Studies of seismic and impact loading on foundation piles is an important and a focused interest in the engineering world today. Because of seismic and other natural events are unpredictable, uncontrollable and potentially unsafe it is a vital study to understand the behavior and relationship structures in motion have on there foundation. Statnamic Loading has become a popular method of studying this relationship in a controlled environment. Two groups of 9 and 15 driven hollow pipe piles were tested in saturated clay at the Salt Lake City Airport in July of 2002. The 9-pile group (3x3 configuration) was separated at 5.65 pile diameters and the 15-pile group (3x5 configuration) was separated at 3.92 pile diameters. The testing consisted of five target deflections. Each target deflection consisted of 15 cyclic lateral static loadings and a 16th lateral statnamic load. This study focuses on the statnamic loading. Damping ratios ranged from 23 to 50 percent for the 15-pile group and 29 to 49 percent for the 9-pile group. Both pile groups increased in damping as the deflections increased. The optimized mass in motion for the entire system was found to be roughly 21,000kg for the 15-pile group and 14,000 kg for the 9-pile group. Stiffness for the 15-pile group started at 50kN/mm and ended at 21kN/mm. The 9-pile group ranged from 28kN/mm to 12kN/mm.



College and Department

Ira A. Fulton College of Engineering and Technology; Civil and Environmental Engineering



Date Submitted


Document Type





statnamic, piles, pile, lateral, foundation, dynamic, full-scale, Broderick, Rollins, BYU, thesis, engineering, damping, stiffness