What is essential?

What is essential
Franco Bontempi
School of Civil and Industrial Engineering University of Rome La Sapienza
1

Declaratoria / Declaratory
• Il settore della Tecnica delle Costruzioni si interessa dell’attività
scientifica e didattico-formativa inerente teorie e tecniche rivolte sia
alla concezione strutturale ed al progetto di nuove costruzioni, sia alla
verifica ed alla riabilitazione strutturale di quelle esistenti.
• Tecnica delle Costruzioni is concerned with the scientific and didactic-
learning activities inherent in theories and techniques directed at
both the structural conception and the design of new constructions,
as well as the structural verification and rehabilitation of existing
ones.
7Bontempi – What is essential

• The scientific-disciplinary content concerns:
- building actions, including the effect of seismic action,
- the behavior of structures according to their typology and
morphology, materials, techniques and technologies, soil
interaction and l environment, ways and strategies of use
and control;
- methods and tools for structural design, implementation
and management of structures;
- vulnerability assessments, reliability, comfort, safety and
durability; experimentation, testing and monitoring of
buildings;
- historical surveys on construction, security checks and
structural interventions applicable to historic buildings and
monuments;
- structural architecture.

Bontempi – What is essential
1. Tecnica delle Costruzioni deals with structural design and design: it is a discipline of synthesis -
in which ideas, theories, methods, tools, experimentation and empirical principles come
together - leading to the choice of schemes, elements and components, structural materials,
starting from a solid and broad cultural base.
2. The structural design involves a holistic view of the entire lifecycle of a construction and the
environment in which it is immersed, necessarily envisaging a decision-making path
characterized by assuming responsibility.
3. Structural analysis is the prerequisite for understanding and exploring qualitative and
quantitatively structural behavior in terms of performance and safety: a proper understanding
of the relationship between model and reality is essential for this purpose.
4. The study of real construction cases, particularly in cases of failures, is an essential source of
increased knowledge of the discipline.
5. L’insegnamento della disciplina deve partire dai principi meccanici generali, favorire una valida
comprensione dei comportamenti strutturali elementari e complessivi, predisporre a una
fondata organizzazione della disposizione delle varie parti strutturali supportata da una
coerente scelta dei materiali, aiutare ad individuare le possibili situazioni in cui una costruzione
può trovarsi in termini di azioni e configurazioni.
9
Statements

• La Tecnica delle Costruzioni si occupa della concezione e della progettazione
strutturale: è una disciplina di sintesi - in cui confluiscono idee, teorie, metodi,
strumenti, sperimentazione e principi empirici – che porta alla scelta oculata
di schemi portanti, elementi e componenti, materiali strutturali, partendo da
una solida e ampia base culturale.
• Tecnica delle Costruzioni deals with structural design and design: it is a
discipline of synthesis - in which ideas, theories, methods, tools,
experimentation and empirical principles come together - leading to the
choice of schemes, elements and components, structural materials, starting
from a solid and broad cultural base.
Statement #1

Design method
Problem solving

Constructive attitude
Knowledge of the design
method, how it is done or to
know things, is a liberating value:
it is a "do-it-yourself" yourself.

No archistar

Fundamentals

• L’ergonomia è la disciplina che si occupa dell’interazione tra un
sistema e lo scopo per il quale è progettato, e si propone di
migliorarne la funzionalità rispetto al suo utente.
• Human factors and ergonomics (commonly referred to as HF&E), also
known as comfort design, functional design, and systems, is the
practice of designing products, systems, or processes to take proper
account of the interaction between them and the people who use
them.
25
Ergonomia
Ergonomics

26
Aspetti cognitivi
Cognitive aspects

27
Aspetti cognitivi
Cognitive aspects

28
Esempio
Example

• "But a number of excessive rules involve various of the disadvantages
mentioned above, and in particular:
- the impoverishment of autonomy and creativity, as the work of the designer
is impatient with the norms;
- the difficulty of discerning what really matters;
- the feeling of having, under the shelter of the norms, much relieved
responsibilities;
- the uncommon difficulty to realize the reasoning that justify certain rules,
risking them to be regarded as algorithms, that is, operating patterns that,
once learned, thought is no longer called to justify. "
30
- Proliferazione delle normative e tecnicismo. Ultima lezione ufficiale del corso di Tecnica delle costruzioni
tenuta dal prof. Piero Pozzati nell'a.a. 1991-'92, presso la Facoltà di Ingegneria dell'Università di Bologna (3
giugno 1992).
Excess of Standards

