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  1. tq3610

    Battered Pile in Compressible Soil

    I haven’t yet analyzed it, but I am aware that FHWA says not to use battered piles in compressible soils due to the bending that would result to the piles from settlement. So, I’m looking for some input as to how I can account for the load from settling soil on the battered pile (ie, apply an...
  2. tq3610

    Battered Pile in Compressible Soil

    For a site with compressible soils, a bridge abutment has lateral loads to be resisted by piles. FHWA states to avoid battered piles in this instance. If they can't be avoided (i.e., soils are too weak to get significant lateral capacity from vertical piles), does anyone have a reference as to...
  3. tq3610

    Pile Lateral Load

    Thanks Retro. I was looking at h pile/micropile but I’ll note this for future reference.
  4. tq3610

    Pile Lateral Load

    Thanks Steve - that makes sense.
  5. tq3610

    Pile Lateral Load

    Possibly another interpretation considering AASHTO LRFD 7: C10.7.3.12: The strength limit state for lateral resistance is only structural...this limit state is reached...when the nominal combined bending an axial resistance is reached." For serviceability the code essentially leaves the design...
  6. tq3610

    Pile Lateral Load

    Per IBC: "Where required by the design, the lateral load capacity of a single deep foundation element or a group thereof shall be determined by an approved method of analysis or by lateral load tests to not less than twice the proposed design working load. The resulting allowable load shall not...
  7. tq3610

    Pile Lateral Load

    A question on the evaluation of pile capacity. In general, the pile size is calculated based on the vertical load capacity required. Then often an available lateral load on that pile is calculated and provided for design. For a vertical pile, when checking the available capacity of the pile...
  8. tq3610

    Liquefaction

    In the past when I've had potentially liquefiable soils I've evaluated liquefaction potential using the CRR:CSR method, which includes a magnitude scaling factor for the magnitude of earthquake in question. I'd refer to the USGS earthquake probability mapping program that mapped probability of...
  9. tq3610

    Strength of Soil for Rapid Drawdown

    I've considered the material to be just a bit below the USACE recommended permeability to be free draining. So I'm assuming the material will need to consider the undrained conditions. Per FERC, the lesser FS using drained and undrained strengths were considered. NAVFAC DM7.02 assigns an SM...
  10. tq3610

    Strength of Soil for Rapid Drawdown

    I have a small dam to be analyzed for rapid drawdown. No specific laboratory soil strength data available, but I have boring logs and gradations. The average N60 value through the embankment soils is 23 bpf. Gradation tests on the embankment soils show the material to be sand with ~10% gravel...
  11. tq3610

    Blast Vibrations

    Thanks Eire - You are correct - both seismic and blast were considered separately. The earthquake event I would consider to be much different than the blast event (duration of vibration 10s versus blast 1s, and frequency of occurrence 500 yrs versus many times per year). So, my consideration...
  12. tq3610

    Blast Vibrations

    Thank you GeoEnv - your comment is understood. Your point is taken and I had already considered this - if 1m of displacement is too much, then what is the point of taking that approach... That said, I can also perform a Newmark analysis to evaluate slope displacements. The input of the time...
  13. tq3610

    Blast Vibrations

    Will do - deleted from the other. My apologies.
  14. tq3610

    Blast Vibrations

    In modeling seismic slope stability, it is "typical" to model the horizontal acceleration coefficient of 0.5xPGA(site modified). It is my understanding that the 0.5 factor applied to PGA is to account for short duration of loading. My question is, if a site has site-specific ground vibration...
  15. tq3610

    Dynamic Load Testing of Pile on Hard Granite

    Thanks MTN. I agree the building inspector isn’t going to approve a foundation based on gut. I’m more just asking if there is a fatal flaw in the premise that the additional load from 1000T to 1200T in this scenario is essentially inconsequential as far as whether it puts the foundation system...
  16. tq3610

    Dynamic Load Testing of Pile on Hard Granite

    The basis of this question isn’t in an active project where I’m trying to increase a pile capacity. It was a years old project where the calculated static capacity was 1200, but the foundation contractor’s engineer said the pile could only achieve 1000 based on their WEAP analysis and their...
  17. tq3610

    Dynamic Load Testing of Pile on Hard Granite

    The pile is driven to 45ksi during driving. At 45ksi (driving stress) the calculated ultimate capacity per CAPWAP is 1,000T. That driven capacity is not equal to the allowable load given by static analysis of the pile section. This is due to the particular hammer, soil conditions during driving...
  18. tq3610

    Dynamic Load Testing of Pile on Hard Granite

    The reason for the 1,000T versus 1,200T is based on the driving stresses in the pile. Hitting the hard rock, as you stated, results in a quick increase in pile stress. It may only take an increase of 1 blow to go from 900T to 1,000T to 1,100T to 1,200T. 1,000T results in a stress of 45ksi...
  19. tq3610

    Dynamic Load Testing of Pile on Hard Granite

    I'm looking for some input on dynamic load testing of an end-bearing steel pile in hard granite bedrock. Consider a PDA test was carried out on a steel pile acting in end-bearing (~90% EB, loose granular soil above rock) that results in 1,000 tons ultimate capacity at a given set blow-count...
  20. tq3610

    Pile Driveability

    Thanks. I decided to just go with grlweap2010.

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