Thanks for the feedback. The 8” floor and 2’ mat span across 3 hefty steel beams. I definitely checked that first.
Good feedback on the HES concrete. The mix design proposed is a Highway mix, so it has quick usage history. One point mentioned is the bond between the machine grout and the...
I have a dilemma where the client wants to set a dynamic piece of equipment on a 2' thick concrete pad that is doweled onto an 8" thick elevated floor (second floor) only 1 day after setting the concrete. He is proposing high early strength concrete that is shown to achieve 3900 psi after 24...
My brothers foundation in Dallas has a similar issue. They waited over a month to tension the cables. The house was fully dried in but no brick or sheetrock yet. The crack was probably over 1/4" to 3/8" wide. They stressed the tendons and the crack only minimally closed. They sent the...
Yeah, you guys have confirmed what I read previously, that movement is a very big concern and can damage the machine. I hit shale at 4' below grade per the soils investigation. The soils guy introduced me to a micropile contractor, but I'm thinking if my total slab thickness is 7', I'm well...
Thanks, Hturkak! Yeah, the unbalanced forces are not large at all. Yes, with the combined upper block and lower raft (plinth), I'm definitely into the shale enough for firm resistance. I agree with you that the underpinning may be a little overboard, but I will analyze both ways (with and...
Yeah I was thinking the 100 lbs/si/in was a little low. I think it's stiffer than that. The micropile consultant says we can get some pretty stiff springs with the micropiles. Thanks for the feedback folks. I really appreciate it. As usual, the clients wig out with robust structures, but...
Attached is the press foundation snapshot.
https://files.engineering.com/getfile.aspx?folder=1c138505-0024-4328-a48c-f37386660059&file=Printing_Press_Foundation_Snapshot.pdf
I also uploaded a snapshot of the press foundation with block and plinth combination on micropiles. Maybe a bit of overkill, but can always scale back in conservatism later. Basically the bottom of the plinth (lower foundation) is into the shale. So, may not need the micropiles at the end of...
The modulus of subgrade reaction, k, is 100 lbs/per si/in. And the SPT-N values when you get to shale at 4' depth is 50 blows per foot roughly. I have a top block of 9' width x 4' depth (machine is around that width) and I added a plinth underslab (plinth) of 17' width x 3 foot depth that is...
I've not designed a foundation for a printing press. This one is for a client in Arkansas. The soils are good. Low PI and shale at 4' and beyond. Allowable bearing is around 2500 psf and expected settlement for shallow rigid foundations is less than 1", but the differential settlement...
Thanks guys. Good points for sure. There is no seismic activity down here in southeast Texas, so I did not include those parameters. It may be good practice to follow those regardless. I did go ahead and install some horizontal diagonal braces in a diamond pattern around the perimeter of the...
I mislabeled the braced chevrons, so I reuploaded my views for clarification of where the unbraced chevrons are.https://files.engineering.com/getfile.aspx?folder=2ac8f93b-6c38-4f8e-b0b2-d0159ab881ed&file=Intermediate_Chevron_Bracing-2.pdf
I have a vertical vessel supporting structure with an intermediate section that does not allow cross bracing at the chevron braces. I modeled it in Risa3D and used a compact W10x33 primary chord that spans 16' in the long direction. To account for no lateral bracing, I used the full member...
WARose...thanks for the quick feedback. That’s my thinking as well, just needed feedback from another source. This is in the major axis direction. In the minor axis, my gusset grabs plenty of baseplate and web, since I don’t have a middle anchor in that direction.
We use standard connection...
I have a typical chevron braced four level industrial structure that’s 10’ x 16’ base with four W12x65 columns. Supports a vertical vessel supported at the third level.
I’ve got a base plate with six bolts, three each outside the flanges. Since there’s a bolt at the center of the flange, I’m...
Thanks, retired13. Only real concern is the condition of the 70 year old pavement, which has got some wear and tear (cracks; rebar condition?) and soil condition below slab. They’ve had some fluid collection (spillage and rain) and not sure about potential washout of soils (clayey sand; SC...
retired13....That’s basically what I was considering initially. I had an 8” thick pad anchored/doweled into a 6” thick pavement. For a centrifugal pump, I need concrete total mass that is two to three times mass of pump. I have two times mass if I consider composite/combined pad and pavement.
I do have good info on the paving. It's 6" thick with double layer of steel (#4 at 12" each way top and bottom). But the surface has gotten beaten up over time (old 1950 era plant).
