The sewerage system, a part from being the widest part of the whole wastewater treatment network, is one of the main components of the hydraulic urban infrastructure: as a matter of fact, the sewers develop in a hundreds and thousands miles long, interconnected net. It is obvious how the monitoring operations of such a complex network turns out to be burdensome not only from a economical point of view, but also from a functional one. For this reason, in the last few years, more and more efforts have been exerted on finding methods to deal with maintenance in a prospective manner. In this thesis two different methods will be defined that have both the aim of classifying the sewers on the basis of their risk of failure and of providing tools that assign to each sewer a monitoring priority in order to then fix an inspection and maintenance plan. The first method, based on an heuristic model, assigns to the inspected conduits, the ones for which all the characteristics are known, first an index of the risk factors and subsequently a global risk index, named HIRC. This empiric method, has not the claim of defining in a precise manner the risk of collapse of the sewer, instead divides the net in five different risk classes. Whereas the other proposed method, grounded on a Bayesian model, has been applied for the sewers that have not been inspected, so to the ones for which is it not possible to define a priori an index of the risk of collapse. In detail, all the evaluations and the analysis have been done for Milan's sewage system.
Le fognature sono una parte fondamentale delle infrastrutture idriche urbane, oltre ad essere la parte più ampia dell’intero sistema di trattamento delle acque reflue: esse infatti si estendono in una rete interconnessa di condotte, lunga centinaia o migliaia di chilometri. Risulta evidente come monitorare costantemente un sistema così complesso sia oneroso sia in termini economici che funzionali. Negli ultimi anni, per questo motivo, si è cercato di trovare strumenti per affrontare la manutenzione delle fognature in modo previsionale. In questa tesi verranno proposti due metodi che hanno l’obiettivo di classificare i condotti fognari in base al loro rischio di crollo e di fornire strumenti che attribuiscano ai collettori una diversa priorità di monitoraggio delle condizioni del condotto e del suo deterioramento e, quindi, stabilendo un piano di ispezioni e di conseguenti manutenzioni. Il primo metodo, di tipo euristico, attribuisce a tutte le condotte già ispezionate, e di cui quindi si conoscono le caratteristiche, un indice dei fattori di rischio gravanti sulla condotta e infine un indice complessivo del rischio di crollo(HIRC). Questo metodo, di natura empirica, non vuole definire in modo puntuale il rischio di crollo dei collettori fognari, ma suddividere le reti in 5 diverse classi di rischio. L’altro metodo proposto invece, è di tipo Bayesiano ed è volto a tutte quelle condotte di cui, per mancanza di dati, non è possibile definire un indice del rischio di crollo a priori. In particolare, tutti i calcoli e le analisi sono state applicate per la rete fognaria di Milano.
Heuristic and Bayesian models for the assestment of sewers' risk of failure
ZACCARDI, STEFANIA;GARISIO, EMMA MARIA
2015/2016
Abstract
The sewerage system, a part from being the widest part of the whole wastewater treatment network, is one of the main components of the hydraulic urban infrastructure: as a matter of fact, the sewers develop in a hundreds and thousands miles long, interconnected net. It is obvious how the monitoring operations of such a complex network turns out to be burdensome not only from a economical point of view, but also from a functional one. For this reason, in the last few years, more and more efforts have been exerted on finding methods to deal with maintenance in a prospective manner. In this thesis two different methods will be defined that have both the aim of classifying the sewers on the basis of their risk of failure and of providing tools that assign to each sewer a monitoring priority in order to then fix an inspection and maintenance plan. The first method, based on an heuristic model, assigns to the inspected conduits, the ones for which all the characteristics are known, first an index of the risk factors and subsequently a global risk index, named HIRC. This empiric method, has not the claim of defining in a precise manner the risk of collapse of the sewer, instead divides the net in five different risk classes. Whereas the other proposed method, grounded on a Bayesian model, has been applied for the sewers that have not been inspected, so to the ones for which is it not possible to define a priori an index of the risk of collapse. In detail, all the evaluations and the analysis have been done for Milan's sewage system.File | Dimensione | Formato | |
---|---|---|---|
Tesi.pdf
non accessibile
Descrizione: Testo della tesi
Dimensione
3.82 MB
Formato
Adobe PDF
|
3.82 MB | Adobe PDF | Visualizza/Apri |
Tesi.docx
non accessibile
Descrizione: Testo della tesi
Dimensione
2.6 MB
Formato
Microsoft Word XML
|
2.6 MB | Microsoft Word XML | Visualizza/Apri |
I documenti in POLITesi sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
https://hdl.handle.net/10589/134478