The aim of this thesis is the seismic vulnerability study of a Chinese Pagoda. It is a tower-like masonry structure type, usually massive and tall. They are widely diffused in the Chinese area and they have a great significance in worldwide architectural heritage. Its behaviour under earthquake actions has been highlighted using various analysis typologies. A real case study has been considered: the Longhu Pagoda, located in Xiaoquan, Deyang, Sichuan province. It was built in 1342 A.D. and it is the only still existing masonry pagoda from the Yuan dynasty. This construction hardly suffered the so-called “2008 Sichuan Earthquake”. A full 3D model of the Longhu Pagoda was available. The software Abaqus CAE has been used for carrying out linear static analysis, pushover analysis and non-linear dynamic analysis. The material behaviour has been represented employing the Concrete Damage Plasticity model. A set of numerical and mechanical properties have been hypothesized to model the material and various sensitivity analyses have been performed. The damage reported in each analysis has been deeply commented and the failure mechanisms have been exploited. Moreover, LV1 procedure, as described by Italian Guidelines for Cultural Heritage (2011), has been successfully adapted at the Chinese case study. For the LV1 purpose, an innovative Matlab code able to compute the M-N resisting domain for a generic cross-section has been implemented. It reads the cross-section through its digital image and it finds the resisting bending moment related to a user-defined compressive force acting on the section. This code allows to find the M-N domain for non-trivial cases like complex cross-section geometry and deviated bending. Its results have been carefully analysed and benchmarked. Another innovative tool has been produced: a Matlab code able to compute the M-χ diagram of a generic cross-section. Its results have been used to develop a “manual” pushover analysis procedure: a possible way to perform a pushover analysis without complex and costly software. Its results have been carefully analysed and benchmarked. Finally, two fictitious 3D models of the pagoda have been created adding and removing two floors to investigate the influence of the tower slenderness. Some of the before mentioned analyses have been performed on these models and the influence of the slenderness on this structural typology has been studied.
Lo scopo di questa tesi è lo studio della vulnerabilità sismica di una pagoda cinese. È un tipo di struttura in muratura simile a una torre, solitamente massiccia ed alta. Questi manufatti sono molto diffusi nel territorio cinese e hanno un grande valore nel patrimonio architettonico mondiale. Il comportamento di questa tipologia di struttura sottoposta ad azioni sismiche è stato studiato utilizzando diverse tipologie di analisi. È stato considerato un caso di studio reale: la Pagoda Longhu, situata a Xiaoquan, Deyang, nella provincia del Sichuan. Fu costruita nel 1342 d.C. ed è l'unica pagoda in muratura della dinastia Yuan ancora esistente. Questa costruzione ha subito il famoso "Terremoto del Sichuan del 2008". Era disponibile un modello 3D completo della Pagoda Longhu. È stato utilizzato il software Abaqus CAE per eseguire analisi statiche lineari, analisi pushover e analisi dinamiche non lineari. Il comportamento meccanico del materiale è stato rappresentato mediante il modello “Concrete Damage Plasticity”. Sono stati ipotizzati vari insiemi di proprietà meccaniche e numeriche per la modellazione del materiale e sono state eseguite varie analisi di sensibilità. Il danno riportato in ciascuna analisi è stato attentamente commentato e i meccanismi di collasso sono stati messi in evidenza. Inoltre, la procedura LV1, come descritta dalle Linee Guida Italiane per i Beni Culturali (2011), è stata adattata con successo al caso studio cinese. Per eseguire l’analisi LV1 è stato implementato un innovativo codice Matlab in grado di calcolare il dominio resistente M-N per una generica sezione trasversale. Il codice legge la sezione trasversale attraverso la sua immagine digitale e trova il momento flettente resistente relativo ad una specifica forza di compressione agente sulla sezione. Questo codice consente di trovare il dominio M-N per casi non banali come sezioni con una complessa geometria o la flessione deviata. I risultati sono stati attentamente analizzati e validati tramite esempi noti o calcoli manuali. È stato inoltre creato un altro metodo di analisi innovativo: un codice Matlab in grado di calcolare il diagramma M-χ di una generica sezione trasversale, i cui risultati sono stati utilizzati per sviluppare una procedura di analisi pushover "manuale". Questo è una proposta di un nuovo modo di eseguire un'analisi pushover senza software complessi e costosi. I suoi risultati sono stati attentamente analizzati e validati tramite esempi noti e calcoli manuali. Infine, sono stati creati due modelli 3D fittizi della pagoda aggiungendo e rimuovendo due piani per analizzare l'influenza della snellezza della struttura. Su questi modelli sono state eseguite alcune delle analisi prima citate ed è stata studiata l'influenza della snellezza per questa tipologia strutturale.
Seismic vulnerability of Chinese masonry pagodas
De Iasio, Alessandro
2019/2020
Abstract
The aim of this thesis is the seismic vulnerability study of a Chinese Pagoda. It is a tower-like masonry structure type, usually massive and tall. They are widely diffused in the Chinese area and they have a great significance in worldwide architectural heritage. Its behaviour under earthquake actions has been highlighted using various analysis typologies. A real case study has been considered: the Longhu Pagoda, located in Xiaoquan, Deyang, Sichuan province. It was built in 1342 A.D. and it is the only still existing masonry pagoda from the Yuan dynasty. This construction hardly suffered the so-called “2008 Sichuan Earthquake”. A full 3D model of the Longhu Pagoda was available. The software Abaqus CAE has been used for carrying out linear static analysis, pushover analysis and non-linear dynamic analysis. The material behaviour has been represented employing the Concrete Damage Plasticity model. A set of numerical and mechanical properties have been hypothesized to model the material and various sensitivity analyses have been performed. The damage reported in each analysis has been deeply commented and the failure mechanisms have been exploited. Moreover, LV1 procedure, as described by Italian Guidelines for Cultural Heritage (2011), has been successfully adapted at the Chinese case study. For the LV1 purpose, an innovative Matlab code able to compute the M-N resisting domain for a generic cross-section has been implemented. It reads the cross-section through its digital image and it finds the resisting bending moment related to a user-defined compressive force acting on the section. This code allows to find the M-N domain for non-trivial cases like complex cross-section geometry and deviated bending. Its results have been carefully analysed and benchmarked. Another innovative tool has been produced: a Matlab code able to compute the M-χ diagram of a generic cross-section. Its results have been used to develop a “manual” pushover analysis procedure: a possible way to perform a pushover analysis without complex and costly software. Its results have been carefully analysed and benchmarked. Finally, two fictitious 3D models of the pagoda have been created adding and removing two floors to investigate the influence of the tower slenderness. Some of the before mentioned analyses have been performed on these models and the influence of the slenderness on this structural typology has been studied.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/169234