Pile group program (simpler than GsRaft)
Chris Raison - Raison Foster Associates commented
I think you are missing the point a little. GSA is very good at modelling the pile cap or raft part of the system and I agree that there is a need in GSA to be able to more accurately model piles. But what Oasys is missing is a geotechnical pile group program (cf PIGLET and REPUTE). The important issue here is the interaction between piles through the ground, whether this is due to vertical or horizontal load.
What is required is something more rigorous than PIGLET with a better geotechnical model of the pile (axial and lateral), but much simpler and more user friendly than REPUTE. It is required to resolve pile group vertical, horizontal and moment loading into pile loads (torsion as well but this is rarely a practical issue and could be ignored).
PILE already includes an estimate of settlement at a specified radius from the pile in question. It should be relatively easy to sum up all effects from a group of piles and work out a group settlement effect for a flexible pile cap. Or adjust the head load on individual piles in a group to get the same settlement to model a rigid pile cap. Pile group moment could also be modelled as a varying vertical load across a pile group.
ALP is much more difficult as currently it does not include any interaction effects between adjacent piles. But this is a more important effect for bridge abutments or wind turbines where there is a significant shadowing effect between piles (ie adjacent piles are embedded in soil that is moving due to load on another pile, therefore needs to move more to mobilise resistance, or mobilises less resistance for the same movement.
Neither of these geotechnical issues will be covered by a GSA enhancement.
My preference would be for a standalone software that links to PILE and ALP data files (and possibly GSA) for the key calculations and avoids overly complicating PILE or ALP which at present are simple and easy to use. (Well ALP is, PILE is getting rather complicated these days).
Peter Debney commented
We are looking to add the pile soil interaction curves from Alp and Pile into GSA.
I think this is much more achievable than a completely separate program when the hard work has already been done in GsRaft. I'll take this idea forward with the structural team. Thanks Adam.
Adam Pickles commented
A decent pile group analysis program is required, but this would seem to exist in GSRaft. We need more advice on how to use GSRaft to model pile groups. Perhaps with tools to create the Pile Soil Interaction Curves and otehr input data (perhaps derived from ALP piles, PILE files etc)