PSA lezione 1 ottobre 2014 a marked

4. Comportamento di elementi inflessi.pdf

Calcolo della precompressione: DOMINI e STRAUS7

Scopo dell'evento è • illustrare l'identità culturale, e tecnica – di cui il progetto è parte fondante – del SSD Tecnica delle Costruzioni nella didattica, • evidenziando contemporaneamente le opportunità di collaborazione trasversale con altre discipline, • con particolare riferimento ai corsi della lauree magistrali o equivalenti, e livelli di formazione successivi (master e dottorati).

II evento didattica 5 aprile 2022 TECNICA DELLE COSTRUZIONI.pdf

ICAR 09_incontro del 5 aprile 2022_secondo annuncio.pdf

In recent years, there has been an increasing interest in permanent observation of the dynamic behaviour of bridges for longterm monitoring purpose. This is due not only to the ageing of a lot of structures, but also for dealing with the increasing complexity of new bridges. The long-term monitoring of bridges produces a huge quantity of data that need to be effectively processed. For this purpose, there has been a growing interest on the application of soft computing methods. In particular, this work deals with the applicability of Bayesian neural networks for the identification of damage of a cable-stayed bridge. The selected structure is a real bridge proposed as benchmark problem by the Asian-Pacific Network of Centers for Research in Smart Structure Technology (ANCRiSST). They shared data coming from the long-term monitoring of the bridge with the structural health monitoring community in order to assess the current progress on damage detection and identification methods with a full-scale example. The data set includes vibration data before and after the bridge was damaged, so they are useful for testing new approaches for damage detection. In the first part of the paper, the Bayesian neural network model is discussed; then in the second part, a Bayesian neural network procedure for damage detection has been tested. The proposed method is able to detect anomalies on the behaviour of the structure, which can be related to the presence of damage. In order to obtain a confirmation of the obtained results, in the last part of the paper, they are compared with those obtained by using a traditional approach for vibration-based structural identification.

Structural health monitoring of a cable-stayed bridge with Bayesian neural ne...

In recent years, structural integrity monitoring has become increasingly important in structural engineering and construction management. It represents an important tool for the assessment of the dependability of existing complex structural systems as it integrates, in a unified perspective, advanced engineering analyses and experimental data processing. In the first part of this work the concepts of dependability and structural integrity are discussed and it is shown that an effective integrity assessment needs advanced computational methods. For this purpose, soft computing methods have shown to be very useful. In particular, in this work the neural networks model is chosen and successfully improved by applying the Bayesian inference at four hierarchical levels: for training, optimization of the regularization terms, databased model selection, and evaluation of the relative importance of different inputs. In the second part of the article, Bayesian neural networks are used to formulate a multilevel strategy for the monitoring of the integrity of long span bridges subjected to environmental actions: in a first level the occurrence of damage is detected; in a following level the specific damaged element is recognized and the intensity of damage is quantified.

Soft computing based multilevel strategy for bridge integrity monitoring

This paper deals with the general framework for the development and the maintenance of complex structural systems. In the first part, starting with a semantic analysis of the term ‘structure’, the traditional approach to structural problem solving has been reconsidered. Consequently, a systemic approach for the formulation of the different kinds of direct and inverse problems has been framed, particularly with regards to structural design and maintenance. The overall design phase is defined with the aid of the performance-based design (PBD) philosophy, emphasizing the concepts of dependability and enlightening the role of structural identification. The second part of the present work analyses structural health monitoring (SHM) in the systemic way previously introduced. Finally, the techniques related to the implementation of the monitoring process are introduced and a synoptic overview of methods and instruments for structural health monitoring is presented, with particular attention to the ones necessary for structural damage identification.

Systemic approach for the maintenance of complex structural systems

Elenco studenti esaminandi

Costruzione di ponti in cemento armato.

Costruzione di ponti in acciaio

Costruzione di Ponti - Ceradini

The role of softening in the numerical analysis of R.C. framed structures

A numerical approach to the reliability analysis of reinforced and prestressed concrete structures is presented. The problem is formulated in terms of the probabilistic safety factor and the structural reliability is evaluated by Monte Carlo simulation. The cumulative distribution of the safety factor associated with each limit state is derived and a reliability index is evaluated. The proposed procedure is applied to reliability analysis of an existing prestressed concrete arch bridge.

Reliability of material and geometrically non-linear reinforced and prestress...

This paper presents a general approach to the probabilistic prediction of the structural service life and to the maintenance planning of deteriorating concrete structures. The proposed formulation is based on a novel methodology for the assessment of the time-variant structural performance under the diffusive attack of external aggressive agents. Based on this methodology, Monte Carlo simulation is used to account for the randomness of the main structural parameters, including material properties, geometrical parameters, area and location of the reinforcement, material diffusivity and damage rates. The time-variant reliability is then computed with respect to proper measures of structural performance. The results of the lifetime durability analysis are finally used to select, among different maintenance scenarios, the most economical rehabilitation strategy leading to a prescribed target value of the structural service life. Two numerical applications, a box-girder bridge deck and a pier of an existing bridge, show the effectiveness of the proposed methodology.

Probabilistic Service Life Assessment and Maintenance Planning of Concrete St...

This paper presents a novel approach to the problem of durability analysis and lifetime assessment of concrete structures under the diffusive attack from external aggressive agents. The proposed formulation mainly refers to beams and frames, but it can be easily extended also to other types of structures. The diffusion process is modeled by using cellular automata. The mechanical damage coupled to diffusion is evaluated by introducing suitable material degradation laws. Since the rate of mass diffusion usually depends on the stress state, the interaction between the diffusion process and the mechanical behavior of the damaged structure is also taken into account by a proper modeling of the stochastic effects in the mass transfer. To this aim, the nonlinear structural analyses during time are performed within the framework of the finite element method by means of a deteriorating reinforced concrete beam element. The effectiveness of the proposed methodology in handling complex geometrical and mechanical boundary conditions is demonstrated through some applications. Firstly, a reinforced concrete box girder cross section is considered and the damaging process is described by the corresponding evolution of both bending moment–curvature diagrams and axial force-bending moment resistance domains. Secondly, the durability analysis of a reinforced concrete continuous T-beam is developed. Finally, the proposed approach is applied to the analysis of an existing arch bridge and to the identification of its critical members.

Cellular Automata Approach to Durability Analysis of Concrete Structures in A...

The paper deals with the assessment during time of r.c. structures under damage due to diffusion of external agents inside the structure. The diffusion process is modelled by a cellular automata based approach, taking the interaction with the mechanical state of the structures, i.e. the cracking state of the structures, into account. A so-called staggered process then solves the coupled problem. An application shows the effectiveness of the proposed analysis strategy, together some design considerations about the structural robustness. Atti Congresso CTE, Pisa 2000

UNA FORMULAZIONE DEL DEGRADO DELLA RISPOSTA DI STRUTTURE INTELAIATE IN C.A./C...

Esami a distanza. Severgnini. Corriere della sera.

Tdc prova 2022 01-26

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Nguyen Thanh Tu Collection

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Calcolo della precompressione: DOMINI e STRAUS7

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Structural health monitoring of a cable-stayed bridge with Bayesian neural ne...

Soft computing based multilevel strategy for bridge integrity monitoring

Systemic approach for the maintenance of complex structural systems

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Costruzione di ponti in cemento armato.

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The role of softening in the numerical analysis of R.C. framed structures

Reliability of material and geometrically non-linear reinforced and prestress...

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UNA FORMULAZIONE DEL DEGRADO DELLA RISPOSTA DI STRUTTURE INTELAIATE IN C.A./C...

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