Resistance factors for 100% dynamic testing, with and without static load tests.

Details

• Creators:
  McVay, Michael ; Klammler, Harald
• Corporate Creators:
  University of Florida. Dept. of Civil and Coastal Engineering
• Subject/TRT Terms:
  CAPWAP Concrete Design Load Distributions (Statistics) EDC Girder Bridges Ground Settlement Load Factor Load Limits Load Tests LRFD F PDA Pile Groups Pile Monitoring Prestressed Concrete Bridges Random Variables Reliability Reliability (Statistics) Tolerance (Physiology)

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• Resource Type:
  Tech Report
• Geographical Coverage:
  Florida
• Edition:
  Final report; 09/24/09-06/30/11.
• Corporate Publisher:
  Florida Department of Transportation
• Abstract:
  Current department of transportation (DOT) and Federal Highway Administration (FHWA) practice has highly
  
  variable load and resistance factor design (LRFD) resistance factors, Φ, for driven piles from design (e.g., Standard
  
  Penetration Tests (SPT), Cone Penetrometer Test (CPT)) to construction (e.g., pile monitoring). Complicating the
  
  construction effort, are the number of piles monitored (e.g., 10% versus 100%), as well as the type of monitoring (e.g., high
  
  strain rate: Embedded Data Collector (EDC), Pile Driving Analyzer (PDA), static load test, etc.). Of great interest are
  
  quantifying the influence of number of piles within a group, number of piles monitored, as well as spatial variability on a
  
  pile group’s uncertainty and associated LRFD Φ factors.
  
  The work started with an investigation of probability of failure (POF) of a bridge in terms of its piers and underlying
  
  piles. It was discovered that the number of piles in a pier may have a large impact on POF of a pier, which is why the
  
  development of LRFD Φ should occur with respect to pier (i.e., pile group) level and include the total number of piles
  
  within the group as well as the distribution of monitored and unmonitored piles within the group. Next, the total
  
  uncertainty of the pier including spatial variability and error of the method (e.g., SPT, EDC/PDA, etc.) was investigated. The work started with spatial uncertainty of single pile resistance (side plus tip) from SPT data and then extended through
  
  kriging (considering different weights for individual borings) to group layouts (e.g., double, triple, quads, etc.) for assessing
  
  group resistance uncertainty, CVR. Subsequently, the kriging group work was carried over to assessing uncertainty, i.e.,
  
  spatial and method error (predicted versus static load test) for high strain rate field measurements. Equations and charts
  
  were developed to quantify group uncertainty, CVR, and LRFD Φ for typical group layouts and monitoring. The latter
  
  approach was considered to be inflexible, and the spatial uncertainty (i.e., kriging) was replaced with hammer monitoring
  
  in conjunction with high strain rate monitoring. Using the uncertainty of monitoring method (CV εm) and a measured
  
  uncertainty of blow count regression (CVεh) versus high strain rate monitoring, an LRFD Φ equation was developed for pile
  
  groups considering the numbers of monitored and unmonitored piles. The developed expression was evaluated at two sites
  
  and gave reasonable predictions compared to current practice.
  
  
• Format:
  PDF
• Funding:
  BDK-75-977-25
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:6a54db2f2771f637c9c8190e63403c83015946aacd53caf95bed2055ce9a72c4
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/20543/dot_20543_DS1.pdf
• File Type:
  [PDF - 1.33 MB ]