Calibration of Load and Resistance Factors for Reinforced Concrete

Abstract

Current approach for designing of reinforced concrete members is based on the load and resistance factor. However the load and resistance parameters are random variables, the constant values have been designated for them in the designing procedure. Assuming these factors as the constants, will be led to the unsafe and uneconomical designs. Safe designing of structures requires appropriate recognition of the effective parameters and their uncertainties. Therefore, this achievement is possible through clarifying the effective design parameters and applying risk-based design methods. The main purpose of this paper is reliability based design of the reinforcement concrete structures under bending action. Rectangular sections with tension rebars (singly reinforced), rectangular sections with tension and also compression rebars (doubly reinforced) and T-shape sections are designed based on probabilistic methods. The appropriate tool for reliability calculations is selected based on pros and cons of each method. Evaluation of the load and the resistance factors for all mentioned beams is the next goal of this investigation. In this research, the steel usages for desired safety level are determined through the produced graphs. Using the proposed methodologies, the economic and fully probabilistic design of the concrete beams for bending is now available.