Existing 5000 sf warehouse floor to be removed and replaced. Floor is concrete over wood. Wood framing similar in concept to a raised floor house with 2x joists, cripple walls in most of it, although wood girders in one section. Has perimeter concrete foundation and interior grade beams; both short stem wall shape. Due to vintage, flooring sheathing is two layers of 1x. No plywood. A wire mesh reinforced concrete was placed directly on the wood. We figure concrete to be about 50 yrs ago, give or take. Wood is dry rotted and many repairs conducted over the years. This 'repair' is to remove everything and fill, then place a new concrete floor. Initial actions were to brace the roof and walls in sequence and replace the oortion of the perimeter walls to the floor elevation with either grouted CMU or cast in place concrete. Then cut through the dock to gain access to the inside and remove the old materials. Trials were conducted on the concrete removal process: sawing it to make squares and pulling it up with a quick bolt/chain/etc accomplishes the separation although the sheathing sticks to the concrete. Sending the concrete to the recycle with this amount of wood is a no no, so the decision to cobble the concrete squares by working the hammer atop the existing slab achieves quite a bit of separation, and the cobbles sent to the bottom of the approximate 5 foot fill for "permanent storage". The wood removal goes equally slow as it is so rotted it falls apart mostly but occasionally there are members which require sawzall etc. Walking on the sheathing after a square cube of concrete is removed will get you a leg down and maybe a rusty nail bite LOL. The wood gets smashed up and dismantled with the reachlift, then hauled out with the forklifts and bins to go into the rolloff containers. Some of the above is shown in pics. Seems the overall process has become concrete removal & cobble, then the wood removed to make a hole to place the concrete. Process is sort of iterative in lieu of sequenced. One bay is almost done in the pics. For those of you who work in soil with cobbles, maybe a comment please. I could speed up the process by concentrating efforts on removing all the concrete, rubble it, then place & mix it in lifts in the one section that is completed that you see in the pics (dump truck hauls the fill inside and the skip spreads it, reachlift and skip wheel roll is compaction on this lift and the sheepsfoot ride on compactor will be next (just to make sure and get the edges better) prior to any more fill (am about 15" filled of rubble and soil, just enough to cover the interior grade beams & rubble so we could drive the reachlift and dumptruck). The fill is inert (minimal clay) sandy loam, mostly sand. Fill is pre-conditioned with moisture prior to hauling it into the building. My Question: Unsuredness is holding me from bringing the concrete rubble 'too high in the fill' - but if I could mix all the concrete in this one bay/section, then I could attack the balance of the wood all at once with a midi ex and a thumb then hire a crew for a couple days to load the roll offs with that wood. Then I could 'get after it' for the balance of the fill and the new 6" slab. Any suggestions on getting good compactible subgrade with these cobbles? Size ranges from less than a square foot to a few at 18 by 12 by 4 thick with one or two at 18 by 18 by 4 thick. Would you fear having a compaction job with mixed materials? I would hazard a guess and say it will take about 3 feet of mixed fill (ie sand w cobbles) depending on the ratio to get a home for the concrete in this first bay. That would give me 18" of sandy material with no cobbles and 6" or so of Cl II base under the slab. Never worked much with mixed fill as am usually in pure sandbox style soil where we remove, moisture condition, and replace. Regarding how to deal with cobbles - does 'engineering opinion' allow these cobbles "back in the ditch/fill" or are they always to be screened away? We simply can not take this concrete to the recycle since there is just enough wood stuck to it to make it rejectable but not enough wood to allow it for fill due to organic less then 2%. There are no pipes or conduits, only the fill with the concrete atop.
Bob you've got an interesting project to say the least. I haven't run across something constructed in that manner, it's a wonder it held up so long with warehouse traffic. We encounter rock fills on our jobs from time to time. One was a 20' deep fill with shot rock. The artic trucks dumped at the proceeding fill lift and we pushed it off with a D6. The larger pieces went to the face and the fines covered the preceding lift. This fills the voids around the larger pieces of rock and levels out the lift. You'll need to do something similar but a different approach. So you will have 2' of engineered cover with 18" of sand and 6" of base? The key to reduce settling around the concrete fill, especially the large concrete pieces, is to lay the largest pieces out flat on the very bottom of the lift. Leave adequate space around the pieces to fill in with your sandy material. You may have to lay the large pieces out, fill in the voids around them with sand and then a layer of smaller broken concrete. What you don't want is the large pieces piled in one spot on top of each other in a manner that creates voids, over time the sand fill will work it's way into these voids and cause settlement. 18" of cover to sub-base is the minimum I would go over the concrete fill. I'd pay special attention to the first lift of sand over the concrete and make sure the sand is vibrated throughly in order to fill in all voids.