Vn = 100
Cu = 2
q0 = 4
NB:
Caratteristiche
Struttura
Vn = 100
Cu = 2
q0 = 2
Periodo
di ritorno
sisma
Vn = 50
Cu = 1
q0 = 2
Opere ordinarie, ponti, opere infrastrutturali
e dighe di dimensioni contenute o di importanza normale
Grandi opere, ponti, opere infrastrutturali
e dighe di grandi dimensioni o di importanza strategica
31
Statistics
(apparently
scientifically
based)
Human
Decision
(arbitrary)

Failure Path (Reason)

• Il progetto strutturale riguarda con una visione olistica tutto il ciclo di vita di
una costruzione e l’ambiente in cui è immersa, prevedendo necessariamente
un percorso decisionale caratterizzato da assunzione di responsabilità.
• The structural design involves a holistic view of the entire lifecycle of a
construction and the environment in which it is immersed, necessarily
envisaging a decision-making path characterized by assuming responsibility.
Statement #2

RESILIENCE

40
Luxury is the manifestation of the
uncivilized wealth that wants to
impress who is poor.
It is the manifestation of the
importance that is given to the
exteriority and reveals the lack of
interest in the whole cultural
elevation.
It's the triumph of appearance on
the substance.
Disvalori
Anti-values

Simplifying means trying to solve the
problem by eliminating everything that is
not needed to perform the functions
Simplifying is to reduce costs, reduce
machining, assembly, and finishing times.
One wants to solve two issues together in
one solution. Simplifying is a hard work and
requires a lot of creativity.
Complicating is much easier, just add
anything what comes to your mind without
worrying if costs go beyond sales limits,
you take more time to realize the object,
and so on.
Valori
Values

It is necessary, however, to say that the general
public is more inclined to evaluate the manual
"so much work" that it takes to do a
complicated thing than to recognize the "so
much work" mental that it wants to simplify,
since then you can not see it.
Indeed, people in the face of simple solutions,
which may have required lengthy research and
trials, say: but how, is everything here? but this
I knew I did too!

It is important to consider things
not only for what they are, but
also for what they might be.
Generally, the same thing can be
looked at in many respects, and
sometimes the less obvious
points of view are most useful.
It's always worth it, when
something is happening for what
it is, to go deep into the exam to
see what else it might be.
Sostenibilità
Sustainability

• L’analisi strutturale è il presupposto per capire ed esplorare qualitativamente
e quantitativamente il comportamento strutturale in termini di prestazioni e
sicurezza: la corretta comprensione della relazione fra modello e realtà è
essenziale a tal fine.
• Structural analysis is the prerequisite for understanding and exploring
qualitative and quantitatively structural behavior in terms of performance
and safety: a proper understanding of the relationship between model and
reality is essential for this purpose.
Statement #3

START
END
MODIFICA
K=K+1
K=0
DATI
K
CALCOLO
RISULTATI
K
TEST
SI’ NO
ANALYSIS
SYNTHESIS
49
Analysis vs Synthesis
Synthesis is the combining of the
constituent elements of separate
material or abstract entities into a
single or unified entity (opposed to
analysis as the separating of any
material or abstract entity into its
constituent elements).

UsualULS&SLS
VerificationFormat
Structural Robustness
Assessment
1st level:
Material
Point
2nd level:
Element
Section
3rd level:
Structural
Element
4th level:
Structural
System
51
Level of Structural Failures

Bad vs Good Collapse
STRUCTURE
& LOADS
Collapse
Mechanism
NO SWAY
“IMPLOSION”
OF THE
STRUCTURE
“EXPLOSION”
OF THE
STRUCTURE
is a process in which
objects are destroyed by
collapsing on themselves
is a process
NOT CONFINED
SWAY

