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Deep Foundations Institute Helical Piles & Tiebacks Committee is Successful in Obtaining $34,000 in Funding to Launch a Pilot Study on Helical Pile Behavior in Soils Susceptible to Liquefaction from Seismic Events
by Bill Bonekemper
Deep Foundations Institute (DFI) Helical Piles and Tiebacks Committee (HPTC) Chairman, Gary Seider, recently announced that the (DFI) Technical Committee Projects Fund Selection Committee has agreed to provide $20,000 towards the proposed liquefaction study submitted by Ramin Motamed, Ph.D., P.E., Assistant Professor University of Nevada, Reno.
Ram Jack Systems Distribution Donates $14,000
Soon after the DFI funding announcement, Ram Jack Systems Distribution, Ada, Oklahoma, offered to donate an additional $14,000 to have the proposed study fully funded. “Our executive committee reviewed Dr. Motamed’s study proposal, and we determined the study is an essential component in HPTC’s overall effort to evaluate the effectiveness of helical piles when they are subjected to seismic forces,” said Ram Jack engineering director, Darin Willis. “Without fully funding the proposed study, Dr. Motamed would not have the necessary funds to conduct comparative tests with other foundation types such as concrete piers, and our executive committee felt such comparative tests are essential to the overall understanding of how helical piles perform relative to other piling systems,” Willis added.
The proposed study will include scaled laboratory testing of helical piles and other pile types at the University of Nevada, Reno Department of Civil and Environmental Engineering. The entire study is scheduled to take one year to complete, and Dr. Motamed’s efforts have already begun. The results will be documented and compiled into the format of a journal paper for submission to the DFI Journal.
Dr. Motamed’s Study Abstract
The main objective of this research is to experimentally evaluate the performance of helical piles as an alternative solution in mitigating the settlements of shallow foundations in liquefiable soils. Post‐disaster reconnaissance of areas affected by the earthquakes have documented extensive damage to shallow foundations of structures within liquefaction prone areas. For example, the 2010 and 2011 earthquakes in New Zealand caused severe and widespread liquefaction throughout the town of Christchurch and subsequent damage in more than 20,000 residential homes.
Helical piles could be a cost effective solution for retrofitting low story buildings in areas susceptible to liquefaction. In addition, helical piles have the benefit of fast and easy installation with minimal equipment. Installation is considered low-impact, low-disturbance and can be employed in low overhead conditions. Therefore, this research aims at evaluating the seismic performance of helical piles underpinning shallow foundations located on liquefiable soils.
Our research focuses on conducting an extensive series of experiments using the 1-g shake table facility at the University of Nevada, Reno (UNR) to study the seismic response of helical piles in liquefied soils. The results of the study will be used to inform countermeasures to reduce building settlements in such events. This research is divided into two main components: (1) to validate scaled shake table experiments using the data from the recent large-scale shake table experiment at UCSD, (2) to carry out an extensive series of experiments to evaluate the behavior of helical piles in liquefied soils. The proposed experimental research includes a comprehensive parametric study to quantify the effects of several parameters on the efficiency of helical piles to mitigate liquefaction-induced building settlements. The following sections further detail the experimental program.
DFI - HPTC Secretary