Appreciate the suggestions. If you look at the pic with old wood coming up, "peek" beyond the wood, there is a temporary rubble pile that 'had to go somewhere'. That wood in that pic is now gone and I will spread that rubble out with the mini before the next lift ... I knew that type of rubble pile covered with sand fill wouldn't be good at all. Gives an idea of the size of the pieces.
That's a interesting project for sure! I see you've got a skid bucket chained to the folks on your tele, did the same thing a few days ago to backfill around a pool. I would think so long as the concrete is in small enough pieces that the sand can flow around it should be fine to bury it.
Since you mentioned the [two] chains on the accessory bucket for the reachfork..... that bucket has these two pockets for the forks to slide into and on the heel are these ears with a hole; a pin traps the fork into the bucket : NOT! The bucket is so loose on the pockets that the fork becomes dislodged from the bucket (jumps over the pin) and so to add assurance it won't fall off the machine we dreamed up those chains with some shackles (to R/R) around the carriage bar. Aside from that, this bucket comes in quite handy. I initially thought I wanted a wider one, but that makes the overall turning clearance bigger and the reachlift is already long. Bucket setup is not suggested for excavating but it handles loose materials well. * * Thanks for the comments on the fill with and over the concrete chunks-cobbles. One person (my helper) suggested: ```after we place a lift 12 to 15" of combined fill material (ie cobbles with sand placed over and coincidentally wheel rolled due to direction/method of placement) then ```use the excavator bucket to loosen or till/agitate the material [I imagine many short strokes similar to tilling up a garden - not long plowing action but it prolly is the same effect] ```put a little more water to it, ```then compact that lift with the ride on vibrating sheepsfoot. I asked him why he thought that was better and he said he didn't really know but that is what idea came into his mind. He is a good compactor operator, always achieves good numbers, drives the machine calmly, etc. As to placing the unbroken square sections (like pieces of a sidewalk) shaped concrete: 1) I feel that random chunks (because they are simply smaller is a bit better) and the time to break up those sawn sections into cobbles/rubble is pretty quick. 2) And I would offer that handling the concrete material will take less time by first processing it (busting it a bit) and filling many chunks it into a bucket to spread around as opposed to setting one squarish slab at a time like a checkerboard - as that could also be a pita. LOL Pita means 'Patience Is The Answer' as in a trial of one's patience, not the colloquial acronym.
Some more pics showing one bay filled with a layer of cobbles and the fill just above those rows of foundation grade beams, and half the center bay similarly to the above mentioned bay but with another layer of spaced cobbles ready to receive their layer of fill/cover. The cobbles are spread carefully with a machine and moved &/or located by hand to assure there are "no stacks". Then the pre-moistened soil is thinly added to just cover the cobbles with a couple inches and then some more water added* then credit taken for the loader wheel roll, then the compactor and it in two directions if possible. The time to further break into cobbles the saw cut out slab pieces isn't much and it seems better to accomplish this project using only cobbles as opposed to those larger saw cut pieces: also they are slow to handle for the placement. *Sandy soils tolerate the over water as opposed to the clay soils so this factor was added into the recipe, figured the wetter sand would move or mold around the cobbles more readily. We are looking ahead to locate a Z boom concrete pump as it may be able to open/unfold inside the room. The larger boom pump beats dragging a co concrete hose and allows for a mix design with more 3/4" aggregate. Larger aggregate helps with the shrinkage cracks. Sadly, concrete in fact cracks but we keep it to a minimum by using certain types of dowels that allow horizontal movement but not vertical, and a rebar mat centered in the slab.
Hard to tell about access (I see some columns to work around) but a concrete conveyor might be able to boom into there. I understand they have no restrictions on aggregate size. Unique project for certain. Remember there is profit in unique. Just an idea...
