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  1. hughits

    Minimum height of grade ring required for concrete manhole

    @ cvg, our standard shows 150mm minimum and 350mm maximum. Again, I am not familiar with grading/earthwork stuff, but I guess it depends on who designs, how much room you have for adjustment in the future and such. I didn't know that bricks can substitute concrete grade ring. Thanks for the...
  2. hughits

    Minimum height of grade ring required for concrete manhole

    I checked with our civil designer regarding this matter. As CarlB said, I guess any potential change in the grade elevation in the future is unlikely. He advised me to accept as is. Sounds like 150mm is typical, but the rule could be bent depending on the situation. Thanks guys for your opinions!
  3. hughits

    Minimum height of grade ring required for concrete manhole

    The minimum height of concrete grade ring for manholes/sanitary manholes is specified as 150mm on IFC dwgs for a project I am working on. I got a phone call from Conctractor saying that this minimum height requirement could not be met because the elevation of some manholes installed was higher...
  4. hughits

    Steel pipe piles hitting an early refusal. Any recommendations?

    For specifically the pile in quesiton, I wouldn't worry about it too much at this point. The design loads for tension and compression are 960 kN and 1170 kN, respectively. The capacities we obtained from the PDA test are 4100 kN and 5200 kN for tension and compression, respectively. I didn't...
  5. hughits

    Steel pipe piles hitting an early refusal. Any recommendations?

    Mostly sandy soil with a little bit of silt and clay here and there. Checked the soil plug elevations, but their pattern doesn't seem to be correlated with the driviability. The required tension capacities vary between 500 and 1500 kN. We decided to do PDA on those piles hitting early refusal...
  6. hughits

    Steel pipe piles hitting an early refusal. Any recommendations?

    I got your point. I understand that it's similar to deep-seated failure of a retaining wall conceptwise. I will have to have the geotechnical consultant check this failure cone, too. Thanks again for your valuable opinions.
  7. hughits

    Steel pipe piles hitting an early refusal. Any recommendations?

    Thanks for your answer! Actually I made a decision to do PDA on all of the piles in question. I didn't want to do anything further without knowing what capacities I need to get and I have currently. Then I will go from there. Thanks for your opinion that supports my decision. This is good!
  8. hughits

    Steel pipe piles hitting an early refusal. Any recommendations?

    That's true. Nobody knows what's in there and what's preventing us from reaching the design depth, which is the reason why I am seeking for solutions for this issue. Currently what we rely on are two things; more than 100 blow counts/25 cm at the refusals (we concluded that any further attempt...
  9. hughits

    Steel pipe piles hitting an early refusal. Any recommendations?

    Thank both of you! I am using open steel pipe piles, so I don't have to blow the end as Ron suggested. Micropile idea sounds good to me. I am not sure if the pile tips are crushed or not. The pile diameter is 508 mm, which I think large enough. Thanks again!
  10. hughits

    Steel pipe piles hitting an early refusal. Any recommendations?

    Ron, thank you again for your input. Yeah, that was my mistake. So basically what I will get from the Augercast piles is additional frictional resistance in either tension or compression due to the fact that the piles densify the soil around the main pile. Hope this is correct.
  11. hughits

    Steel pipe piles hitting an early refusal. Any recommendations?

    Thanks for your valuable recommendations! Well, if the pattern of the probable hard lense was predictable, I would pre-drill down to wherever I am comfortable with, but it is not. Hence, the second option sounds better. One question in this option would be once Augercast piles are driven around...
  12. hughits

    Steel pipe piles hitting an early refusal. Any recommendations?

    I am a structural engineer working on driving steel pipe piles for an oil sands treatment facilities. Based on the soils report and design drawings, the design embedment of most of the piles range from 20 m to 26 m. The pile top cut-off elev. is about 1.5 m above the final grade, so the total...
  13. hughits

    3D Foundation

    I used Plaxis to model MSE wall for my MS, but it was 2D. Looks like no one has tried it? Sorry not to be able to help...
  14. hughits

    Compressor foundation on weak rock?

    Hi, I have been googling here and there to find some answers for my questions, but no luck. I am designing a block foundation supporting a compressor skid. Design itself is okay, but I have a little concern about the contact between the foundation and soil. The surface soil at the job site is...
  15. hughits

    Foundation subgrade modulus

    Most of the typical values found in many references are normally given in ranges simplely because they are typical values in my opinion. What valve you want use within the range is solely up to you (of course if you want to use the typical values). I would use a value that will give me a bit...
  16. hughits

    Pavement settlement on top of MSE wall and wall settlement

    I'm doing my research on MSE wall (Highway project) for Masters degree. My questions are as follows: Is there any criteria about the tolerance of pavement settlement paved on top of MSE wall? Is there any criteria about the tolerance of settlment of foundation soil under MSE wall? I read...

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