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  1. JSD1986

    Deep Excavation - AMA

    1) Using 2d analysis software such as plaxis/wallap we obtain the 'strut load per mtr'. 2) Guess the capping beam and strut sizes and geometric arrangement. 3) Analyse the system using software like strand7/spacegass. use the forces obtained to design the reinforcement of the beam. We have to...
  2. JSD1986

    Deep Excavation - AMA

    Im not sure what country you're based in but in Australia there is a technical specification which covers this exact type of situation. Standards Australia SA TS 101:2015 - Design of post-installed and cast in fastenings for use in concrete. I'm not suggesting there aren't potential design...
  3. JSD1986

    Deep Excavation - AMA

    N16 at 300 cntrs good for about 110kn/m ULT in pure shear which ignores the fact its notched to some degree into the shotcrete wall. Column row typically about 8m off the shoring wall. Say 20kpa ultimate UDL with 4m load wide = 80kn/m shear load at the pile interface. On first glance this...
  4. JSD1986

    Guess the settlement - Dynamic Load Test

    agree. you have to be 100 confident that who ever is reading your stuff if on the same page. Care to hazard a guess at the load displacement?
  5. JSD1986

    Guess the settlement - Dynamic Load Test

    Interesting. The piles will be installed this week. Just so im clear - each T is 2000 pounds right? Im in SI world..... Any more guesses?
  6. JSD1986

    Deep Excavation - AMA

    The capping beam is poured with the shear plate in place so i'm fairly confident there is a fair amount of load being taken up via skin friction between the plate and the RC beam. The strut is designed for this sag. Without considering these second order effects the 710 CHS is good for about...
  7. JSD1986

    Deep Excavation - AMA

    When I workout the shear load being transferred into the capping beam I need to be able to justify that not all the load goes through the shear studs - that some occurs with friction between the plate and the concrete. Adding some hard faced beads gives me a little more confidence that this will...
  8. JSD1986

    Guess the settlement - Dynamic Load Test

    Who wants to play a game. In two days I am installing two 750mm dia CFA piles. One pile will go 21m and the other will go 26m. A week after these piles are installed we will be using a 16T lead drop hammer and carry out PDA/Capwap analysis. The piles are not contract piles and we will...
  9. JSD1986

    Deep Excavation - AMA

    PEinc - The deep wells are designed in such a way that the 'draw down curve' is below the excavation and removes hydrostatic pressure from the wall. There were also spears installed from the lower level as the wells didn't quite do the job. killswitchengage - The slab dowels into the piles...
  10. JSD1986

    Deep Excavation - AMA

    PEinc - The pile installation was underway when the client advised that a hydraulic tank in the corner was required. This made the excavation approx 1.5m deeper which made the pile reo and length insufficient. This extra brace was installed to solve this problem. killswitchengage - they are...
  11. JSD1986

    Deep Excavation - AMA

    Deep Excavation - 13m cut. Approx 8m below water table. Any quesrions.
  12. JSD1986

    plaxis 2d vs wallap

    Forgot about this thread. The answer was - strut EI was a factor of 100 too high which threw more load in that direction.
  13. JSD1986

    plaxis 2d vs wallap

    Thanks for the input, its more like Soil: g=20kN/m3; f'=37º, delta=19º - Surcharge: 15kPa - 4m of hydrostatic. We build the shoring systems to, so in reality im going to go a mid value range and put some strain gauges on the struts and have a contingency to add a second row of bracing. The...
  14. JSD1986

    plaxis 2d vs wallap

    I use wallap and plaxis essentially all day at work. I often compare the two for shoring wall designs. Typically I find the two are in general agreement ie similar bending, shear, deflections. In my experience plaxis shows higher strut loads - maybe 10-15% more. I have just run a model and the...
  15. JSD1986

    Shoring Wall - Corner Brace Thrust Capacity

    SlideRuleEra - the above was just a random depiction - however by raising the brace level the brace load would be less but I believe creates more issue as the distance between the centroid of the shear resistance to the strut load increases and induces overturning to the whole system.
  16. JSD1986

    Shoring Wall - Corner Brace Thrust Capacity

    SlideRuleEra -typical weld is 150mm weld top and bottom of waler to each sheet at 750ctrs, weld is 6mm continuous fillet weld. so each sheet pile is very well connected to the waler. PEinc - yes found that doc - was a good read. ~15m cut depth failure is the stuff I have nightmares about. If...
  17. JSD1986

    Shoring Wall - Corner Brace Thrust Capacity

    Geopavetraffic - yes when the wall is fully enclosed 'box' then yes not really an issue. I have looked at it the same way as you by working out the kpa required and using judgement to decide if the kpa is reasonable. - however still cannot find any literature on this. SlideRuleEra - walers...
  18. JSD1986

    earth retention_tiebacks vs struting

    Rapt- im with you, we call it naturally de-stressing of anchors once excavation above anchors occur. essentially zero risk leaving stressed anchors in the ground. Once the earth above them shifts a bit the tension is peacefully released.
  19. JSD1986

    Shoring Wall - Corner Brace Thrust Capacity

    Hi everyone, At the company I work for (design and construct shoring wall contractor) it is common to implement a corner brace for , say, a sheet pile wall. Analyzing the system in 2d is simple: prop forces, embedment, wall forces etc. However I cannot find any guidance on how to resolve the...
  20. JSD1986

    Pile Cap - rationalising force path to neglect lateral load in tension piles.

    I know for a fact that this type of rationalization occurs in practice and as a reasonably inexperienced engineer about to get my CPENG I'd love to know if there are any legs to stand on should this need to be officially debated.
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