# Structural Reliability

By Prof. Baidurya Bhattacharya   |   IIT Kharagpur
Learners enrolled: 295
The civil engineering community, and structural engineers in particular, have long recognized the important role played by variability and incomplete information in their profession: (i) random system properties, (ii) unpredictable future loads and strength deterioration, (iii) human errors, and (iv) imperfect mathematical models. Ensuring adequate safety and reliability for all stakeholders in the presence of these uncertainties is therefore a central objective of design analysis and assessment of structural systems. This course aims to give the students the ability to model uncertainties and manage risks in civil engineering activities in a way that best serves the interests of society.

INTENDED AUDIENCE : 4th year advanced UG students, 1st year MTech, 1st year PhD students

PRE REQUISITE : Must have completed at least 2nd year UG curriculum in engineering with course(s) in Engineering Mechanics Must have taken courses in probability & statistics, linear algebra and basic calculus

SUPPORTED INDUSTRIES : All companies with R&D facilities, all national labs including DAE, ISRO, DRDO labs
Summary
 Course Status : Upcoming Course Type : Elective Duration : 12 weeks Start Date : 26 Jul 2021 End Date : 15 Oct 2021 Exam Date : 23 Oct 2021 Enrollment Ends : 02 Aug 2021 Category : Civil Engineering Credit Points : 3 Level : Postgraduate

### Course layout

Part A: Basics
Week 1: Pre-requisites. Introduction and overview.
Review of basic probability. Random variables, probability laws, common probability distributions – origins and interrelations.
Simple one variable example problems.
Week 2: Random variables
Functions of random variables.
Joint probability distributions, conditional distributions. Joint Normal distribution. Concepts of point process. Simple one- and multi- variable example problems
Week 3: Monte Carlo simulations
Introduction to Monte Carlo simulations. Generation of samples from various discrete and continuous distributions, generation of dependent samples
Variance reduction techniques. Examples: simple coding problems

Part B: Fundamentals of Reliability
Week 4: Basic definitions
Reliability – historical development, applications, different measures of reliability. Component vs. system reliability.
Probabilistic formulation of civil engineering problems. Concepts of performance requirements and definitions of failure.
Week 5: Systems reliability
General formulation of system reliability problems - representation of failure, series and parallel systems, redundancy, fault trees, cut sets.
How structural systems are different.
Week 6: Time to failure
Time to failure based formulation of reliability problems – components and systems. Reliability and hazard functions. Poisson processes.

Part C: Reliability of Structures
Week 7: Capacity-demand-time
Capacity-demand-time (“physics based”) formulation for structural components: limit states. Closed form solutions of simple limit state probabilities. Concept of first passage problem.
Week 8: Approximate solutions
Approximate solutions to component reliability problems: FORM, SORM, MCS Examples: Solution of benchmark problems
Week 9: Structural systems reliability
Formulation of and approximate solutions to structural system reliability problems.
System reliability bounds
Week 10: Maintenance
Reliability-based maintenance. Perfect and imperfect repair – effect on reliability and hazard functions.

Part D: Reliability based Design
Week 11: Design codes
Probability-based design and design codes – partial factors of safety. Examples.
Week 12: Reliability & society
Determination of target reliabilities. Concepts of robustness and resilience.

### Books and references

•  Probability and Statistics for Engineering, Hines et al. , Wiley, 2008 (ISBN 9788126516469)
• Probability Concepts in Engineering, A. H-S Ang and W. H. Tang, Wiley, 2006 (ISBN: 978-0-471-72064-5)
• Structural Reliability Analysis and Prediction, RE Melchers and AT Beck, Wiley 2018 (ISBN 9781119266105)

### Prof. Baidurya Bhattacharya

IIT Kharagpur
Professor Bhattacharya works in the area of probabilistic mechanics and computational materials science. His research has involved material degradation, load modelling, damage detection, system identification, seismic reliability analysis and design guides for various structures including nuclear power plant shells, ships, offshore vessels and bridges. He has set up the Structural Reliability Research Facility at IIT Kharagpur. Bhattacharya obtained his BTech in Civil Engineering (1991) from IIT Kharagpur and his MS (1994) and PhD (1997) in Civil Engineering from Johns Hopkins University. He joined the faculty of Civil Engineering at IIT Kharagpur in 2006. He is currently Professor (HAG) and the convener of IIT Kharagpur’s Joint Program Committee with IGCAR on safety analysis of sodium cooled nuclear reactors. He has served the Institute as Chairman Civil Construction and Maintenance. Bhattacharya has been a visiting faculty at Stanford and Johns Hopkins and has served on the faculty of the University of Delaware. He has been a speaker at the Frontiers of Engineering series at the US National Academy of Engineering. He served as an associate editor of ASCE’s Journal of Bridge Engineering for 8 years. He was elected Fellow of the Indian National Academy of Engineering in 2016 and Fellow of the American Society of Civil Engineers in 2018.

### Course certificate

The course is free to enroll and learn from. But if you want a certificate, you have to register and write the proctored exam conducted by us in person at any of the designated exam centres.
The exam is optional for a fee of Rs 1000/- (Rupees one thousand only).
Date and Time of Exams: 23 October 2021 Morning session 9am to 12 noon; Afternoon Session 2pm to 5pm.
Registration url: Announcements will be made when the registration form is open for registrations.
The online registration form has to be filled and the certification exam fee needs to be paid. More details will be made available when the exam registration form is published. If there are any changes, it will be mentioned then.
Please check the form for more details on the cities where the exams will be held, the conditions you agree to when you fill the form etc.

CRITERIA TO GET A CERTIFICATE

Average assignment score = 25% of average of best 8 assignments out of the total 12 assignments given in the course.
Exam score = 75% of the proctored certification exam score out of 100

Final score = Average assignment score + Exam score

YOU WILL BE ELIGIBLE FOR A CERTIFICATE ONLY IF AVERAGE ASSIGNMENT SCORE >=10/25 AND EXAM SCORE >= 30/75. If one of the 2 criteria is not met, you will not get the certificate even if the Final score >= 40/100.

Certificate will have your name, photograph and the score in the final exam with the breakup.It will have the logos of NPTEL and IIT Kharagpur .It will be e-verifiable at nptel.ac.in/noc.

Only the e-certificate will be made available. Hard copies will not be dispatched.

Once again, thanks for your interest in our online courses and certification. Happy learning.

- NPTEL team