TY - JOUR

T1 - Calibration of resistance factor for design of pile foundations considering feasibility robustness

AU - Li, Dian Qing

AU - Peng, Xing

AU - Khoshnevisan, Sara

AU - Juang, C. Hsein

N1 - Publisher Copyright:
© 2016 Elsevier Ltd

PY - 2017/1/1

Y1 - 2017/1/1

N2 - The resistance factor for pile foundations in load and resistance factor design (LRFD) is traditionally calibrated considering target reliability index (βT) and statistics of load and resistance bias factors. However, the resistance bias factor is hard to quantify statistically. Consequently, the design obtained using the calibrated resistance factor can still miss βT if the variation in resistance bias factor has been underestimated. In this paper, we propose a new resistance factor calibration approach to address this dilemma by considering “feasibility robustness” of design in the calibration process. Herein, the feasibility robustness is defined as a probability that the βT requirement can still be satisfied even in the presence of uncertainty or variation in the computed bearing capacity. For illustration, LRFD approach for pile foundations commonly used in Shanghai, China is examined. Emphasis is placed on re-calibration of resistance factors at various feasibility robustness levels, with due consideration of the variation in the resistance bias factor. A case study is presented to illustrate the use of the re-calibrated resistance factors. The results show that the feasibility robustness is gained at the expense of cost efficiency; in other words, the two objectives are conflicting. To aid in the design decision-making, an optimal feasibility robustness level and corresponding resistance factors are suggested in the absence of a designer's preference.

AB - The resistance factor for pile foundations in load and resistance factor design (LRFD) is traditionally calibrated considering target reliability index (βT) and statistics of load and resistance bias factors. However, the resistance bias factor is hard to quantify statistically. Consequently, the design obtained using the calibrated resistance factor can still miss βT if the variation in resistance bias factor has been underestimated. In this paper, we propose a new resistance factor calibration approach to address this dilemma by considering “feasibility robustness” of design in the calibration process. Herein, the feasibility robustness is defined as a probability that the βT requirement can still be satisfied even in the presence of uncertainty or variation in the computed bearing capacity. For illustration, LRFD approach for pile foundations commonly used in Shanghai, China is examined. Emphasis is placed on re-calibration of resistance factors at various feasibility robustness levels, with due consideration of the variation in the resistance bias factor. A case study is presented to illustrate the use of the re-calibrated resistance factors. The results show that the feasibility robustness is gained at the expense of cost efficiency; in other words, the two objectives are conflicting. To aid in the design decision-making, an optimal feasibility robustness level and corresponding resistance factors are suggested in the absence of a designer's preference.

KW - Calibration

KW - Feasibility robustness

KW - Load and resistance factor design

KW - Pile foundations

KW - Target reliability index

KW - Uncertainty

UR - http://www.scopus.com/inward/record.url?scp=84984601444&partnerID=8YFLogxK

U2 - 10.1016/j.compgeo.2016.08.018

DO - 10.1016/j.compgeo.2016.08.018

M3 - 期刊論文

AN - SCOPUS:84984601444

SN - 0266-352X

VL - 81

SP - 229

EP - 238

JO - Computers and Geotechnics

JF - Computers and Geotechnics

ER -