The probability obtained through a structural reliability analysis cannot be observed in the real world and, therefore, should not be interpreted in an absolute sense.
In a fully probabilistic design approach, the system design is selected such that it meets a target reliability requirement, while modeling uncertainties are explicitly taken into account.
FORM is a structural reliability analysis method that approximates the probability of failure by linearizing the limit state function around the design point.
The uncertain model parameters are transformed into independent standard Normal random variables. For the performance and stability of numerical algorithms, performing such a transformation step is sometimes preferable.
It is the point in the failure domain that has the smallest distance to the origin in standard Normal space. This point is also referred to as design point.
