Limiting the bearing capacity
Limiting the bearing capacity
(OP)
Hello
Do you ever limit the allowable bearing capacity to a lower value? For ex from 10 bars to 4 bars
Do you ever limit the allowable bearing capacity to a lower value? For ex from 10 bars to 4 bars





RE: Limiting the bearing capacity
RE: Limiting the bearing capacity
the project i am referring to is a 9 storey building with 4 underground parkning lot
RE: Limiting the bearing capacity
RE: Limiting the bearing capacity
RE: Limiting the bearing capacity
What if the structural egr is comfortable designing in the 2 to 4 bar region because he/she accepts there will be construction defects and wishes to minimize those impacts? Or the structural has a tight budget and never signed up to redo their details and check them against higher stress concentrations? Or they've already gone down the road with the design and don't see a big enough benefit to the project to optimize. Don't expect the structural engineer will say they took this approach to the project team, they will just put the number down on the project plans and sleep super-well at night knowing the "secret safety factor" protects them alone if forensic review were ever needed and since it will be hard to mess it up that much the Owner is protected in the process. Meanwhile, the testing/inspection firm is out there recommending undercuts and freaking out left and right anytime something doesn't exactly match the expected conditions from the soils report.
RE: Limiting the bearing capacity
RE: Limiting the bearing capacity
Anyway, i know the bearing capacity will influence the foundation design but it doesn't effect the structural design right ? only the settlement especially the differential type is important in that regard .
And let me tell you i work for a laboratory that conduct only tests and gives the allowable bearing capacity just for the record . We don't get in touch with the structural firm often.
RE: Limiting the bearing capacity
I'll limit allowable bearing pressure also based on serviceability considerations - i.e., settlement criteria.
There's also the entire realm of reliability - I mean how often do we actually know the full story. . . ?
f-d
ípapß gordo ainÆt no madre flaca!
RE: Limiting the bearing capacity
RE: Limiting the bearing capacity
Could you guys reply to my last question about the impact of bearing pressure limitation on structural design ?
@Okiryu the philosophy here where i live doesn't and probably will never raise to that level of professionalism , many people ignore what is true geotechnical engineering
RE: Limiting the bearing capacity
I work for the U.S.'s third largest DOT. I manage the geotechnical program for our statewide program and I also manage the consultants that work on our projects. I receive all the design-build geotechnical submittals (well with few exceptions). You have no idea how often I see laboratories submit certificates that include extraneous information, "As a service." I reject all these certificates! If I allow any design engineer to rely on the free service, then I get dragged into the liability. I won't do that! So, if a laboratory certificate for a consolidated-undrained triaxial strength test (with pore pressures) returns a cohesion intercept and a friction angle, I reject that or I require that a professional engineer stamp the certificate. ASTM considers the Mohr-Coulomb failure envelope a professional service. We all acknowledge that firms that only provide laboratory testing are not providing a professional service. It's a very important service, but it's not engineering. The assignation of failure criteria is related to strain compatibility and soil-structure compatibility. Now, if folks don't know that, that's o.k. . . we do. If folks try to make it like it's not relevant, I don't buy it!
I let the engineers do what the engineers are supposed to do and I let the labs do what the labs are supposed to do. We procure engineering services on a time and materials basis and we procure testing on a unit cost basis. These imply different levels of service.
I have no problem limiting bearing pressure. I just can't write up all the reasons an engineer may elect to do that; however. Mostly because engineering is complicated!
f-d
ípapß gordo ainÆt no madre flaca!
RE: Limiting the bearing capacity
We then go on by assuming a strip footing in most cases with dimensions 1x1 m and conduct the analysis with any available method . And mind you we do know field conditions since we conduct the borehole tests
RE: Limiting the bearing capacity
Wow!
f-d
ípapß gordo ainÆt no madre flaca!
RE: Limiting the bearing capacity
RE: Limiting the bearing capacity
RE: Limiting the bearing capacity
Also you wrote: "the philosophy here where i live doesn't and probably will never raise to that level of professionalism , many people ignore what is true geotechnical engineering" I see you have passion for what you are doing, and I think that you now have chances to make people know what is true geotechnical engineering, it will be a slow process, but failure/costly repairs/expensive designs happen, so at the end people will understand you. Good luck!!