We have heard the use of a telebelt (which is what they call a truck mounted conveyor belt(s) that has a frame that can extend retract) will be worthy of investigation. * As to unique, fyi the building was originally carpentered in 1940, possibly 1937. Likely some of this portion was one of the additions - let's say 1945. All 2" thick wood: 12" section on floor and 8" on walls; tongue and groove both sides of the walls....etc etc. Built with no electric saws, no skilsaws, no sawzalls, no drills, no impact guns, no manlifts, no forklifts...just handsaws & hammers and a nail pouch. No wonder my grandfather [a carpenter and a brick mason] gave me advice on not to take a career or job in construction. Am glad to be the one to give this old structure a new floor.
Looking good Bob. I don't think there will be an issue with settlement of the new floor. No doubt on the old school carpenters. My grandfather and father were both carpenters back when a skill saw was a revolutionary tool.
We made it to the end of the removal of the floor. There's a couple details for some hammer work, but the wood is all but gone. Using the reachlift has helped spread just an appropriate enough fill material (sandy soil) to cover the cobbles and it gets really wetted to 'flood it in' then track roll and kneed w bucket to help assure no voids. The layer of cobbles and followed by the skip loader was placing a bit too much cover. Still researching how to get the boom pump thru that door.... Now a few more cobbles to place and then "fill baby, fill".
https://www.youtube.com/watch?v=ZS8-kHViiy8 A semi local basement company has one similar to this.
Getting it filled in. Subgrade work. Then a layer of class II base under the concrete slab. As to the concrete and the placing method, there are three bays and we knew we wouldn't do it all at once and thought maybe one then the other two but have decided to do the initial bay against the wall by "hose dragging" as there is no exterior door in line, it is also the shortest bay. We are going to get that one in first.
Project is coming along nicely Bob.
Pic of our 1000#, single cylinder, diesel of course!, Hand Crank Start plate compactor finishing off the marks from the padfoot and smoothing the top of the subgrade prior to the road base. The guy who sold me this didn't put a throttle cable up to the handle as he used a small vise grip to hold the throttle lever in the run position. One fine time, he started it and it lit off quick so quick that he didn't pull the crank start handle so the thing was spinning wildly off the racing engine and the compactor was jumping/dancing all over ... it was full of fuel and he couldn't wait till it ran out so he carefully? reached over & around the spinning crank, released the vise grip but they sprang from his clutches and fell just in time for the handle to come around and launch the pliers onto the side of his face / cheek. It looked like he walked into a pipe or similar type of injury. Yes we have a remote throttle via cable. And it is a Beast to drive around but I like it cause it is diesel and it hits the ground brutally.
Got the base to grade and some forms. Still a ways to go on the fill on the final portion.
Would a tele-belt truck work? That's a cool little single drum. How wide is it?
The other day we had the one section up to final grade and road based, and yesterday's long day we succeeded in mortally wounding the premoistened soil in the stockpile. Took some pics last nite of the final section almost filled 'cept for the haul ramp and the dock. Single drum compactor has a Deutz air cooled, mfg by Dynapac, is a CA12PD (not a current model) with a drum of about 4' in width. Also some fyi concrete slab details: notice no rebar laps 'inadvertently' in the saw cut (crack control) joints nor any bars skewing aiong said cut line(s). also notice on the construction joint (ie 2x6 form board facing the next slab) there are the diamond dowel pocket formers where a plate dowel will be inserted once the form is removed. Dowels to the perimeter wall are smooth & square section. Slab is a full 6" thick. Stakes in center are the clips we set for the skreed rails and skreed rods. This concrete will be placed, potato head vibrated, hand rodded in lieu of vibrating skreed just because the issues with the pipe rails for the vibrator with all the columns & walls. IMO Never achieved decent flatness with a "wet screed" vibrating skreed, we always run it on pipes; the slump will be kept to a 4" which the vibrating wet screed is also another challenge for it. Finish will be channel floated and panned, and walkbehind trowelled (no rider which really helps w flatness but is a bit of a chore to handle). Mix design is .53 w/c ratio with 5 3/4 sacks cementitious [which is the word used to address Summation Of Portland Cement and Flyash content], fyi this has around 10% flyash. The aggregate is a blend mix adjusted to trailer pumping via a 3" hose. and mix water is certainly being replaced with medium and high range water reducers, also there is no air entrainer. Regional geographic aggregate is a fairly significant contribution to concrete shrinkage compared to data we have seen in other parts of US thusly rebar for temperature and shrinkage as well as seismic considerations. Likely will be accelerators* (and/or additional cement content) due to the inside placing conditions where it is cooler not to mention we are coastal weather which some days can be get as high as 68 to 72 F. *Want to allow slab for forklift operation at 3000 psi w/i a week or so of placing. Owner suggested we should consider fibers too....maybe we will, but they increase water demand.
oceanobob, good work! A long time ago, I worked on a job like that one. The engineers designed an under slab fill using rigid foam; geo foam. Truckloads of 2' x 4' x 10' foam slabs. It was really easy to put in place. They pored the concrete slab warehouse floor on top of styrofoam! (The concrete contractor used a laser screed and no forms or screed boards, it was very quick, and it came out very flat!)
