Title:
Calibration of Design Code for Buildings (ACI 318): Part 2—Reliability Analysis and Resistance Factors
Author(s):
Maria M. Szerszen and Andrzej S. Nowak
Publication:
Structural Journal
Volume:
100
Issue:
3
Appears on pages(s):
383-391
Keywords:
analysis; load; resistance
DOI:
10.14359/12614
Date:
5/1/2003
Abstract:
Calibration of the design code for concrete structures is presented in two studies. The first one focused on the development of resistance models. This paper deals with the reliability analysis and selection of resistance factors. The structural types considered in this study include beams, structural slabs, and columns. The analysis is performed for reinforced concrete and prestressed concrete elements. A wide range of materials is covered: ordinary concrete, high-strength concrete, lightweight concrete, reinforcing bars No. 3 through 11, and two grades of prestressing strands. The reliability analysis requires the knowledge of the statistical parameters for load and resistance. Resistance models are described in the first paper. In addition to the material parameters based on the new test results, the parameters used in previous studies (1970s) were considered. Load models are based on the data available in literature. Reliability indexes are calculated using various load combinations, the basic combination of dead load and live load, and other combinations with snow, wind, and earthquake for the two resistance models considered (older database and new material database). The resulting values of the reliability index calculated for the old data base and old load models, and potential consequences of failure, served as a basis for the selection of the target reliability index. For each type of structural element and load combination case, several possible values of the resistance factor were considered (rounded to the nearest 0.05). The recommended values provide a close fit to the target reliability levels.