Pile Cap Design Software

[dengebre]

I am looking for a good pilecap design program and was wondering if anyone had any recommendations. I would prefer a program that uses a FEM solution to determine the pile cap forces, pile reactions, design the reinforcement, etc. Thank you in advance for your advice.

 

[mike20793]

I've had good luck with SAFE. It's a little tricky to model with, but once you figure it out, it's not too bad. The minimum reinforcement checks need to be done by hand, but the CRSI handbook helps out with that. SAFE will not size or design the piles; we have in house spreadsheets for that.

 

[Hialoha]

Not familiar with SAFE, but when I use RAM CONCEPT to model a pile caps supporting shear walls, the piles directly under the wall receives the most portion of the loads. Did you notice the similiar result from SAFE? But when we design a typical pile cap, we normaaly assume pile cap as rigid and evenly distributes the gravity load. I know FEM is more realistic compared to rigid assumption. But how deep is deep enough to use the rigid assumption for the hand calculation.
Especially whne I design high-rise building pile cap with lots of piles supporting the elevator core under lateral loads: the moment from the very edge piles to the face of wall above is very big and requires deep pile cap-say 8ft. But it just looks like too deep.

 

[mike20793]

Yes, you will get similar results from SAFE. RAM CONCEPT is nice because you can bring your loads directly from RAM. When using SAFE, you have to figure out how to apply the loads by spreadsheet input; it's difficult the first time, but easier after that. 8 feet thick may not be that unreasonable depending on the loads and number of levels.

 

[Hialoha]

Thank you, Mike20793.
Does the SAFE check the deep shear per CRSI or conventional ACI shear? I know ACI shear is too conservative for the deep cap.
Also I know deep shear per CRSI has much better shear capacity; how about the moment? Do you use conventional beam concept or struct and tie for the moment check? Or which SAFE is using?

 

[mike20793]

I believe SAFE uses the provisions of ACI, but I follow CRSI for flexure design. It depends on my caps whether I use strut and tie or conventional beam theory. The vast majority, I use conventional beam theory, but I just had a project where I designed around 20 pier caps with strut and tie; they supported columns, so it was shear that controlled and there were concentrated loads. If it's an elevator or stair shaft, it's not likely that shear will control and I will almost always default to conventional beam theory. I will avoid strut and tie at all costs. There are only a couple programs that I know that will do strut and tie and they are all 2D models that basically need some hand calcs to get the geometry correct.

 

[tgeng21]

I have used a simple to use yet powerful software called TGPILES. One needs to provide axial loads and bending moments for DL,LL, WL and then software designs the pile cap and its required reinforcing.It also checks to make sure the pile spacing is appropriate for the pile capacity and also designs a new pile cap for any misplaced piles in the field. The nice thing about this software is that one does not need to interpret stresses from a finite element program and all the design is done for the cap per ACI 318.

 

[JoshPlumSE]

dengebre -

You might want to check out the RISAFoundation program. Or, download the free demo from our website:
[URL unfurl="true"]https://risa.com/p_risafoundation.html[/url]

I don't want to go into too many details here. But, if you want FEM or closed formed solution for pile capes, RISAFoundation will do both. Essentially, it has a library of predefined pile caps based on the layouts from the CRSI manual on pile caps. The design of these pile caps will be per standard closed form design procedures. However, if you have layouts that don't match you can create them as pile supported mat slab foundations which are analyzed based on an FEM solution.

Therefore, you have the opportunity create the pile cap using both methods to validate the accuracy of each method against the other.

I'm certainly not criticizing SAFE or Concept, but my belief is that most people will find RISAFoundation easier to use.