We have no laser skreed operations in our area. We cajole them to travel here when the jobs are at least 10 to 15k SF. The one bay that had to be done with a hose pump (no hope of a boom or other contrivance due to no door access) was completed yesterday. We selected a mix that had almost 1800# of rock (not counting sand) and kept the cement to 5.5 and lessened the water with chemicals, also added a small dose of accelerator. The hose made the job slow, that was apparent right away so we 'stepped out of the line at the batch plant' on the final truck. Because we went early, there wasn't a major consequence with that last minute adjustment. The last truckload we added some more cement and some big fibers and a little more accelerator as that truckload is a pathway to another part of the warehouse (help occupants gain access asap). The slab was vibrated, handrodded with aluminum skreed rods, carefully floated and holes filled, then observed: there was little bleedwater so we knew we had reduced quite a bit of the water; film was added to protect the surface although our humidity was around 60% and no direct sun. Panning and channel floated reiterations once it could be walked on, then machine finished and film curing compound applied. 9 hours and the rest of the cure application had to wait until we could walk on it w/o boot marks at hour 11. Clearly the room low temps don't help setting. At the construction (cold) joint, edging was not performed as this usually 'rolls the flatness away', instead the plan is for the next bay gets bumped against this one and the butt joint gets a saw pass to clean up the appearance and the sealant/low modulus epoxy added. For the equipment folks: I have worked with this 'one man and a helper' concrete pumper, he maintains his equipment and it is reliable. His hourly rate is 'above market'. Not knowing too much about the pump mechanism, but over the years we have endured clogs and stoppages with other companies so I stay with this outfit. The finishers don't pay this rate and they don't typically push the rock content since all concrete is the same ? When they learned the rate, they were cantankerous (pls recall I was paying it) so I asked them "Do you like Clogs/Stoppages/Beating Hose with mallets etc etc." They quieted up, but value is a difficult concept sometimes.
Compactor makes final exodus and wet saw cutting crack control joints.
Good job Bob. I've enjoyed reading the updates on this project. Those orange plastic "dowels", tell us more about those. I have never seen them. I have a one man line concrete pumping outfit we've used in the past. Like yours, he's not the cheapest but when you need a line pump he's the one I call. I prefer owner operators than using larger outfits.
When doing construction joints, the load transfer across the joint has been a topical evolution involving such things as smooth dowels, key forms, or rebar (&/or combinations). Sometimes the form is drilled for rebar but the form becomes quite obstinate to remove from the hardened concrete. One slab, being ahead by virtue of schedule, is also shrinking and moving accordingly so I elected to try the diamond dowel system made by pna. Another variant is to remove the form then drill and epoxy a smooth round dowel, or one could install a sleeve form for a round dowel is also available. In summary, there are a few options. I figured the notable surface area of the plate would provide significant load capability and readily allow shrinkage in two directions in the given plane. We painted the plate with SW's Macropoxy epoxy to provide corrosion protection. The pics show skim cutting the cream (1/8" or less) from the form at the inside face plane (although many insist necessary to keep the form top perfectly clean), a grinder cut off wheel to remove the nails, and the dowels installed in the pocket form. The level is shown as a straight edge to show the care to keep the surface flat in the vicinity of the slab edge (ie no edger tool allowed).
And two more pics to follow the above...
Thanks for taking the time to explain and take pics of the system Bob. How does it compare in cost to smooth dowels?
