safety doubled up on foundations and earth retention). Things can really go awry if the project changes and there is no budget to update geotechnical recommendations.

    However, it doesn't have to be that way.  I have seen sophisticated clients retain high-quality consultants in all disciplines and allow them to work together. When this happens the scopes are better coordinated and the design quality is higher. One of my biggest projects was a midrise building project in NYC where there was frequent communication between the structural and geotechnical/foundation firms (I worked for the latter). For example, of the excavation support had to be enveloped in the basement wall, requiring coordination of the soldier pile layout and penetrations for bracing with reinforcing and waterproofing. This sort of thing can be done if the scope and fee allow it. Granted, this project was before the real estate crash following the great recession. Commoditization seems to have worsened in all market segments since then. 

    Foundation problems are inherently site-specific and are more art than science, meaning that risk is inevitable and managing the risk requires experience. In the face of a low fee environment, neither structural nor geotechnical engineers have the incentive to approach foundation problems holistically; that is the root cause of the disconnect. You have to have someone at the table who understands the whole problem. That can mean retaining a geotechnical firm that still offers traditional foundation engineering services or a consultant like me. It helps if everyone is retained by the owner and to some extent directed through the architect or a program manager. Either way, the scope fee to allow the engineering effort and collaboration to take place. 



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    Richard J. Driscoll P.E., M.ASCE
    Lebanon NH
    rjd@...
    www.richardjdriscoll.com
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  • 5.  RE: Geo and Structural Engineers - Collaboration Reality Check

    Posted 11-16-2018 05:23 PM
    Edited by Tirza Austin 11-16-2018 05:23 PM
    ​Until a few years ago, I experienced what Stephanie described in terms of Geotechnical - Structural separation.

    The only link we, the Structural engineers, had with The Geotechnical engineers was to receive their Geotechnical report, and use it; often without even meeting its author.

    That changed as we faced greater challenges in deep underground structures where Soil-Structure integrated design becomes inevitable, especially with the new computing capabilities.

    The first such a challenge happened in 1996 when an existing LRT tunnel, built of slurry walls was to be verified for capacity under imbalanced lateral loads due to new construction. The structure had very little bending moment continuity between slabs and slurry walls (virtually pins). There was only continuity with the CIP middle wall that was too flimsy to offer sufficient continuity. There was no way lateral resistance to imbalanced loads can be achieved without calling on the lateral capacity of soil. That was heresy at the time. But under the pressure of necessity, the Geotechnical provided us with lateral Subgrade Reaction spring modulus. They were so reluctant to provide it to us, that they gave us the softest springs possible (as conservative as they could). Even with that, it made the design possible; yet with a lot of struggle:

    • Placed lateral springs in the computer model. Applied imbalanced LOAD COMBINATION (not load cases, since this will not be linear analysis)
    • After the first analysis run:
      • The springs with tensile forces were eliminated (since soil can't take tension).
      • Springs that generated reaction exceeding the passive pressure envelope, were softened by prorating the passive pressure allowed at that point/ the pressure resulting from analysis.
    • A second computer analysis run was done based on the above changes. Same steps were repeated: new tensile springs removed; those that exceed passive pressure envelope are softened by proration.
    • After several tedious cycles, the analysis converged to a stable result.

    Hallelujah, it worked; that existing structure was finally justified.

    A precedent was set.

    It came handy in 2012 when we were initiating 10 underground LRT stations to a country oversees. Those stations were deeper than usual, and the lateral imbalance was the governing factor. At the same time, their soil was exceptionally firm; offering great help if Soil-Structure integration was used. But there National Transit Authority of that country has never seen it before, and was reluctant to use it. However, with the help of our Geotechnical partner, a reputable European firm, we demonstrated that there will be major savings, running in hundreds of millions of dollars, if we tapped into the hidden capacity of soil. Our proposed method was approved, and it was incorporated in the design criteria of the transit authority of that country.

    In 2014, we used the above two precedents to introduce it to Canada's largest transit project of 15 underground stations. This time, with the help of more advanced computer programs that perform the above-mentioned iterations automatically. For that reason, the Geotechnical Engineer was a member of our Structural Focus Group. Perfect Geotechnical-Structural integration resulted in the greatest Value Engineering contribution to Canada's largest project. An added advantage, of thinning the external walls, was reducing the footprint of underground stations; therefore reducing interference with existing utility lines, a winning proposal.

    It has been a long journey, from no communication (pre 1996), to bare communication (1996), to cooperation (2012) to integration (2014-…). It's the way of the future. Don't be left behind in the dust.


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    Neil Kazen, M.Eng., M.Sc., P.Eng.
    FASCE, FCPCI, FEC,
    Retired Structural Engineering Manager, Transportation Division, SNC-Lavalin
    Toronto, Ontario, Canada
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  • 6.  RE: Geo and Structural Engineers - Collaboration Reality Check

    Posted 11-16-2018 05:24 PM
    Edited by Tirza Austin 11-16-2018 05:23 PM
    ​I think it comes down to being present when the project is scoped out, and lobbying for the involvement of a geotechnical engineer.  When the Owner and Architect are planning and developing the scope of the project, we need to get in front of them to explain why the geotechnical engineer needs to be part of the team through the duration of the project.  The person controlling the checkbook needs to understand that a good geotechnical investigation is an investment in the success of the project and the geotechnical engineer brings value to the team. If the geotechnical has the budget to stay engaged then collaboration with the structural engineer is more likely to happen.

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    William Black P.E., M.ASCE
    Senior Structural Engineer

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  • 7.  RE: Geo and Structural Engineers - Collaboration Reality Check

    Posted 11-18-2018 09:07 AM
    Edited by Tirza Austin 11-18-2018 09:07 AM

    Geo and Structural Engineers -  STRUCTURES are load-bearing substance and are supported firmly on the ground to remain in static position of rest.

    The design configuration, classify structure into two category, ie, The Super Structure, for the parts above the ground, and Sub-Structure/Foundation, for parts within the ground soil.

    Geotechnical Engineers are specialist in the soil, and do evaluate the basic parameter necessary for load bearing and support support consideration. This information is used in determining the extent of load application unto the soil by the structural engineer. The design of the super structure is guided by the architect information and structural design standards and codes.

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    Olusegun Afolabi P.E., M.ASCE
    University of Lagos
    Lagos
    234803 4248600
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