# STRUCTURAL SAFETY AND RELIABILITY - 2018/9

Module code: ENGM050

Module Overview

Risk-based decision making is increasingly being pursued in a wide range of civil engineering projects, whether it concerns the safety level associated with a new high-rise building or the residual safety in an existing bridge. The module aims to provide grounding in the development, application and use of risk-based methods in civil engineering, particularly in problems related to structural engineering. Basic probability and statistics tools are first reviewed, and then applied to reliability problems related to structural response of simple systems. The link between structural reliability and limit state design philosophy is established and quantified. The formulation and use of such quantitative methods in more complex and realistic situations is presented, drawing from a wide range of both practical and research problems.

Module provider

Civil and Environmental Engineering

CHRYSSANTHOPOULOS M Prof (Civl Env Eng)

Number of Credits: 15

ECTS Credits: 7.5

Framework: FHEQ Level 7

JACs code: H210

Module cap (Maximum number of students): N/A

Module Availability

Semester 2

Prerequisites / Co-requisites

Knowledge of relevant mathematical and statistical concepts, normally taught at FHEQ levels 4 or 5 of engineering programmes; Knowledge of structural analysis and design at FHEQ level 6, as applied to new and ageing structures, and the factors affecting their response, acquired through undergraduate study and/or professional experience in civil engineering.

Module content

Revision of Probability and Statistics: Probability theory, Random Variables, The Normal Distribution, Other Common Distributions, Moments and Parameter Estimation, Correlation and Joint Distributions.

Structural Reliability Theory: The R-S problem in structural design and assessment, Probability of Failure and the Reliability Index.

Structural Reliability Methods: Convolution Integral, Standardised Method for Normal Variables, First Order Reliability Method, Monte Carlo Simulation.

System Reliability Concepts: Series and Parallel Systems, Mixed Systems, Methods of estimating System Failure Probability, Introduction to System Bounds

Introduction to Risk: Causes of structural failure, ALARP, the Product-Process-People approach to risk management

Reliability-based Codes: Specification of Characteristic Load/Resistance Values, Design Values, Partial Factors, Target Reliability, Methods of Code Calibration.

Reliability-based Design: The use of ISO 2394 method and its significance.

Areas of applications in design optimisation, assessment, inspection and maintenance optimisation, and whole life planning for individual or stocks of structures; examples of applications on different types of structures such as offshore structures and bridges.

Assessment pattern

Assessment type Unit of assessment Weighting
Coursework COURSEWORK 25
Examination EXAM 2 HOURS 75

Alternative Assessment

None.

Assessment Strategy

The assessment strategy is designed to provide students with the opportunity to demonstrate:

Knowledge and understanding of the use of probabilistic concepts and methods in applications related to structural design and assessment
Ability to obtain failure probability estimates through the use of an appropriate structural reliability method
Ability to interpret critically the results of a reliability analysis and their implications in designing structural elements
Knowledge and understanding of the principles and methods employed in modern codes of practice, particularly in the specification of characteristic and design values for load and resistance variables
Ability to identify the steps and important factors in risk management tasks.

Thus, the summative assessment for this module consists of:

Examination [Learning outcomes assessed 1 to 7] {75%}
Coursework assignments [Learning outcomes 3, 4, 5 and 7] {25%}

Assignment 1: Concepts of Probability and Statistics applied to Civil/Structural Engineering problems (10 hours, 10%)

Assignment 2: Application of Structural Reliability methods (20 hours, 15%)

Formative assessment and feedback is through a range of self-assessment exercises, which are tackled also in tutorial sessions. Worked solutions are provided after the students have had a chance to address these in their own time and at tutorial sessions. Feedback is also given through comments on coursework submissions.

Module aims

• Provide an appreciation of the various uncertainties associated with civil engineering works and the use of risk and reliability methods to assess and manage risk in the life of a structure.
• Describe a range of alternative techniques for estimating the probability of failure associated with various limit states in structures.
• Develop a thorough understanding of the use of probabilistic methods in specifying load and resistance values in codes of practice.
• Provide the analytical tools with which the specification and calibration of partial safety factors is undertaken in codes of practice.
• Develop the ability to obtain quantitative estimates of the reliability of structures under different limit state conditions
• Promote an appreciation of the wide spectrum of applications in this area and potential benefits from the use of these techniques in the design and assessment of major structures.