We got the diamonds (pocket and plate) for about $3.00 each and effectively almost $1 ea for the UPS across the state. A twenty foot square dowel uncut of HR is delivered to our job at around $.50 per foot and the square dowel uncut of CR is $1.50 per foot; I would surmise this is a similar budget for a round bar. Pls note, the performance of a plain dowel (drilled/glued/balance greased) isn't considered similar to the square or round dowel with a "sleeve contrivance" that allows for shrinkage movement in two directions within the slab but allows no vertical movement for load transfer criteria. A plain dowel requires form drilling or slab drilling then epoxy set. For me, there are plenty of times where a simple couple/few smooth dowels are fine and we drill & glue em, but in this case we had a slab to slab Construction Joint for a notable distance and we are hoping the additional feature of sideways slip for shrinkage may help reduce future cracking while allowing decent performance with the forklifts and their hard tires and loadings. Sorry, I didn't get the price of the smooth round dowel with the feature involving the nail onto the form sleeves. And the square dowel with the sleeve doesn't come with a nail onto the form sleeve as it seems to be intended for drilling and epoxy setting. Also for musing: The dowel bar setup that comes with a basket is not used at a Construction Joint and it 'functions / has involvement' with aggregate interlock .... just for commentary because while there is no drilling it isn't really for comparison due to it's different application. Add into the overall recipe that some regions have little shrinkage and/or they choose to not place reinforcing steel in the slab....then these baskets at the (sawn) crack control joints subject to the decision for aggregate interlock alone or a dowel basket in the event the joint opens wider than the aggregate interlock can affect.
That's cheaper than I thought they would be Bob, I was thinking in the $6-8 each range. The ease of installation and less labor makes it a no brainer. Your craftsmanship is spot on, I don't see that quality of concrete forming and finishing very often.
Center bay pour ready for tomorrow and almost closed back the dock wall where we had cut that access passageway. Had to slightly skew the slab saw cut lines as the one row of columns didn't directly align to the other row of columns. The rebar is intentionally set to not "interfere" with the saw cut crack control joints, for example there are no rebar lap joints in any saw cut joints as that would effectively double the restraint in that location. The CMU (speedblock type) wall curb base and block were completed in about 3 hrs using fast set concrete products also sold at HD and fyi these don't use portland cement but instead are made w calcium aluminate related cements. Block to be solid grouted w 3/8" concrete in the cells as soon as we complete concrete floor.
Looks great! Did you break the block cores down to hold the rebar? What was the reasoning going with a CMU wall as opposed to a poured wall thats pinned to the sides?
These blocks are sold as one sees them; notice the no mortar on the vertical butts and the center is indeed low for the 'bond beam' horizontal rebar. Since the (e) dock has a face with block existing, for a quasi "better match" we selected the CMU (concrete masonry unit) in lieu of CIP (cast in place). The horizontal rebars in the CMU are epoxy doweled into the existing block (pinned to the existing wall). ** Some interesting concrete tools: besides the usual wood bull float, a resin float and a magnesium float at around 4', shown in a pic is a channel float and a pan; last pass being put on the slab. The channel float helps with bumps etc after floating and also after panning. 36" pan is the size and this is the bottom side, the other side has cleats which engage the power trowel blades. The pan for the power trowel allows one to get on the slab earlier than std combination blades and helps fill holes etc and make the surface profile with improved flatness (in concrete worker lingo: reduces the mumps/lumps). One more bay (and the dock) to go.
Last bay with rebar, dock block work completed, grouted all cells, backfilled and trimmed edges of dock flatwork to make neat lines. Mini hauled down off the dock. Small curve ball: I had planned to fit the new C channel into the other segments and weld it up w some 7018....then I suddenly realized the segments' disrepair is signified by their movement under any reasonable typical load such as a semitrailer backing in or a forklift crossing and this regular movement will certainly create grief and early demise of the new channel's new concrete....thus I must isolate the new C Channel from these loose pieces and am thinking prolly won't ever weld it to the existing loose segments and will ultimately have to remove them and conduct a repair. Close examination behind the channels (where we can see) shows necked down rebar welded to the channel which likely occurred as a rust rub wear rust rub wear cycle until they were so small they broke. Seems welding the leg of the L gives decent fillet weld length but the radius of that L gives a chance for some flexing whereas I could switch the weld idea to a style similar to a stud weld where the rebar would be butted straight in and not bent .... and yes these are welding grade rebars, a whole $3 more than std grade 40.
I would weld the bar straight into the C- channel like a standard imbed. Let the welded bars extended back into the slab pour several feet if not the distance of the new pour.
