Considerations for Resistance Factor Calibration in the National Building Code of Canada

ABSTRACT: The Canadian Highway Bridge Design Code (CHBDC), CAN/CSA-S6-14, adopted a resistance and consequence factor design approach in their 2014 edition. The resistance and consequence factors were calibrated for the CHBDC using probabilistic models capturing the Load and Resistance Factor Design (LRFD) framework. The National Building Code of Canada (NBCC) is beginning to develop its own geotechnical LRFD framework. However, the resistance and consequence factors have yet to be calibrated specifically for the NBCC. The NBCC differs from the CHBDC in at least three areas which are important to this calibration process: 1) The load factors and load combinations used in the NBCC are different than those used in the CHBDC, 2) The design life in the NBCC is 50 years and 75 years in the CHBDC, 3) The target reliability index in the NBCC is 3.0 over a 50-year design life, while the CHBDC specifies an annual reliability index of 3.75. The changes in these factors will affect the resistance and consequence factors required to achieve the specified reliability. This paper presents the results of a preliminary calibration of resistance factors for the NBCC.