Synthesis of Load-Deflection Characteristics of Laterally Loaded Large Diameter Drilled Shafts: Technical Report
Author(s):
J. Briaud, Y. Wang
Publication Date:
November 2018
Abstract:
This project evaluated how well current P-y curves predict the behavior of large diameter piles subjected to monotonic lateral loading. Current P-y curves were developed about 60 years ago based on lateral load tests on piles, which were about 2 ft in diameter, while today's pile diameters can reach 12 ft. This significant difference in scale brings into question the application of these early P-y curves to today's large diameter piles (=5 ft). A database of 35 piles with diameters larger than 5 ft (up to 9.8 ft) and 54 piles with diameters less than 5 ft both in sand and in clay was assembled. Predictions of load and displacement are carried out using P-y curves and LPILE. These predictions are compared to the measured loads and displacements. In sand, the ratio of predicted load over measured load Lpred/Lmeas averages 0.9 for all piles and increases with diameter from 0.7 for smaller diameter piles to 1.1 for larger diameter piles. Overall, Lpred/Lmeas is between 0.4 and 1.4 most of the time. In clay, Lpred/Lmeas averages 0.9 for all piles and decreases with diameter from 1.3 for smaller diameter piles to 0.7 for larger diameter piles. Overall, Lpred/Lmeas is between 0.4 and 1.6 most of the time. In sand, the ratio of predicted deflection over measured deflection ypred/ymeas averages 1.9 for all piles and decreases with diameter from 2.25 for smaller diameter piles to about 1 for larger diameter piles. Overall, the ratio ypred/ymeas is between 0.5 and 5 most of the time. In clay, ypred/ymeas averages about 1.4 for all piles and increases with diameter from 0.9 for smaller diameter piles to 3 for larger diameter piles. Overall, ypred/ymeas is between 0.2 and 5 most of the time with some values reaching 8 for larger diameter piles.
Report Number:
0-6956-R1
Electronic Link(s):
Document/Product
http://tti.tamu.edu/documents/0-6956-R1.pdf
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