DFI Helical Foundations & Tieback Committee Meeting
New Orleans, 11/16/07
By Rich Davis
Editor-in-Chief
The DFI Helical Foundations & Tiebacks Committee Conference was held last on Friday, November 16th at the Chateau Sonesta Hotel and Conference Center in New Orleans, Louisiana. The one day conference experienced a significant decline in attendance when compared to last year’s conference in Newark, NJ. DFI sources placed this year’s attendance at approximately 50 people as opposed to last year’s 100+.
Although HPW did not attend this year’s conference, some in attendance reported that the quality of presentations was really quite good and very informative. Three notable presentations were given by Dr. Amy Cerato, (University of Oklahoma) titled “Designing Small Wind Tower Guyed Cable Foundations Using Helical Anchors Subject to Dynamic Loads”, by Dr. Howard Perko (Magnum Piering) titled “Seismic Loading, Case Studies in California”, and by Gary Seider, P.E. (Chance Civil Construction) titled “Helical Anchors Help Clean Up Creosote Plant on Bayou Bonfouca in Slidell, LA. The first two presentations offered forward looking insight into potential new applications for helical piers, while Gary Seider’s revealed a unique twist to what was supposed to be a temporary bayou shoring project.
Dr. Cerato’s presentation focused on the potential for using helical anchors to anchor wind turbines and thus replacing the costly and time consuming concrete “deadman” anchoring systems currently being used. Her presentation focused not only on dynamic wind load testing, but also on the effects that ground water can have on helical pier capacity – a situation that presented itself at her test site. Another interesting aspect to Dr. Cerato’s project is her “Research Team” comprised of students at Oklahoma University enrolled in their civil engineering masters program.
Dr. Perko’s presentation on Seismic Load in California featured case study information from long time helical advocate Stan Ruppiper, P.E., an engineer based in California, who has studied and promoted helical piers for several decades. Dr. Perko integrated Ruppiper’s empirical evidence on the benefits associated with foundations supported by helical piers during earthquakes in California along with Perko’s own calculations based upon the International Building Codes. Dr. Perko also drew some correlations and conclusions on the net effect of Damping as published by Tabesh and Poulos, 1999.
Gary Seider’s presentation on the construction of a sheet pile retaining wall with helical pier tiebacks portrayed a very successful “temporary shoring project” that is still in place today - some 14 years after installation. The retaining wall was put in place to facilitate a dredging operation to remove massive amounts of contaminated soils that had leached from a creosote manufacturing plant site into the nearby Bayou Bonfouca near Slidell, LA.
All three of these presentations as well as others presented at the conference should be available soon at the www.dfi.org website.
Helical Pier World
