72785 - Structural Safety

Academic Year 2023/2024

  • Moduli: Tomaso Trombetti (Modulo 1) Vittoria Laghi (Modulo 2)
  • Teaching Mode: Traditional lectures (Modulo 1) Traditional lectures (Modulo 2)
  • Campus: Bologna
  • Corso: Second cycle degree programme (LM) in Civil Engineering (cod. 8895)

    Also valid for Second cycle degree programme (LM) in Civil Engineering (cod. 0930)

Learning outcomes

The method for safety evaluation and risk assessment of civil structures will be studied. Definition of loadings and structural safety will be given in a probabilistic framework. Risk assessment of civil structures in earthquake regions will be analyzed with details.

Course contents

Requirements/Prior knowledge

A prior knowledge and understanding of structural behaviour is required to attend with profit this course.

In addition, students should master the basics of mathematical analysis.

Fluent spoken and written English is a necessary pre-requisite: all lectures, tutorials and study material will held be in English.


Course contents

The student will be acquainted with the different methods for evaluation of the safety and risk associated with civil structures and their design.

The objective of these methods being the evaluation of the probability of violation of a limit state function (such as collapse).

The failure probability will be obtained from the various sources of uncertainty/randomness associated with: loadings, material properties, structural geometry, boundary conditions, as well as structural models and analysis techniques.

The course will also cover example of structurally sound systems as well of major structural collapse/failures both with reference to static and seismic loadings. The reasons behind the selection of the safety factors used in common Codes will also be covered.


MODULE 1: Structural reliability analysis

Specific knowledge on structural reliability theory will be provided to students.

Basic probability theory will be studied to assess the risk associated to simple structural systems.

The module will cover the following topics:

. Review of probability theory.

· Structural Component reliability analysis.

· Analysis of uncertainties - Bayesian Reliability analysis.

. Random variables

. Function of random variables

. different types of random variable distribution

. Gaussian and Standard Normal distribution

. Fundamental concept of structural reliability (G Function)

. FORM and SORM reliability methods

· Probabilistic codified Design.


MODULE 2: Conceptual structural design

Basic concepts of structural design, form finding and structural functioning will be provided. Examples from the past will be studied to learn conceptual structural design principles.

The module will cover the following topics:

· Review of conceptual design.

· Simulation methods.

· Examples of "Robust" structural design.

· Examples of structural failures.

. The role of conceptual design in structural reliability.


Recommended text:

Armen Der Kiureghian, "Structural and System Reliability", Cambridge University Press, 2022.

Melchers. "Structural Reliability Analysis and Prediction" , Second Editio. John Wiley, 1999.


Augusti, Baratta, Casciati. "Probabilistic Methods in Structural Engineering". Prentice Hall, 1984.

Ang, Tang. "Probabilistic Concepts in engineering planning and design". Vol I. Chapman Hall, 1975.

Ang, Tang. "Probabilistic Concepts in engineering planning and design". Vol II. Chapman Hall, 1984.

Benjamin, Cornell. "Probability, Statistics and Decision for Civil Engineers" McGraw Hill, 1970.

Teaching methods

Planned learning activities and teaching methods

The course takes part of the innovative teaching project sponsored by University of Bologna ("progetto di innovazione didattica di Ateneo").

Module 1: Frontal teaching classes, both at the blackboard and with the use of power point slides.

Module 2: Online teaching classes with the support of virtual sources.

Assessment methods

Achievements will be assessed by the means of a final exam. This is based on an analytical assessment of the "expected learning outcomes" described above.

In order to properly assess such achievement the examination is composed of three different sections: all of them are oral.

The verification of the knowledge attained by the student will be developed through a final exam aimed at verifying: knowledges, abilities and critical capabilities acquired and developed by the student in the course.



The final exam is composed in two parts to be taken on the same day:

1) In the first part the student is asked to illustrate the solutions developed with reference to series of take home exercises that the professor is handing out a week before the exam.

2) In the second part the student is required to provide oral answers to theoretical questions based upon the mathematical theory of probability illustrated in class.

To obtain a passing grade, students are required to at least demonstrate a knowledge of the key concepts of the of mathematical theory of probability (as well as its relationship with structural safety and its application to actual structural engineering), some ability for critical application, and a comprehensive use of technical language.

Higher grades will be awarded to students who demonstrate an organic understanding of the subject, a high ability for critical application, and a clear and concise presentation of the contents. In detail a higher grade will be given to students who will show to have both a good knowledge of the mathematical theory of probability and a good critical understanding of structural behaviour and its relation to structural safety (as illustrated throughout the course with case studies)

A failing grade will be awarded if the student shows knowledge gaps in key-concepts of the subject, inappropriate use of language, and/or logic failures in the analysis of the subject of structural safety and reliability.



The final exam is composed of an oral presentation regarding a real-case example of a structural system. Examples include, but are not limited to:

- great examples of failures of structural systems

- detailed study of the conceptual design of a famous building / infrastructure

- re-thinking of a design concept through the development of a new structural system

To obtain a passing grade, students are required to demonstrate a knowledge on the conceptual structural design theories and implications in the structural reliability.

Higher grades will be awarded to students who add detailed information on their project, with the help of additional material (such as detailed printed report) and resources.

Teaching tools

Handouts, development of applicative examples, power point presentations, applicative software.

Office hours

See the website of Tomaso Trombetti

See the website of Vittoria Laghi