Incorporating setup into load and resistance factor design of driven piles in sand

2009 ◽  
Vol 46 (3) ◽  
pp. 296-305 ◽  
Author(s):  
Luo Yang ◽  
Robert Liang
Keyword(s):  
Design Procedure ◽  
Resistance Factor ◽  
Driven Piles ◽  
Pile Setup ◽  
Economical Design ◽  
Reliability Method ◽  
Long Time ◽  
Factor Design ◽  
Total Capacity ◽  
Load And Resistance Factor

A comprehensive database is developed for the setup for piles driven into sand. Based on the compiled pile-testing data, pile setup is significant and continues to develop for a long time after pile installation. The statistical analysis shows that a logarithm-normal distribution can be used to describe the probabilistic characteristics of the predicted setup capacity using the Skov and Denver equation. The main objective of this paper is to incorporate the setup effect into a reliability-based load and resistance factor design (LRFD) of driven piles in sand. The first-order reliability method (FORM) is used to derive separate resistance factors that would account for different degrees of uncertainties associated with measured short-term capacity and predicted setup capacity. The incorporation of setup effects in the LRFD helps improve the prediction of total capacity of driven piles, resulting in more economical design. A practical design procedure within the LRFD framework to incorporate the pile setup effects is outlined.

Incorporating set-up into reliability-based design of driven piles in clay

2006 ◽  
Vol 43 (9) ◽  
pp. 946-955 ◽  
Author(s):  
Luo Yang ◽  
Robert Liang
Keyword(s):  
Resistance Factor ◽  
Driven Piles ◽  
Statistical Parameters ◽  
First Order Reliability Method ◽  
First Order ◽  
Axial Capacity ◽  
Reliability Method ◽  
Factor Design ◽  
Set Up ◽  
Load And Resistance Factor

A statistical database is developed to describe the increase in pile axial capacity with time, known as set-up, when piles are driven into clay. Based on the collected pile testing data, pile set-up is significant and continues to develop for a long time after pile installation. The statistical database shows that normal distribution can be used to properly describe the probabilistic characteristics of predicted set-up capacity by the Skov and Denver equation. The main objective of this paper is to incorporate the set-up effect into a reliability-based load and resistance factor design (LRFD) of driven piles. The statistical parameters for set-up effect combined with the previously documented statistics of load and resistance can be systematically accounted for in the framework of reliability-based analysis using the first-order reliability method (FORM). Separate resistance factors are obtained to account for different degrees of uncertainties associated with measured short-term capacity and predicted set-up capacity at various reliability levels. The incorporation of set-up effect in LRFD can improve the prediction of design capacity of driven piles. Thus, pile length or numbers of pile could be reduced and economical design of driven piles could be achieved.Key words: driven piles, set-up, reliability, load and resistance factor design (LRFD), first-order reliability method (FORM).

Load and Resistance Factor Design (LRFD) for Driven Piles Using Dynamic Methods—A Florida Perspective

2000 ◽  
Vol 23 (1) ◽  
pp. 55 ◽  
Author(s):  
RC Chaney ◽  
KR Demars ◽  
MC McVay ◽  
B Birgisson ◽  
L Zhang ◽  
...  
Keyword(s):  
Resistance Factor ◽  
Driven Piles ◽  
Dynamic Methods ◽  
Factor Design ◽  
Load And Resistance Factor

Risk-Informed Load and Resistance Factor Design (LRFD) Methods for Piping

2005 ◽  
Author(s):  
Bilal M. Ayyub ◽  
Ibrahim A. Assakkaf ◽  
Klieo Avrithi ◽  
Abinav Gupta ◽  
Nitin Shah ◽  
...  
Keyword(s):  
Resistance Factor ◽  
Future Research ◽  
Performance Requirements ◽  
Reliability Method ◽  
Load Effects ◽  
Partial Safety Factors ◽  
Factor Design ◽  
And Performance ◽  
Load And Resistance Factor ◽  
Technical Basis

The main objective of structural design is to insure safety, functional, and performance requirements of a structural system for selected target reliability levels, for specified period of time and for a specified environment. As this must be accomplished under conditions of uncertainty, risk and reliability analyses are deemed necessary in the development of such methods as risk-informed load and resistance factor design for piping. This paper provides a summary of the methodology and technical basis for reliability-based, load and resistance factor design suitable for the ASME Section III, Class 2/3 piping for primary loading, i.e., pressure, deadweight and seismic. The methodology includes analytical procedures, such as the First-Order Reliability Method (FORM) for calculating the LRFD-based partial safety factors for piping. These factors were developed in this paper for demonstration purposes, and they can be used ultimately in LRFD design formats to account for the uncertainties in strength and in the load effects. The technical basis provided in the paper is suitable for a proof-of-concept in that LRFD can be used in the design of piping with consistent reliability levels. Also, the results from additional projects in this area, including future research for piping secondary loads, will form the basis for future code cases.

Resistance Factors for Single Driven Piles from Experiments

1997 ◽  
Vol 1569 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Gil L. Yoon ◽  
Michael W. O’Neill
Keyword(s):  
Sampling Technique ◽  
Load Factor ◽  
Driven Piles ◽  
Resistance Factors ◽  
Present Generation ◽  
Reliability Method ◽  
First Order Second Moment ◽  
Factor Design ◽  
Load And Resistance Factor ◽  
A Site

Present-generation resistance factors for foundations in load and resistance factor design (LRFD) do not necessarily reflect directly the variance in site-specific resistance and bias in making resistance estimates. The purpose of this paper is to describe a process whereby resistance factors can be determined from experimental data at a site and to demonstrate that process for driven piles at a specific site in overconsolidated clay. Eleven pipe piles were tested to failure in compression, and 28 cone penetrometer tests (CPTs) were performed near the piles. The CPT results were characterized through both a geostatistical method and a random sampling technique to estimate resistance factors for ultimate pile resistances using three CPT methods and two α-methods. A first-order, second-moment reliability method was applied using the interpreted bias characteristics of the design methods and the dispersion characteristics of the CPT and pile tests to relate resistance factors to selected reliability indexes. The resistance factors obtained for this site by this process were 0.50 to 0.62 for the three CPT methods and 0.30 to 0.55 for the ॅ-methods for a target reliability index of 3.5, depending on the value selected for the live load factor.

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