72781 - Earthquake Engineering

Learning outcomes

Students  will learn how to measure the intensity of earhtquakes and of strong ground-motions and will understand the concepts of hazard, vulnerability, and risk. They will learn to quantify seismic hazard and how it is defined by building codes.

Students will learn to analyze the dynamic behaviour of single and multi-degree of freedom structures. They will learn how inelastic behaviour modifies the dynamic reponse of structures, how dutility allows to dissipate energy, and how these factors are implemented by building codes. They will understand performance based desing criteria.

Students will learn to desing reinforced concrete and steel structures according to performance based design criteria, applying capacity design rules as implemented in Eurocode 8. They will learn how to perform nonlinear analyses of structures, with particular focus on nonlinear static analyses.

Studens will learn what are the most widely used seismic protection devices (base isolators and dampers) and understand what are their effects on structures. Students will learn how to assess existing structures.

Course contents

REQUIREMENTS

A prior knowledge and understanding of structural mechanics, structural analysis, and structural design of reiforced concrete and steel structures is required to attend this course. These topics are covered in the following courses: Advanced Desing of Structures and Andvanced Structural Mechanics. A background on the Finite Element method is also recommended. This latter is provided by the Numerical Methods course.

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

CONTENTS

1. SEISMOLOGY FUNDAMENTALS

a. Earth structure, tectonics, faults, faulting mechanisms, earthquake recurrence, elastic rebound theory, magnitude measures, earthquake energy.

b. Accelerograms: recording, properties, basic intensity measures. Soil and topographic effects.

2. STRUCTURAL DYNAMICS OF SDOF SYSTEMS

a. Un-damped free vibrations;

b. Damped free vibrations;

c. Forced vibrations;

d. Response to a base acceleration: Duhamel integral and time-stepping procedures (Newmark method etc.).

e. Elastoplastic SDOF systems.

3. RESPONSE SPECTRA

a. Acceleration, displacement, velocity, pseudo-acceleration and pseudo-velocity response spectra;

b. Soil effects, magnitude effects.

c. Non-linear response spectra: constant strength-reduction-factor spectra, and constant ductility spectra.

d. Ductility- and strength-based design.

4. SEISMIC HAZARD

a. Source models;

b. Recurrence relationships;

c. Attenuation relationships;

d. Deterministic seismic hazard analysis;

e. Probabilistic seismic hazard analysis;

 f. Uniform hazard spectra.

 5. STRUCTURAL DYNAMICS OF MDOF STRUCTURES

 a. Mass, stiffness and damping matrixes;

 b. Modal analysis of plane structures;

 c. Static condensation;

 d. Free vibration;

 e. Response to ground acceleration;

 f. Maximum response analysis (response spectra analysis).

 g. Damping models;

 h. Modal combination rules: SRSS, CQC;

 i. Analysis of 3D structures. Effects of regularity.

 6. SEISMIC DESIGN FUNDAMENTALS

 a. Performance based design: Definition of limit states and performance levels.

 b. Design response spectra: behaviour factor;

 c. Linear analysis methods;

 d. Definition of masses and combination of seismic effects with the effects of other loads;

 e. Capacity design fundamentals.

 7. SEISMIC DESIGN OF CONCRETE STRUCTURES

 a. Ductility classes;

 b. Capacity design of frame structures;

 c. Interaction between walls and frames;

 d. Design of ductile walls.

 8. SEISMIC DESIGN OF STEEL STRUCTURES

 a. Capacity design;

 b. Moment resisting frames;

 c. Concentrically Braced Frames;

 d. Eccentrically Braced Frames;

 e. Buckling Restrained Braced Frames;

 f. Other systems.

 9. NONLINEAR ANALYSIS

 a. Nonlinear beam-column models;

 b. Nonlinear static analysis;

 c. Nonlinear dynamic analysis.

10. ADVANCED SEISMIC PROTECTION TECHNIQUES

a. Base isolation;

b. Dampers.

11. ASSESSMENT OF EXISTING REINFORCED CONCRETE STRUCTURES

Readings/Bibliography

Steven L. Kramer, Geotechnical Earthquake Engineering

C.A. Chopra, Dynamics of Structures: Theory and Applications to Earthquake Engineering

Penelis, G.G. and Kappos, A.J., Earthquake-resistant Concrete Structures

Thomas Paulay and M. J. N. Priestley, Seismic Design of Reinforced Concrete and Masonry Buildings

Teaching methods

Lectures with the support blackboard and powerpoint presentations.

Assessment methods

Achievements will be assessed by means of two homeworks and a final oral exam with an estimated duration of 40 min. They are based on an analytical assessment of the learning outcomes described above.

The oral exam consists of: i) technical and theoretical questions on the contents of the course ii) discussion of the homeworks. In order to obtain a passing grade, students are required to demonstrate a knowledge of the key concepts of the subjects, some ability for critical application, and a comprehensible use of technical language. A failing grade will be awarded if students show knowledge gaps in key-concepts of the subject, inappropriate use of language, and/or logic failures in the analysis of the subject.

The final grade will be computed as follows: 50% homeworks + 50% oral examination

Teaching tools

Blackboard and powerpoint presentations. For the homeworks, educational versions of softwares for structural analysis. Instructional shaking table.

Office hours

See the website of Nicola Buratti

See the website of Marco Savoia