Synthesis of Load-Deflection Characteristics of Laterally Loaded Large Diameter Drilled Shafts: Technical Report

Details

• Creators:
  Briaud, Jean-Louis ; Wang, Yen-Chih
• Corporate Creators:
  Texas A&M Transportation Institute
• Corporate Contributors:
  Texas Department of Transportation. Research and Technology Implementation Office ; United States. Department of Transportation. Federal Highway Administration
• Subject/TRT Terms:
  Clay Deflection Diameter Dislocation (Geology) Evaluation And Assessment Load Tests Mathematical Prediction Pile Foundations Piles (Supports) Sand
• Publication/ Report Number:
  FHWA/TX-18/0-6956-R1
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States
• Edition:
  September 2017–August 2018
• Corporate Publisher:
  Texas A&M Transportation Institute
• 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.
• Format:
  PDF
• Funding:
  Project 0-6956
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:46d0a0b3e8e78042b251d548884735f8397106748592ab99ea9cd094a09601a1
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/64548/dot_64548_DS1.pdf
• File Type:
  [PDF - 16.14 MB ]