Calibration of Resistance Factors for Driven Piles Using Static and Dynamic Tests
Calibration of Resistance Factors for Driven Piles Using Static and Dynamic Tests

Author: Deshinka Arimena Bostwick

Publisher:

Published: 2014

Total Pages: 234

ISBN-13: 9781321400434

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The field of geotechnical engineering has evolved from Allowable Stress Design (ASD) to Load Factor and Resistance Design (LRFD) which has led to a need to quantify the measures of uncertainty and the level of reliability associated with a project. The measures of uncertainty are quantified by load and resistance factors, while the level of reliability is driven by the amount of risk an owner is willing to take and is quantified by the reliability index. The load factors are defined through structural design codes, but the resistance factors have uncertainties that can be mitigated through reliability based design. The American Association of State Highway and Transportation Officials (AASHTO) have recommended resistance factors that are dependent on the type of load tests conducted and are available as a reference to state agencies. The objective of this study was to improve the AASHTO recommended resistance factors used by the Arkansas State Highway and Transportation Department (AHTD), thereby, increasing allowable pile capacity and reducing deep foundation costs. Revised resistance factors for field acceptance based on dynamic testing were established through the analysis of pile load test data where both static and dynamic load testing was conducted. Pile load tests were separated by pile type and soil type. It was important that the load test data analyzed represented soil and geologic conditions similar to those found in Arkansas. The resistance factors determined from this analysis improved AHTD current practice, but indicated that the factors recommended by AASHTO may be unconservative for this region.

Calibration of Resistance Factors for Axial Capacity of Driven Pile Into Missouri Soil
Calibration of Resistance Factors for Axial Capacity of Driven Pile Into Missouri Soil

Author: Mulugeta Abay Kebede

Publisher:

Published: 2010

Total Pages: 270

ISBN-13:

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"Over the past two decades the load resistance factor design (LRFD) has been accepted by the American Association for Transportation and Highway Officials (AASHTO) for the design of bridges. This approach is now gaining widespread popularity in the United States for substructure bridge design, including the design of driven pile foundations, as the states calibrate the geotechnical resistance factors for local geological conditions and practices. This study presents the geotechnical resistance factors calibrated for axially driven pile using the first-order reliability method (FORM) for the target reliability index of 2.33 and 3.0 based on 64 end-of-drives (EOD) and 22 beginning-of restrike (BOR) pile driving analyzer (PDA) test data from nine bridge sites in Missouri. Three static pile capacity prediction methods were used, i.e. the Nordlund, Meyerhof and Beta methods. The work investigated the efficiency of each method based on the bias factor, the ratio of the measured to the predicted capacity of the pile, ([lambda] = R[subscript m]/R[subscript p]), the coefficient of variation (COV), and efficiency factor or the ratio of the resistance factor to the bias factor, ([phi]/[lambda]). It verified that the Beta and Nordlund methods provide better predictions than the Meyerhof method. In addition, a comparison of the resistance factor in current AASHTO LRFD with the calibrated resistance factor shows that validating the resistance factors in the AASHTO may result in less reliable design. Finally, the recommended resistance factors for LRFD design are provided for use in Missouri. In addition, further refinement of the developed resistance factors is recommended to improve the resistance factors using large quantity and high quality of data that cover wide areas the glaciated plain and southeast lowland geological regions"--Abstract, leaf iii.

Driven Pile Load Test Data for Load and Resistance Factor Design in Missouri
Driven Pile Load Test Data for Load and Resistance Factor Design in Missouri

Author: Joseph Ronson Cravens

Publisher:

Published: 2011

Total Pages: 332

ISBN-13:

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"The Missouri Department of Transportation (MoDOT) has recently migrated from allowable stress design (ASD) to load and resistance factor design (LRFD) of driven piles. This transition was initiated when the Federal Highway Administration (FHWA) issued a policy stating that all new bridge designs shall be designed in accordance with the American Association of State Highway and Transportation Officials (AASHTO) LRFD Bridge Design Specifications to eliminate the difference in design methodologies for bridge superstructures and bridge substructures. However, the resistance factors for driven piles specified in the AASHTO LRFD specifications are based on nationwide pile data, consisting of a wide range of different geologies, subsurface conditions, and installation procedures. For MoDOT to fully benefit from the transition from ASD to LRFD, resistance factors based on MoDOT's local practices and geologic conditions must be developed. The presented research was dedicated to collecting pile load test data to allow the calibration of resistance factors for ultimate limit state design for predictive methods used by MoDOT to determine pile capacity, as well as to develop related reliability-based quality control criteria of driven pile foundations. MoDOT's current state of practice was evaluated and all available pile load test data was collected. However, MoDOT has records for only 10 pile load tests. Therefore, the search was extended to Missouri's eight neighboring states by distributing questionnaires to surrounding state transportation administrations in hope of gathering pile data. Surrounding states have different geologic conditions, but any collected pile data could be matched to similar soil and rock formations in Missouri's geologic regions. Only five out of eight states responded to the questionnaire, and there was no pile load test data obtained from the states that responded. Therefore, the calibration of resistance factors could not be performed based on the research approaches. The deformation behavior of MoDOT bridge pile foundations was also evaluated at the serviceability limit state by modeling pile foundations in FB-MultiPier. The results indicated that pile displacement is an important factor for the development of serviceability resistance factors for pile foundations. Lastly, recommendations for future MoDOT practice and future research efforts regarding driven piles are provided"--Abstract, leaf iii.