53
Rappresentazione
grafica
Visual
Language

STRUCTURAL
QUALITY
- design life
- railway
runability
- highway
runability
- free channel
- robustness
- durability
- management
GLOBAL
GEOMETRY
AND
TOPOLOGY
TOPOLOGY
- suspension system
- towers
- towers foundation
- anchor system
- main deck
- deck landing
- ...
GLOBAL GEOMETRY
- main span
- sx span
- dx span
SECTIONAL GEOMETRY
- continuous girder sections
- transverse section
- main cables
- hangers
- towers
- secondary elements
MATERIALS
CHARACTERISTICS
- girders
- cables
SYNTHESIS OF
STRUCTURAL
SOLUTION
AND
DOCUMENTATION
BOUNDARY
CONDITIONS
CONSTRAINTS:
rigid and elastic
constraints,
imposed
displacements
NATURAL
ACTIONS
- temperature
- wind
- earthquake
ANTROPIC
ACTIONS
a) permanent
loading
system
b) variable
- railway
- highway
c) accidental
CONVENTIONALMODELING:
QUASISTATICREPRESENTATION
BASIC STRUCTURAL
CONFIGURATION
PARAMETERS
- individuation
- definition
- uncertainty
- description
- bounding
GLOBAL
MODELING
- 2D
- 3D
MODELING WITH
DYNAMIC INTERACTION
ALTERNATIVE STRUCTURAL
CONFIGURATIONS
GLOBAL
OPTIMIZATION
- topology
- morphology
- parametric
LOCAL
OPTIMIZATION
- girders section
- transverse
section
- restraint zone
EXPERT AND
FIXED CHOICES
MEASURES
a) qualitative
b) materials volumes
c) serviceability
- modal characteristics
- deflections
- deformations
- reversibility
d) collapse scenarios
- collapse characteristics
- robustness
e) accidental scenarios
- configurations
- risks
DETAILED
MODELING
EXTENDED
MODELING
1
2 3
4
5
6
7
Numerical Modeling for the
Structural Analysis and Design of
MESSINA STRAIT BRIDGE:
subdivision and development of activities.
FB - june 6, 2005 / franco.bontempi@uniroma1.it

• But, in addition to these observations, it seems appropriate to conclude by
observing in general that, with regard to the methods of calculation and the rules,
it should be avoided to give them too much importance, in order not to shadow the
actual design.
• Which has only one of its phases, even if it is fundamental, while in other matters it
is equally qualified: above all I mean the general conception of structures; the
harmonious distribution of masses; the constructive details; analysis of executive
and cost problems; the critical examination of the general construction behavior
including, and not only, the presence of non-structural elements and the part of the
soil involved in the structure. These are those who have to get into the living of the
design process, becoming a unique force each time.
• Facts that can not be comprehensively acquired by numerical elaborations and
computers as they can, however, succeed in making the human mind with the
irreplaceable auxiliaries, peculiar to it alone, intuition, inventiveness, imagination,
and creativity.
57
- IL CONVENZIONALISMO NEL CALCOLO STRUTTURALE SISMICO – P. Pozzati 5 marzo 2004

• Lo studio di casi reali di costruzioni, in particolare nei casi di fallimento, è
fonte essenziale di aumento di conoscenza della disciplina.
• The study of real construction cases, particularly in cases of failures, is an
essential source of increased knowledge of the discipline.
Statement #4

65
The Almö Bridge (inaugurated in 1960), that connected the island of
Tjörn (Sweden's 7th largest island) to the mainland. The bridge collapsed
January 18th 1980, when the bulk carrier MS Star Clipper struck the
bridge arch. Eight people died that night as they drove over the edge
until the road on the Tjörn side was closed 40 minutes after the
accident. A new cable-stayed bridge, Tjörn Bridge, was built and
inaugurated in 1981.

Direct vs. Inverse Problems
Back-analysis
Forward-analysis
Direct problem
Inverse problem

COSE – STRUTTURE - SISTEMI
THINGS – STRUCTURES - SYSTEMS
PERSONE – COMPORTAMENTI
PEOPLE – HUMAN BEHAVIOR
COSA
WHAT
CHI
WHO
ROTTURA – COLLASSO - CRISI
FAILURE – COLLPASE - CRISIS
PERCHE’
WHY
SPIEGAZIONE – CAUSE
REASON - DISCLOSURE
CONOSCENZA
KONWLEDGE
Aumento conoscenza – Knowledge gain

http://territorio.regione.emilia-romagna.it/codice-territorio/sismica/dossier-sentenze-
della-causa-penale-conseguente-al-crollo-delledificio-scolastico-jovine-di-san-giuliano-di-
puglia 68

• L’insegnamento della disciplina deve partire dai principi meccanici generali,
favorire una valida comprensione dei comportamenti strutturali elementari e
complessivi, predisporre a una fondata organizzazione della disposizione
delle varie parti strutturali supportata da una coerente scelta dei materiali,
aiutare ad individuare le possibili situazioni in cui una costruzione può
trovarsi in termini di azioni e configurazioni.
• The teaching of the discipline must start from the general mechanical
principles, promote a good understanding of the elementary and overall
structural behaviors, prepare for a well-structured arrangement of the
various structural parts supported by a coherent choice of materials, help to
identify the possible situations where a construction can be in terms of
actions and configurations.
Statement #5
73

