75460 - Structural Diagnostics and Seismic Assessment M

Learning outcomes

At the end of the class, student has knowledge of the advanced concepts and tools for structural diagnosis, experimental testing and seismic assessment, with special attention for non-destructive techniques and in-situ structural assessment. In particular, at the end of the course he/she is able to assess historic structures, identify typical damage and conduct visual inspections, in situ investigation, non-destructive and slightly destructive techniques. In addition, he/she is able to carry out a seismic assessment, identify response spectrum analysis and damage and collapsing mechanisms in existing (particularly historical) structures.

Course contents

REQUIREMENTS

Fluent spoken and written English is a necessary prerequisite: all the lectures, tutorials, reference documents ad presentations will be in English.

A prior knowledge and understanding of structural mechanics and of the mechanics of masonry structures is required to attend this course. These topics are covered during the following courses: Advanced Structural Mechanics M, Historic Masonry and Wood Structures M.

CONTENTS OF THE MODULUS ON SEISMIC ASSESSMENT 

1. ENGINEERING SEISMOLOGY

a. 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. Ductility and constant ductility spectra .

4. SEISMIC HAZARD

a. Uniform hazard spectra.

5. STRUCTURAL DYNAMICS OF MDOF STRUCTURES

a. Mass, stiffness and damping matrixes;

b. Modal analysis of 2D structures;

c. Free vibration;

d. Response to ground acceleration;

e. Maximum response analysis (response spectrum analysis).

f. Damping models;

g. Modal combination rules: SRSS, CQC;

h. 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. DESIGN OF MASONRY STRUCTURES

a. Design criteria for unreinforced masonry structures

8. SEISMIC VULNERABILITY OF EXISTING STRUCTURES

a. Behaviour of masonry element under lateral loads

b. Analysis methods

c. Local failure modes.

d. Seismic vulnerability analysis of masonry structures

CONTENTS OF MODULUS ON STRUCTURAL DIAGNOSTICS (3 CFU)

1. INTRODUCTION TO THE KNOWLEDGE PATH FOR DIAGNOSE OF HISTORIC MASONRY CONSTRUCTION, VISUAL INSPECTION, SURVEY OF DAMAGE AND CRACK PATTERN MONITORING, EXPERIMENTAL TECHNIQUES FOR MASONRY STATE EVALUATIONS AND DETERMINATION OF MECHANICAL PROPERTIES:

a. in situ destructive, non-destructive, semi-destructive testing with preference to image diagnostic techniques;

b. laboratory testing from site sampling.

2. IN-SITU EXPERIMENTAL TECHNIQUES:

a. coring and sampling;

b. shear strength measurement using hydraulic jack or/and flat-jacks;

c. bond strength measurement using bond wrench;

d. mortar compressive measurement strength using penetrometers;

e. in situ strength measurement by pull-out tests;

f. modulus of eleasticity measurement by using sonic tests;

g. masonry compressive strength measurement using single flat-jacks;

h. deformability and modulus of elasticity measurement by double flat-jacks;

i. diagonal compression in panels

l. IR thermography

m. GPR radar.

3. LABORATORY TESTS

a. compressive strength and modulus of elasticity;

b. splitting tensile stregth using site cores;

c. mortar compressive strength by double punch;

d. splitting tensile test on cores with mortar joint.

Readings/Bibliography

Powerpoint presentations. 

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

V.M. Malhotra, N.J. Carino: “Handbook on Nondestructive Testing of Concrete”, CRC Press, USA, 2004.

M.J. Sansalone, W.B. Street: “Impact-echo”, Bullbrier Press, Ithaca, N.Y., 1997.

Other references will be pointed out to during the course.

Teaching methods

Cognitive and experiential learning. Theory lectures supported by powerpoint presentations and use of blackboard will be alternated with experiential lectures where learning methods include practical exercises and hands-on use of non-destructive equipment, lab demonstrations, site visits. Homeworks.

Assessment methods

Achievements will be assessed by the means of two homeworks (one per modulus) and a final oral exam. They are based on an analytical assessment of the "expected learning outcomes" described above.

The oral exam comprises two parts related to the moduli of the course. Each of these parts consists of: i) technical and theoretical questions on the contents of the corresponding modulus and ii) discussion of the homework. The two parts of the examination are independent and students are allowed to take them in different sessions. In each part, 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 the average of the grades obtained in each part. To obtain a final passing grade passing grades must be obtained in each of the two parts.

Teaching tools

Oral lectures with powerpont presentations. Blackboard. Computer lab. Demonstrations. Lab visit. Site visits. Application examples.

Office hours

See the website of Nicola Buratti

See the website of Camilla Colla