Lateral Pile Cap Load Tests with Gravel Backfill of Limited Width

Download or read book Lateral Pile Cap Load Tests with Gravel Backfill of Limited Width written by Kyle M. Rollins and published by . This book was released on 2010 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study investigated the increase in passive force produced by compacting a dense granular fill adjacent to a pile cap or abutment wall when the surrounding soil is in a relative loose state. Lateral load tests were performed on a pile cap with three backfills to evaluate the static and dynamic behavior. One backfill consisted of loose silty sand while the other two consisted of dense gravel zones 3 ft. (0.91 m) and 6 ft. (1.82 m) wide between the pile cap and the loose silty sand. The 3 ft. and 6 ft. wide dense gravel zones increased the lateral resistance by 75% to 150% and 150% to 225%, respectively, relative to the loose silty sand backfill. Despite being thin relative to the overall shear length, the 3 ft. and 6 ft. wide gravel zones increased lateral resistance to 59% and 83%, respectively, of the resistance that would be provided by a backfill entirely composed of dense gravel. The dynamic stiffness for the pile cap with the gravel zone decreased about 10% after 15 cycles of loading, while the damping ratio remained relatively constant with cycling. Dynamic stiffness increased by about 10% to 40% at higher deflections, while the damping ratio decreased from an initial value of about 0.30 to around 0.26 at higher deflections.