I like the 1/4" by 4" strap repair. Why not do something just better enough the whole distance? 3/16 x 2' plate welded to the top of the C channel and bolted to the slab every foot along the edge. Only you'd need to keep the looseness from working the bolts loose, bolt the plate to C channel in a way that allows for that movement, or clean and grout behind that loose channel. Thanks for the concrete education. Very informative.
As to the existing dock with the loose channel, we had to add that strap to keep operations going....for a repair, we will likely cut back the edge (say 2 or 3 feet) of the dock and replace the channel along with the concrete but not possible until this dock has concrete placed, cured and made ready for trucks. BTW those concrete screws don't really perform super good with this type of duty as they loosen in a week or so. So far, they do tighten back up and we hope that patch holds while we get this other dock ready. Here are some pictures of the channel and end caps with eleven #4 *bars on the top row and these are about 3'6" long, and seven #4 *bars about 18" long on the lower row...the *bars at the ends of the channel are attached w/ a flare/j groove weld to the channel cap and the rest of the *bars butt and are fillet welded all the way around w 7018 with great care to create no undercut on the *bar. *Welding grade rebar. Yes, the channel bowed just badly enough (due to the rebar welding) although it was tacked to the other half of the channel as a strongback. To fix: note the rosebud and the water in the sprayer. Heated a few wedges, red hot not necessary nor required and then cooled via the use of the water [to preclude heat soaking]. The load binder with the push-stick cause a modicum of force, just barely enough to shift it into the restraint mode. The formwork is beveled to make the chamfer shape at the underside where it transitions from vertical to the channel's lower horizontal flange. It supports the channel for ht and allows exact adjustment in and out & side to side, and as well for plumb. Details details. Crew will likely pop it back out to clean it up and then paint at least the inner face with some epoxy (same epoxy we applied to the square and plate dowels). After the subgrade is straightened via vibe plate, then the reinstall and finish up the balance of the mat.
Last strip and the dock: concrete placed today.
Got this room scrubbed and cooled down & occupied just before the 4th. Will re-visit and install the low mod epoxy on the crack control saw joints in the off season. Diamonds (squares) at columns [appears as darker concrete in pic as was last item placed] have felt joints, those will receive a self leveling polyurethane. Dock accessory not welded on yet: still on my punchlist. Some painting to do as well. Pic shows the finished job "in use".
That project turned out real nice Bob!
We are working at the produce cooler to finish the temp repairs to the loading dock where the existing 8" C channel has fallen almost off. That strap with the four Titen HDs from Simpson held well but the channel was 'walking' when the forklift passed across = nervous lift operators. Sidebar: The floor is wonderful! I must give credit to the square dowels and the plate dowel. We had a good mix and good curing conditions but west coast aggregate isn't limestone and we get cracks in spite of actions taken to prevent. ~~~ As to the dock repair, we cut sections of the slab and removed the c channels and levelers. Pics show the reachlift carrying the mini & hammer on and off the dock. Reachlift bucket hauled off the rubble and is now hauling off the extra soil. Excavated soil to about 5-6" below bottom of concrete, will compact and bring to grade with Class II Road Base. Anticipating a 10 - 11" thick concrete section near edge of dock. Pic of hole by dock 3 not excavated at the time of pic. How to secure the dock edge C channel? Same as the other one at Dock 2 done when the job done in 2016: approximately 3' long on staggered centers made of welding grade rebars pushed just barely through the channel web by way of rotabroached holes and welded with 7018 inside and outside, then ground flat on the outside. No J bends to make the welds: that typical style of dowels were found under the old channels and had failed by erosion and wear and loss of weld metal. Rebar mat to be double mat: one mat high and one mat low. Bends on end. Gotta get this done in a jiffy so the produce can be shipped across the country and to the cities! Can you guys see the owl mascot in the pic? Some may think it is a real plastic owl LOL.
Nice job there oceanobob We just removed a similar dock but it had plenty of rebar in it...
when the rebar gets bad and circumstances allow, we have been running the aggressive diamond blades and cut it up in manageable pieces....diamond blades cost vs other costs and is more expedient and predictable. That job looks involved due to the size as well as other reasons. Did you have to change that channel? We always have a hard time with the handheldsaws on a wall horizontal cut and we dont have a wall saw - the saw specialists exact a toll on the wallet for their wall work
Are they using a jockey truck to move trailers to and from that dock ? I had a problem with bumper pads being ripped or broken away from the dock. Finally figured it was the jockey truck lifting or setting down the trailer while contacting the pads. The trailer acting like a giant crowbar. The solution was steel faced rubber pads. The metal allowed the trailer to slide yet the rubber absorbed the shock of a trailer impact.
