7 th Lecture: Probabilistic Modelling in Structural Engineering
Aim of the present lecture
The aim of the present lecture is to present models used in probabilistic structural engineering
for the modelling of loads, resistances and model uncertainties. For each of these types of
variables first some general comments are given and thereafter simplified versions of the
probabilistic models from the Probabilistic Model Code of the Joint Committee on Structural
Safety are provided. The probabilistic load models address individual loads as well as the
important load combination problem. The most usual load and resistance parameters are
addressed and thereby the presented material should facilitate the probabilistic modelling of
the most frequently occurring structural reliability problems. The introduced models, in
conjunction with the methods of structural reliability introduced in Lecture 6, provide a first
starting point for the assessment of the reliability of structures for the purpose of design. On
the basis of the present lecture, it is expected that the students should acquire knowledge and
skills in regard to:
Which are the characteristics of loads to consider in the probabilistic modelling?
What is an equivalent uniformly distributed load?
Which distribution function can be used for the modelling of dead loads and which can be
used for the modelling of variable loads?
How may loads be combined for the assessment of their maximum in a given reference
period?
Which are the characteristics of materials that must be considered when modelling the
resistance of materials?
In what way do geometrical uncertainties play a role for the modelling of resistances?
In what way can physical considerations provide aid in the selection of probabilistic
models for loads and resistances?