Spazialita’
Spatiality

A
B
C
D E
F
G
H
B - and D - Regions

85
Bernoulli-Navier Beam Model

Drucker Beam Model

Ritter-Morsch Truss Model

88
Modelli di
Progetto
Design
Models

Stringer-Panel Model

90
Load Path: the flow of loads

Load Path: knowledge

Structural System

93
Sistema
Strutturale
Structural
System

94
94
Raccolta/Collection Trasmissione/Transfer Stabilizzazione/Bracing

• Micro-level:
local size of the sections, i.e. thickness, area, inertia, …
(Detailed Geometry)
• Meso-level:
form of the structural element or structural part (substructure), i.e.
main longitudinal axis, curvature, profile, …
(Global Geometry)
• Macro-level:
connections of the different structural parts
(Load Path)
Structure Essential

Micro-level:
local size of the sections,
i.e. thickness, area,
inertia, … (Detailed
Geometry)
Meso-level:
form of the structural
element or structural part
(substructure), i.e. main
longitudinal axis, curvature,
profile, … (Global Geometry)
Macro-level:
connections of the
different structural
parts (Load Path)
Optimization Levels

• Spazialità
• Comportamento trave (B-regions)
• Regioni diffusive (D-regions)
• Modelli discreti traliccio/graticcio
• Modelli di progetto (S&T – SPM)
• Percorso dei carichi
• Sistema strutturale
• Nonlinearità
• Imperfezioni e incertezze
97
Concetti chiave – Key Concepts
• Spatiality
• Basic beam behavior (B-regions)
• Diffusive regions (D-regions)
• Discrete models (truss/gridworks)
• Design models (S&T – SPM)
• Load path
• Structural system
• Nonlinearity
• Imperfections and uncertainty

Academics

Titolo 11- ASN
• Specifiche esperienze professionali caratterizzate da attività di
ricerca attinenti al settore concorsuale per cui è presentata la
domanda per l'abilitazione.
• Il titolo verrà riconosciuto nel caso di esperienze professionali
caratterizzate da problematiche complesse, affrontate con approcci
e metodi non standard.

102
It was the task of the Engineering Schools to teach about artificial things: to explain how
artifacts have the properties they want and how they are designed. ...
Given the fundamental role that designers undertake in professional activities, it is an irony
that in this century the Natural Sciences have driven the Science of Artificial training from
their courses. ...
The tendency toward natural sciences and the removal from the Science of Artificial have
occurred more and more quickly in Engineering, Economics ... than in other professional
fields. ... there are few doctoral dissertations dealing with authentic planning problems
considered something different from the problems of solid state physics or stochastic
processes. ... This universal phenomenon must have a root cause.
And, in fact, it has one completely obvious. As vocational schools, including polytechnics,
are increasingly absorbed by general university culture, aspiring to academic respectability.
And, according to today's dominant standards, academic respectability means subjects that
are intellectually difficult, analytic, and can be formalized and taught.

Bartolo Nigrisoli
103
«Il concetto morale del carattere e della dignità umana, che mi aveva aperta la strada alla cattedra fu
lo stesso che mi fece destituire, essendo sotto il fascismo il bene morale diventato un male»

104
On October 8, 1931, Mussolini imposed on university
professors the oath of allegiance to fascism. About a
thousand ordinary people only twelve refuse to bend
to the duce, losing the chair, and undergoing a massive
isolation in the massively subdued regime in Italy.
Twelve men, different by origin, character, ways of
thinking, social attitudes, in that autumn of 1931
impart the most masterful of the lessons teaching that
saying no is a choice first of all to themselves.
Ernesto Buonaiuti, Mario Carrara, Gaetano De Sanctis,
Giorgio Errera, Giorgio Levi Della Vida, Fabio Luzzatto,
Piero Martinetti, Bartolo Nigrisoli, Francesco and
Edoardo Ruffini, Lionello Venturi, Vito Volterra - these
names of those who make an essential gesture in the
name of those "ideals of freedom, dignity and inner
consistency" in which they grew up.

Lezione #03:
MODELLAZIONE
STRUTTURALE
Franco Bontempi
Professore Ordinario di Tecnica
delle Costruzioni
Facoltà di Ingegneria Civile e
Industriale
Sapienza Università di Roma
franco.bontempi@uniroma1.it
113

Fenomeni di aderenza/scorrimento
114

123
https://www.youtube.com/channel/UCW3IyXTBJVIiS6OZeSdIN7g

124
https://fr.linkedin.com/in/francobontempi

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