Pile design

[AUCE98]

I have been asked to design a residential home on elevated piles. The project is located in Mass, along the coastline. My intent is to design the piles using Lpile, however, I have a question regarding the lateral loading. Can anyone point me to a reference that provides the proper loading for waves/flooding?

Also, would using a program such as Lpile for this type of project be the typical method of design, or is there another method available?

Thanks,

AUCE98

 

[jdonville]

AUCE98,

I would think that LPILE would work very well for the lateral load response analysis. You will still need to check the geotechnical capacity of the pile under vertical compression and uplift loads separate from the LPILE analysis.

Don't forget to include wind loads (transferred from the structure) along with wave loads (on the pilings) in your load cases.

Jeff

 

[shin25]

If your layout allows, you should try to use some battered piles with plumb piles to take up the horizontal thrust. This will considerably reduce the moment demand on the piles due to wind or earthquake loads.

 

[twinnell]

It was my impression that the residential builiding code covered the design of these elements, as long as they fall within the prescriptive requirements. I think there are some coastal design guides floating around the web as well. Maybe even free.

 

[csd72]

ASCE7 has a section on waves and water loads.

There is a fema document on coastal buildings that should also be followed for this.

csd

 

[SlideRuleEra]

The primary FEMA document is "FEMA 55, Coastal Construction Manual". It comes on a CD and may be ordered for free from FEMA - you should get it in a couple of weeks... or you can download the .iso file from my website and create an exact copy of the CD, follow the links here
Thread194-174585

http://www.SlideRuleEra.net

 

[msquared48]

It's not just the waves, but also the debris in the waves - particularly large logs. You might consider a debris barrier in front of the piling if that is possible. Otherwise, consider more vertical steel and ties.

I believe the US Navy has a TM, or whatever they call it, on wave loadings - I think I have a copy, but will have to look for it in my archives. I have used it in the past for loadings on floating pleasure dock systems.

Mike McCann
McCann Engineering

 

[TonyES]

I can't help with the loadings but I would recommend using GROUP4.0 or even a newer version of it. It allows multiple piles to be analyzed and in my research was more accurate than Lpile.

 

[shin25]

I have not used L-pile myself, but have seen that the vertical and the transverse analysis of the frame is performed by some other software like staad, etc. The results (shear, moments, vertical loads etc) from this analysis are used as input for L-pile. I am not sure why, but sounds like L-pile cannot perform these calculations.

 

[jdonville]

shin25,

LPILE is used for the geotechnical analysis of single piles under lateral loads and/or moments. Axial loads may be input to provide a first-order p-delta correction and to accurately model the state of stress within the pile section. LPILE provides an improved user interface and more cases over its public domain ancestor, COM624P.

Other less complex methods or software should be used in conjunction with LPILE to analyze the structural moment, shear and axial capacity and geotechnical axial capacity of single piles.

TonyES is correct in that GROUP will perform analyses for groups of piles, and likely uses the functionality of LPILE and SPILE (axial capacity) code (all 3 products have the same developer) for use in developing initial single pile results that feed into the multiple pile results.

Jeff