Formulas: Design for Strength Using Load and Resistance Factor Design (LRFD)

Equation C-B3-1

The probability that $R$ is less than $Q$ depends on the distributions of the many variables (material, loads, etc.) that determine resistance and total load effect. Often, only the means and the standard deviations or coefficients of variation of the variables involved in the determination of $R$ and $Q$ can be estimated. However, this information is sufficient to build an approximate design provision that is independent of the knowledge of these distributions, by stipulating the following design condition:

where

$\begin{aligned} R_{m} & =\text { mean value of the resistance, } R \\ Q_{m} & =\text { mean value of the load effect, } Q\end{aligned}$

Equation C-B3-2

Found in

• DESIGN BASIS