Learning outcomes

Attributes Developed
001 Describe the sources of uncertainty in variables encountered in structural design and assessment and explain their significance in structural safety and reliability K
002 Identify and categorise the principal risks associated with the design, construction and operation of major structures KCPT
003 Evaluate the probability of failure of structural elements and simple structural systems KCT
004 Perform reliability-based limit state design of simple structural elements and recognise the sensitivity of the outcome to the uncertainty in different variables KCT
005 Explain the reasons leading to different values of partial safety factors for load and resistance variables in design and assessment standards KCT
006 Interpret reliability analysis results pertaining to complex structural systems, typically undertaken through commercially available software packages KCPT
007 Identify the limitations of quantitative reliability methods in relation to life-cycle risk management of structures KCPT
008 Technical report writing T
009 Oral & written communication T
010 Graphical presentation of data T
011 Sketching T
012 3D spatial awareness T
013 Critical thinking T
014 Observation T

Attributes Developed

C - Cognitive/analytical

K - Subject knowledge

T - Transferable skills

P - Professional/Practical skills

Independent Study Hours: 117

Lecture Hours: 24

Tutorial Hours: 9

Methods of Teaching / Learning

The learning and teaching strategy is designed to present and explain the principles, conventions and operational methods employed by modern codes of practice based on the limit state design philosophy, building on a foundation related to probability theory and structural reliability methods. The knowledge gained, together with analytical/cognitive skills developed, in this module will allow the students to use design codes and assessment standards with a greater degree of confidence and a deeper understanding of clauses and specifications. The students will also be suitably prepared to appreciate changes that may be introduced in codes and standards, due to improved models or more complete information becoming available during the course of their professional career. Finally, they will be able to identify and critically review situations where reliability targets need to reflect particular project objectives.

The module is delivered principally by lectures but also includes tutorial/question classes where, for each topic, progressively more challenging problems are being tackled. Both lectures and tutorials are scheduled within a three hour session per week, with a typical ratio of 2:1, for 11 weeks. The learning and teaching methods include:

Lectures on Probability and Statistics Concepts (7 hours)
Tutorials on probability and statistics (2 hours)
Lectures on Structural Reliability Theory (6 hours)
Lectures on Structural Reliability Methods (6 hours)
Tutorials on structural reliability (3 hours)
Lectures on Risk and Reliability in Codes and Standards (5 hours)
Tutorial on reliability and codified design (1 hour)
Revision session (3 hours)
Coursework assignment on probability and statistics concepts (10 hours)
Coursework assignment on reliability methods (20 hours)
Directed and guided reading, including revision( 85 hours)
Exam (2 Hours)

Indicated Lecture Hours (which may also include seminars, tutorials, workshops and other contact time) are approximate and may include in-class tests where one or more of these are an assessment on the module. In-class tests are scheduled/organised separately to taught content and will be published on to student personal timetables, where they apply to taken modules, as soon as they are finalised by central administration. This will usually be after the initial publication of the teaching timetable for the relevant semester.

Reading list for STRUCTURAL SAFETY AND RELIABILITY : http://aspire.surrey.ac.uk/modules/engm050

Programmes this module appears in

Programme Semester Classification Qualifying conditions
Structural Engineering MSc 2 Optional A weighted aggregate mark of 50% is required to pass the module
Civil Engineering MSc 2 Optional A weighted aggregate mark of 50% is required to pass the module
Bridge Engineering MSc 2 Optional A weighted aggregate mark of 50% is required to pass the module
Infrastructure Engineering and Management MSc 2 Optional A weighted aggregate mark of 50% is required to pass the module
Advanced Geotechnical Engineering MSc 2 Optional A weighted aggregate mark of 50% is required to pass the module
Civil Engineering MEng 2 Optional A weighted aggregate mark of 50% is required to pass the module

Please note that the information detailed within this record is accurate at the time of publishing and may be subject to change. This record contains information for the most up to date version of the programme / module for the 2018/9 academic year.