Ramaglia, Giancarlo (2016) Seismic strengthening of slender masonry barrel vaults: experimental behaviour and analytical modelling. [Tesi di dottorato]

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Item Type:	Tesi di dottorato
Resource language:	English
Title:	Seismic strengthening of slender masonry barrel vaults: experimental behaviour and analytical modelling
Creators:	Creators Email Ramaglia, Giancarlo giancarlo.ramaglia@unina.it
Date:	31 March 2016
Number of Pages:	212
Institution:	Università degli Studi di Napoli Federico II
Department:	Ingegneria Chimica, dei Materiali e della Produzione Industriale
Scuola di dottorato:	Ingegneria industriale
Dottorato:	Ingegneria dei materiali e delle strutture
Ciclo di dottorato:	28
Coordinatore del Corso di dottorato:	nome email Mensitieri, Giuseppe giuseppe.mensitieri@unina.it
Tutor:	nome email Lignola, Gian Piero UNSPECIFIED
Date:	31 March 2016
Number of Pages:	212
Keywords:	Simplified modelling, Barrel vaults, Arch, Shaking table test, Experimental validation, Strengthening systems, Heritage buildings, Seismic capacity assessment
Settori scientifico-disciplinari del MIUR:	Area 08 - Ingegneria civile e Architettura > ICAR/08 - Scienza delle costruzioni Area 08 - Ingegneria civile e Architettura > ICAR/09 - Tecnica delle costruzioni
Date Deposited:	13 Apr 2016 00:01
Last Modified:	31 Oct 2016 11:02
URI:	http://www.fedoa.unina.it/id/eprint/10979

Collection description

The Ph.D. thesis starts from a vulnerability study at regional level. This analysis on a typical historical centre located in the Italian region has been performed. This is a preliminary study in order to assess the main parameters which cause vulnerabilities. The result remarks the influence of local mechanisms in the existing masonry buildings, when there are thrusting elements. For this reason, a structural assessment of masonry vaults, by using a detailed modelling, has been performed. The work focuses on a particular typology of barrel vaults typically used as roofs in religious buildings. These vaults typically do not include any backfill and are slender. These barrel vaults cannot be analysed through the classical approaches where no-tensile strength is assumed. The tensile strength must be included to assess the seismic capacity. Therefore a simplified analytical model, in the framework of limit analysis, is proposed which includes the tensile strength. Tensile strength in these analyses is not only affected by the strength of basic materials, but also by the bond at the unit-to-joint interfaces, which could be rather difficult to assess reliably. The proposed model is useful to have simplified calculations to estimate the increase in capacity of vaulted masonry due to the strengthening interventions. The validation of the analytical model was provided by comparing predictions of the load capacity and the failure mode with those obtained from shaking table tests. The dynamic test used to validate the analytical model has been performed on a full scale masonry vault, previously tested. Starting from the validation of the proposed analytical model, sensitivity analyses have been performed in order to assess the impact of some mechanical and geometrical parameters on the seismic capacity. These analyses were performed using the proposed analytical model. Furthermore, the model, previously validated, has been used in order to design dynamic tests on another masonry vault. The proposed method represents a useful modelling tool to design dynamic tests on masonry vaults and to assess their vulnerability. The dynamic response of the specimen has been investigated by using the shaking table system, before and after application of strengthening systems. In particular, after suffering damage, the vault was repaired and strengthened. Then the strengthened specimen was tested again. The strengthening techniques are based on TRM system (Textile Reinforced Mortar) in addition to traditional strengthening techniques (steel ties and masonry ribs). The performance of the strengthening vault was assessed comparing the behaviour of two specimens (unreinforced and strengthening) during the several tests. In order to support the experimental studies, several FEM analyses have been performed additionally to the simplified modelling. The results are intended as a contribution to the understanding of dynamic behaviour and towards the development of simplified models to estimate seismic capacity of vaulted structures. The experimental results remark the effectiveness of the TRM system coupled with traditional interventions (masonry rib and unidirectional steel tie). In particular, the strengthening system is particularly advisable to safeguard of heritage buildings. In fact, given the high efficiency and compatibility of the strengthening techniques experimentally used, they have been implemented in a real heritage building (Monastery of Santo Spirito, Ocre (Italy)).

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