LEARNING OUTCOMES

Classification of structural retrofitting interventions on existing buildings: maintenance, damage repair, local interventions, overall strengthening. Strategies for the choice of interventions: force versus deformation capacity, reversibility, durability, cost-benefit analysis. From the diagnosis to the design of interventions (monitoring, provisional works). Conceptual classification of strengthening techniques: traditional solutions versus use of innovative materials. Masonry buildings: foundations; masonry walls (cracks repair, widespread strengthening, improvement of connections); arches and vaults; floors and roof (bending strengthening, diaphragm effect); local interventions (creation of new openings or framing of existing ones); seismic improvement. Reinforced concrete structures: restoration of concrete; reinforcement of elements and nodes with composite materials; dissipative bracings; selective weakening and use fuse (elements of sacrifice).

TEACHING METHODS

Frontal theoretical lessons
Guided exercises carried out by the teacher

SYLLABUS/CONTENT

1. Structural safety of buildings: from “trial & errors” approach to engineered structures; examples of collapses (gothic cathedrals, San Marco bell tower in Venice, Civic Tower in Pavia, Noto Cathedral, Assisi and the earthquakes, …); other causes (fire in Notre Dame, lightning); examples of wrong interventions; the importance of monitoring and maintenance; diagnosis and interventions; classification of interventions in terms of aim (maintenance, damage repair, strengthening (improvement), retrofitting).
2. Structural assessment of existing buildings in codes: when it is necessary: proved errors, accelerated decay, change of use, damage, natural events; difference between design and assessment; mandatory rules versus recommendations; the probabilistic approach: reference time and nominal life of the building; qualitative versus quantitative approach; optimization of intervention: safety, conservation and cost; conservation issues: reversibility, non-invasiveness, authenticity and durability; classification of interventions in terms of functionality: substitution of ineffective elements, integration with new elements, integration with new structural systems, new structure.

Masonry buildings

1. The structural system: brief historical notes on the structural details and the use of materials; evolution of masonry (constitutive elements and arrangement); mechanics of masonry as a composite material (homogenization, equivalent properties, local failure criteria); mechanics of masonry elements.  
2. Interpretation of crack patterns: examples of patterns due to different instabilities: settlements, compression failure, thrusting arches/vaults, etc.; criteria for surveying; monitoring: technical options and interpretation; the SHM (tools and alerts).
3. Limit analysis of masonry structures: rigid blocks and kinematic constraints; the use of safe (static) and unsafe (kinematic) theorems; application to arches, vaults and domes; the effect of friction; the influence of crushing. 
4. Provisional interventions: classification in terms of aim (supporting, restraining, wrapping, ecc.); traditional and innovative solutions; design criteria; examples.
5. Strengthening of foundations:
6. Repair of cracks:
7. Strengthening of masonry:
8. Improvement of connections: between masonry walls; connection of horizontal diaphragms to masonry walls; in-plane stiffening of horizontal diaphragms.
9. Strengthening of horizontal floors:        
10. Strengthening of vaults and domes:
11. Integration of the structural system to horizontal actions:

Reinforced concrete buildings

1. The structural system: brief historical notes on the evolution of structural systems and details; material properties and deterioration; seismic vulnerability of pre-code r.c. buildings.   
2. Repair of cracks and deterioration:
3. Strengthening of r.c. elements: beton-plaquè; use of FRP; innovative solutions 
4. Integration of the structural system: adding r.c. walls (by filling void in the frame or strengthening masonry infills); adding bracing elements (also with passive or semi-active devices); putting beside a new structural system for horizontal actions
5. Base isolation

RECOMMENDED READING/BIBLIOGRAPHY

Course notes, available on AulaWeb.

Recording of the lessons on Teams.

M. Pisani. Consolidamento delle strutture. Hoepli. 2008.

S. Mastrodicasa. Dissesti statici delle strutture edilizie. Hoepli. 1993.

M. Como. Statica delle costruzioni storiche in muratura. Aracne. 2015