We had to do some cutting with the hand saw but just stuck with an abrasive blade, also had the 120 with a breaker on it for the majority of the work. I also used the breaker on the face of the wall 8" thick I think.... but what really slowed us down was the 5 filled in docklevelers you can probably see where they used to be in the pics, when someone put them in rebar must have been cheap because they used plenty... same with concrete it was well over a foot thick a their bases and a good foot thick all around the perimeter... and when they filled them in they used more rebar and filled solid with crete!!! This was a complete demo so no changing the edge The edge of the dock wasn't too bad I think it was 6 x1/4 or 3/8th angle and they plug welded anchors every foot or two but once you put the hammer behind it or even on it it popped off pretty easy I hear ya' on the saw guys, we sub a lot of wall and slab work out for door cuts on these tiltup's... have one of those stihl ts512 on the little walk behind cart I use for floor cuts up to a hundred or three feet it'll go 6 inches with the 16 inch blade on it but it's a lot slower then a real saw
The trucks are over the road units and they can pull up with 65k and pick up 4 pallets of produce to complete the load....they are backing in and not really going fast but the weight just hammers the bumpers - in the pic you can see a bumper, the bi-fold leveler ramp, then the other bumper. The action of the truck does indeed impart a rotation onto the channel which is why we weld two rows of welding rebar at 12"oc. Will add a pic when we place the channel. ~~~~~~~~~ Concrete around dock pockets can be inordinately thick because of many reasons: the grade tends to slope toward the depression or someone changed the dimension for the pocket and they left the grade low or an engineer wanted bolts of some long length so had to be thick or they didnt have an engineer and "threw" concrete and steel at it. As to cutting, we also have a two cycle saw -a Stihl TS760 (factory fitted for 16" blade) which I bought new a long while ago and is showing some signs of age: carb manifold bolt fatigue crack, blade bearing growling, belt loosens etc. I am getting better at fixing it. Their new saw is the TS800: I bought a 'beater' TS800 from C/List and the power curve is improved (less peaky). They changed the cart so the old cart wont work. Another lark deal: also long ago I had fortunately bought an older at the time 14hp Kohler powered Target saw and it was self propelled and that made a huge diff in the pace of the work and the life of the blade. The motor carb is calibrated for the old school volatile gasoline fuel and the ignition is weak and it is hard to start via a rope start ....so I looked around and found a newer 20hp saw w electric start....also self propelled and that saw runs smooth and takes big cuts.
Same thing with the warehouses we work at, a large portion of the trucks coming in are straight from the port or rail line so the cans are at max gross and sometimes more and there are quite a few drivers that don't know how to slow down before they hit so it just kills these bumpers. the different warehouses have been trying a couple different new style bumpers so we'll see how it goes but anytime you have that much mass being dissipated so quickly I don't think they stand a chance... especially when it happens several times a day We also looked at a job a while back that a lot of the steel edges are failing on the warehouse doors, they have 4 x1/4 inch angle iron with what look to be #5 bar welded every couple feet into the 'v' of the angle iron and was wet set into the floor when they poured it... from what I can tell the damage is coming from their dock plate they use with the forklifts, every time a lift truck goes across it the center supports hammer the top of the steel edge and concrete because it's only the top concrete that's separating not the face of the building... will be interesting to see what happens if they give the go ahead on the job as I already figured we'd have to remove a few feet of concrete behind the door and down probably a foot -- of course if we're doing that then it isn't much more to put in a dock leveler oh well... guess we'll see sometimes it can take years for the powers that be to make up their minds on what to spend where. The only trucks that back into these doors are hauling brown cardboard boxes that get distributed to amazon fulfillment centers and they all use those regular portable dock plates.
That angle in the process of falling off is sure discouraging - but those forklifts work the heck out of the concrete. The pics show how we had to weld the rebar through the channel and we did two rows. I was reading on some federal highway publication that dissuaded the use of a bent piece of rebar with two fillet (j groove) welds to hold the 'tang'. Apparently this method allows some miniscule motion whereas a straight through rebar connection does not. And I use the old standby: 7018 When I buy rebar for welding, I always spec Welding Grade with the W stamp. We also coated the inside face with that epoxy made by Sherwin Williams called macropoxy. A few more rebars to tie, then a shutter with a cant under the c channel, and we are ready for concrete.
