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Mini Ex sheet piling or shoring

Discussion in 'Compact Equipment Attachments' started by andrewpond, Feb 12, 2020 at 2:41 PM.

  1. andrewpond

    andrewpond Well-Known Member

    Sep 30, 2012
    HI , Have a site that has long history of site contamination.... I am removing 5 old style car hoist (1 large cylinder in center) in a large auto service garage ie 12 hoists. The issue, is even before it was installed there was environmental issues on site. The excavation is: 8" thick concrete floor, 30" "A" gravel, (here is issue) 6 feet of 3/4 Clear stone and 36" steel corrugated culvert on vertical with the hoist cylinder inside unknown back fill.... likely some concrete but could be 3/4 stone....

    Total depth is approx 8 to 10 feet.

    1 hoist is started
    there is 8 ft sq hole for each hoist cut in floor. We can see undermining back 4ft at 4 ft depth ie 45 deg....

    Looking for solution to retain 3/4 so we don't under mind floor....

    Sheet piling w Mini Ex ? I don't think trench box will work as 3/4 will move before the trench box drops??

    Site is in auto garage with 14 ft high ceiling and its only $3k job so I cannot get too crazy w $$

    Last edited: Feb 12, 2020 at 3:04 PM
  2. Tugger2

    Tugger2 Senior Member

    Mar 22, 2018
    British Columbia
    What is your scope of work ,to remove the parts of the hoist only or to remove both the hoists and the contaminated soil as well?Has the site been tested,if so what are the contaminates. If your planning to dig a hole deeper than 4' it will need to be shored or sloped 1:1.Is there ground water to deal with?The magnitude of the shoring will be dictated by the depth of the hole,if you are going down 8' that will require substantial shoring.This will require an engineers input to begin with . 14' ceilings would probably make this a low headroom sheet pile job, meaning your going to drive short sections and splice them as you go down and cut them apart as you extract them. If the contamination was serious enough to require full remediation it you would probably have to demo the building to do the ground work. If im clear that your budget for this work is 3000.00 i would remove the hoist components or cut them off below floor level and restore the floor if this is possible. Leave the excavation alone even though the digging itself seems simple the bureaucracy is overwhelming ,3 k wont even get the consultants to the site to begin with.
    Ronsii, CM1995 and Mother Deuce like this.
  3. redneckracin

    redneckracin Senior Member

    May 20, 2010
    Civil Engineer
    Trench box it or demo the building. You could use the hoe to help push down the box. If you are already undermining the slab you have some bigger problems. The remediation sounds like the larger issue here. How are you going to know when you are meeting your cleanup requirements? I assume you have a P.I.D. meter and lined rolloffs boxes with a proper clearance for disposal?
  4. bobcat1

    bobcat1 Well-Known Member

    Nov 13, 2014
    Does the three foot corrugated pipe have to come out or can it stay in place?
  5. KSSS

    KSSS Senior Member

    Feb 27, 2005
    I think there a couple ways to do it, but 3K is not enough money in my mind.
    Ronsii, hvy 1ton and CM1995 like this.
  6. CM1995

    CM1995 Super Moderator

    Jan 21, 2007
    Running what I brung and taking what I win
    I agree.

    $3K is not even enough to cut 5 hoists 1' below grade and pour back the floor, leaving everything else in the ground.
    redneckracin, Ronsii and hvy 1ton like this.
  7. crane operator

    crane operator Senior Member

    Mar 27, 2009
    sw missouri
    Yeah, but he's in Canada, so if it 3k in canadian loonie's, he's working with even less $$$ than you guys are thinking. $2,260 in USD right now.

    I think if everything has to come all the way out, you've got issues.

    I think I might try to just make a hole in the concrete just big enough for the top of the cylinder (3'x3'), weld a bar across the top and a 20 ton bottle jack on each side and jack the cylinder loose. Then pull it out the rest of the way with forklift. Backfill the "cylinder" hole with clean, then remove your 8' x8' concrete and repour.

    Depending how the hoists are made, some are really difficult to cut off 1' down. None of this works if the culvert has to come out and all the "contaminated" soil.
    Ronsii likes this.
  8. Ronsii

    Ronsii Senior Member

    Jun 26, 2011
    s/e Heavy equipment operator
    Western Washington
    LOL!!!, I was just thinking along similar lines to 'crane' them out :) cause anytime you got 'contaminated' around here it gets ridiculously expensive/time consuming/paperwork hassles!!! and the second you 'touch' some dirt that test positive... it can NOT!!!! go back into the ground!!!! PERIOD!!! even though it had been in the ground for 50 years or more before that... :rolleyes: so then you need suitable fill... which usually means suitable structural fill..... properly compacted and probably tested with a nuke or something... so now you gotta have an abatement guy on site and a soils guy there to make sure you fill it properly... I doubt 30K would be enough for a job like that.... the last job we were on that had 'dirty' dirt... ;) we had to chase it down 10 more feet and three truck loads :eek:
  9. Bls repair

    Bls repair Senior Member

    Jan 21, 2017
    Equipment operator,mechanic
    S E Pa
    I would walk out front door and keep on walking and not look back:eek:
    Tugger2 and CM1995 like this.