Development of Resistance Factors for Axial Capacity of Driven Piles in North Carolina
Development of Resistance Factors for Axial Capacity of Driven Piles in North Carolina

Author:

Publisher:

Published: 2002

Total Pages:

ISBN-13:

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Resistance factors were developed in the framework of reliability theory for the Load and Resistance Factor Design (LRFD) of driven pile's axial capacity in North Carolina utilizing pile load test data available from the North Carolina Department of Transportation. A total of 140 Pile Driving Analyzer (PDA) data and 35 static load test data were compiled and grouped into different design categories based on four pile types and two geologic regions. Resistance statistics were evaluated for each design category in terms of bias factors. Bayesian updating was employed to improve the statistics of the resistance bias factors, which were derived from a limited number of pile load test data. Load statistics presented in the current AASHTO LRFD Bridge Design Specifications were used in the reliability analysis and the calibration of the resistance factors. Reliability analysis of the current NCDOT practice of pile foundation design was performed to evaluate the level of safety and to select the target reliability indices. Resistance factor calibration was performed for the three methods of static pile capacity analysis commonly used in the NCDOT: the Vesic, the Nordlund, and the Meyerhof methods. Two types of First Order Reliability Methods (Mean Value First Order Second Moment method and Advanced First Order Second Moment method) were employed for the reliability analysis and the calibration of the resistance factors. Recommended resistance factors are presented for the three methods of static pile capacity analysis and for seven different design categories of pile types and geologic regions. The resistance factors developed and recommended from this research are specific for the pile foundation design by the three static capacity analysis methods and for the distinct soil type of the geologic regions of North Carolina. The methodology of the resistance factor calibration developed from this research can be applied to the resistance factor calibration for other foundation.

Development of LRFD Design Procedures for Bridge Piles in Iowa
Development of LRFD Design Procedures for Bridge Piles in Iowa

Author:

Publisher:

Published: 2012

Total Pages:

ISBN-13:

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For well over 100 years, the Working Stress Design (WSD) approach has been the traditional basis for geotechnical design with regard to settlements or failure conditions. However, considerable effort has been put forth over the past couple of decades in relation to the adoption of the Load and Resistance Factor Design (LRFD) approach into geotechnical design. With the goal of producing engineered designs with consistent levels of reliability, the Federal Highway Administration (FHWA) issued a policy memorandum on June 28, 2000, requiring all new bridges initiated after October 1, 2007, to be designed according to the LRFD approach. Likewise, regionally calibrated LRFD resistance factors were permitted by the American Association of State Highway and Transportation Officials (AASHTO) to improve the economy of bridge foundation elements. Thus, projects TR-573, TR-583 and TR-584 were undertaken by a research team at Iowa State University's Bridge Engineering Center with the goal of developing resistance factors for pile design using available pile static load test data. To accomplish this goal, the available data were first analyzed for reliability and then placed in a newly designed relational database management system termed PIle LOad Tests (PILOT), to which this first volume of the final report for project TR-573 is dedicated. PILOT is an amalgamated, electronic source of information consisting of both static and dynamic data for pile load tests conducted in the State of Iowa. The database, which includes historical data on pile load tests dating back to 1966, is intended for use in the establishment of LRFD resistance factors for design and construction control of driven pile foundations in Iowa. Although a considerable amount of geotechnical and pile load test data is available in literature as well as in various State Department of Transportation files, PILOT is one of the first regional databases to be exclusively used in the development of LRFD resistance factors for the design and construction control of driven pile foundations. Currently providing an electronically organized assimilation of geotechnical and pile load test data for 274 piles of various types (e.g., steel H-shaped, timber, pipe, Monotube, and concrete), PILOT (http://srg.cce.iastate.edu/lrfd/) is on par with such familiar national databases used in the calibration of LRFD resistance factors for pile foundations as the FHWA's Deep Foundation Load Test Database. By narrowing geographical boundaries while maintaining a high number of pile load tests, PILOT exemplifies a model for effective regional LRFD calibration procedures.

Load and Resistance Factor Design (LRFD) Pile Driving Project - Phase II Study
Load and Resistance Factor Design (LRFD) Pile Driving Project - Phase II Study

Author: Aaron S. Budge

Publisher:

Published: 2014

Total Pages: 514

ISBN-13:

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Driven piles are the most common foundation solution used in bridge construction (Paikowsky et al., 2004). Their safe use requires to reliable verification of their capacity and integrity. Dynamic analyses of driven piles are methods attempting to obtain the static capacity of a pile, utilizing its behavior during driving. Dynamic equations (aka pile driving formulas) are the earliest and simplest forms of dynamic analyses. The development and the examination of such equation tailored for MnDOT demands is presented. In phase I of the study reported by Paikowsky et al. (2009, databases were utilized to investigate previous MnDOT (and other) dynamic formulas and use object oriented programming for linear regression to develop a new formula that was then calibrated for LRFD methodology and evaluated for its performance. This report presents the findings of phase II of the study in which a comprehensive investigation of the Phase I findings were conducted. The studies lead to the development of dynamic formulae suitable for MnDOT foundation practices, its calibrated resistance factors and its application to concrete and timber piles. Phase II of the study also expanded on related issues associated with Wave Equation analyses and static load tests, assisting the MnDOT in establishing requirements and specifications.