I can see where a through piece of rebar would be stronger. The rebar would have to shear through instead of just a weld. Nice work Bob!
The concrete mix was 4000 in 28 days, had 5.5 sacks cement, 0.5 sack of flyash (about 9%), aggregate is "blend mix". Blend mix means we add a little more aggregate from the 3/8" plus bin in addition to what is already in the 3/4" plus bin. This material has to be boom pumped or line pump with min 3" hose. Finer aggregate concrete is not a very good solution for commercial/industrial and forklifts which are the nemesis of decent concrete. Forklifts were permitted to drive across the patch slab within three days of placement because we kept the water out by using a high range water reducer and the temps are warmer. About the welding and the dock levelers and the trucks....we waited about 2-1/2 weeks for higher strengths and concrete to dry out so we could weld onto that channel which is intimate with the concrete. They would have liked it done sooner but the business typically doesn't get crazy busy until the first/second week of July. So yes, they were quite glad to have another dock for the trucks that are hauling off the produce. The dock leveler at bay 3 hangs a little low: it needs a spring on the knee to be adjusted. Moving these things and aligning them on the forks prior to positioning is nerve wracking - for sure finger pincher stuff - because they will quickly flop (the thing is a giant three piece hinge but with a knee - to operate, they pull up on the second 'fold' or stick a pipe in order to lever it into position ... the knee flips into position and the outer segment kicks out and lands on the truck....when the truck pulls away, it fall to the hang position). Not for the unaware to handle these. Good ole Powcon and some 7018 Excaliber stitched it onto the channel. While we were there, got a chance to practice some flame straightening but elected to invoke a modicum of restraint since the plate is kind of a free from object - thus the bowstring chain and binder. The flame straightening method involves rapid heating then cooling in order to astutely shrink the metal on one side but not the other. The pattern and the heating time is critical and the piece is best brought back to dead cold before the next attempt, none of this was a issue as we had plenty of jobs ..... heat and water cool a couple times, then let it rest. The flame straighteners supposedly can accomplish this and work miracles. Neophyte at this: we typically had invoked brute force or redhot with a torch. That piece had big warp on the one corner and it is pretty good now. The process admittedly takes some patience - sometimes think I might be heating too much: have to get a temperature crayon to try and determine temp achieved and learn how fast to move the rosebud. The rosebud is pretty good sized and I recall having to get a larger acetylene in order to provide the draw rate. Supposedly should be able to perform this task without heating higher than a dull red color which quickly fades once the torch is removed. Rapid cooling with water is intended to gain the maximum shrink - notice the wet concrete in the pic. ~~~~~~~~~~~~~ All cleaned up and ready for trucks.
Look into changing over to propane for your rosebud. If you find a LWS who knows there stuff a propane rosebud of the same size as an acetylene one will give you about 3 times the btu's. I use propane for heating as it is much more efficient.
My original reading about Flame Straightening is from the Lincoln welding book (that big thick book). It describes methods to develop a sharp difference in the heated vs cool areas. I recently obtained two more texts: one that has a chapter on this topic and then I also got the book Flame Straightening Technologies. It appears the use of a rosebud can be improved by using a cutting torch tip due to the heat intensity (more focused). Maybe will start a new thread (if) as I make progress with this topic.
A heavy beam clamped/tacked underneath, some heat and a couple big Bessey clamps would work for straightening a plate like that too. Applying the heat from the bottom would make a difference too because it will pull more to where the heat is concentrated when it cools.
I've seen a few of these dock seals getting ripped off by truckers lately... and they aren't even very old??? either the truck drivers are getting more aggressive or they have found a new way to backup!!! These things used to be just about bulletproof until the wood frame rotted!!! Also pulled off a bunch of premade Frommelt side bumpstops cause they were replacing them with 'better ones' heh heh we'll see how long the new ones last
Durn Trucks … I had a problem of the trailers tearing the rubber stop pads off the docks. Figured out the real problem was our OTTAWA Yard truck. It had a hydraulic 5th wheel. With the trailer against the rubber stop, when the OTTAWA either lifted or dropped the trailer, it acted like a crowbar. Solved the problem by covering the rubber with metal plates. The trailer then slid against the metal clad stop, instead of tearing it off the wall. Without the rubber stop, the trailers beat the dock edge to bits.