35436 - Mechanics of Historical Masonry Structures

Learning outcomes

The goal of the course is to provide the students with the fundamentals for the analysis of historical masonry structures. In particular, the course treats the theoretical aspects, the numerical tools and the experimental techniques for an effective structural diagnosis of histrorical structures aimed at preservation and rehabilitation. Structures from different periods of histrory are analyzed.

Course contents

Version Dec. 2012

CIVIL ENGINEERING

MECHANICS OF HISTORICAL MASONRY STRUCTURES

1° CICLO 6CFU = 60 ORE FRONTALI

The course covers the Analysis of Masonry behaviour under complex loading conditions.

The Masonries considered are regular brick or worked natural stone systems.

Contents 2012

PRELIMINARY ASPECTS (5 h.)

Masonry Systems in Historical Constructions:

Conservation politics and Terminology (Prolusion/prelude).

Relevant phenomenology regarding collapse: spontaneous implosion, seismic injure

Earthquake events and damage to Historic Construction in Emilia (2012)

Special survey on towers and campanili during seismic events in Emilia (2012)

Provisional support and Reconstruction (Conference).

PART ONE Standards and Experimental Evidence (20 h. / four weeks)

1. Morphology and materials of historical masonries (stonework/ashlar or rubble,

Brickwork/ Flemish or English bond).

2. Standards on masonry construction: Eurocode 6, Italian code, U.S. code (TMS 402-08/ACI 530-08/ASCE 5-08). Linee Guida MiBAC.

3. Experimental evidences on Tests of lapideous (cohesive) materials evaluating mechanical parameters. Constitutive relationships (experimental) for Lapideous materials.

3.1 Units and Mortars,

3.2 Regular Brick Masonry: characterisation on specimens ( Literature Review:

experimental data - tension orthogonal to bed-joints, compression

orthogonal to bed-joints, shear properties parallel to bed-joints, principal stress at different

orientations,)

3.4 Regular Stone (Volcanic Tuff, Calcarenite) Masonry: characterization on specimens 4. Non-destructive evaluation of masonry mechanical properties and stress state in situ (flat jack, penetrometer or Darmstadt test (mortar evaluation), sonic and ultrasonic waves, radar-grafia, ambient vibration record for identification, acoustic emission analysis for fracture evolution).

PART TWO Theories and Models

0. Revised concepts and formulas (tensor, Invariants, Deviator, Mohr circles)

1. Macroscopic criteria of local crisis and Fracture limit surfaces for lapideous materials (Mohr- Coulomb_Tension cut-off_capped, Drucker-Prager, Willam-Warnke).

2. Basic Concepts of Linear Elastic Fracture Mechanics (Griffith and Irwin problems) and Fracture models of dominant crack in cohesive materials (Hillerborg fictitious crack, Fracture Energy and Size effect, softening vs. hardening, Bazant smeared crack)

3. Micro-models of masonry

4. Macro-models of masonry. Continuum models for masonry as a composite.

5. Static theories of masonry structural elements (arches, vaults)

6. Numerical models in numerical simulation library programs about MHMS

7 Approach with Macro-elements for analysis of seismic behaviour: mechanisms of collapse and architectural vulnerability, collapse inhibitors.

PART THREE Case Histories

A. Churches (s.Pietro da Coppito-AQ)

B. Towers ( Torrazzo Gonzaga- RE, Ghirlandina-MO/ PND, Civic Tower in Ravenna )

C. Bridges (Rialto-VE)

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NOTE:

The bibliography will be delivered during lectures.

The ppt presented by the teacher during the course will be deposited on unibo site for

downloading. This ppt is only a part of the lectures; the remaining part is

presented orally and written on blackboard.

Assessment methods

Intermediate presentation of personal work by students, written questions and oral colloquium as final exam.

Teaching tools

The ppt presented by the teacher are up-loaded on the web site of university (Digital Librery of University of Bologna). The blackboard notes of teacher must be copied by students on personal block notes and presented and discussed at oral exam.

Office hours

See the website of Angelo Di Tommaso