355 research outputs found
Vulnus Vb 4.0: Procedura automatica per analisi di vulnerabilità sismica di edifici in muratura
No full textAggiornamento ed estensione in Visual basic della procedura VULNUS, di Bernardini-Gori-Modena, 1988. A cura di M.R. Valluzzi, con contributi di Benincà G., Barbetta E., Munari M
Correction to: Understanding of historical masonry for conservation approaches: the contribution of Prof. Luigia Binda to research advancement (Materials and Structures, (2018), 51, 6, (140), 10.1617/s11527-018-1254-4)
No full textThe article ‘‘Understanding of historical masonry for conservation approaches: the contribution of Prof. Luigia Binda to research advancement’’, written by ‘‘Anna Anzani, Giuliana Cardani, Paola Condoleo, Elsa Garavaglia, Antonella Saisi, Cristina Tedeschi, Claudia Tiraboschi, Maria Rosa Valluzzi’’, was originally published electronically on the publisher’s Internet portal (currently SpringerLink) on 16 October 2018 without open access. The copyright of the article changed in December 2019 to © The Author(s) 2019, and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits use, duplication, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made
Optimization of Intervention Strategies for Masonry Buildings Based on CLT Components
No full textUnreinforced masonry has been for centuries one of the most widespread constructive techniques for both massive structures and civil buildings (e.g., palaces, hospitals, houses), for the most still standing nowadays. Their future conservation relies on (i) their protection from main natural threats (e.g., earthquakes) and (ii) updating to current functionality and hygrothermal standards. In the former framework, existing masonry buildings proved to have some intrinsic vulnerabilities, depending on composition (units and binder) and structural typologies. Based on experience gathered from seismic events, various retrofitting techniques have been proposed. In such a context, the use of cross-laminated timber (CLT) components is a very promising solution, in terms of compatibility with built heritage and integration of seismic and hygrothermal performances. This paper aims at improving the knowledge of the structural performances of compound timber-masonry interventions by numerical simulations carried out at (i) pier scale and (ii) building full scale via finite element modeling and nonlinear static analyses (pushover). First, a coupled timber-masonry wall was simulated and underwent sensitivity analyses with the properties of both components varying; then, the optimized solution was applied to a case study to assess the intervention benefits, and the results were also cross-checked with those of more traditional interventions (e.g., grout injections)
Protection of cultural heritage buildings and artistic assets from seismic hazard: A hierarchical approach
No full textThe occurrence of natural disasters such as earthquakes represent a worldwide challenge in the conservation of cultural heritage (CH), which suffer from damage due to high vulnerability conditions. Therefore, the protection of CH from seismic hazard is of paramount importance. Damage and vulnerability assessment of CH and artistic assets play a key role in the identification of conservation strategies. Effective strategies require the stabilization of severely damaged buildings and the preventive improvement of constructions structural response to seismic actions. Although the operation of emergency inspections is meant to classify buildings on the basis of buildings residual seismic capacity, investment decisions in restoration and conservation strategies of such vulnerable structures must take into consideration tangible and intangible values of both building structures and artistic goods as well as must combine objectives of verifying structural safety standards and preserving cultural heritage significance. Damage and vulnerability assessment depend on different criteria, which, on the one hand, are related to buildings structural characteristics, materials, and geometrical properties. On the other hand, to the peculiarities and uniqueness of artworks and artistic goods present on structural elements. In this paper, an AHP (absolute) model is proposed to rank multi-criteria prioritization of protection and restoration interventions on a set of 15 churches, which were damaged by earthquakes, occurring in Italy in the last decades. In detail, in order to structure the decision problem, identify key factors, and define the hierarchy, we conducted an extensive literature review and interviewed a pool of experts. Focus groups were organized to develop the set of criteria and sub-criteria and validate the hierarchy by dynamic discussion
Strengthening of RC beams with an innovative timber-FRP composite system
No full textThe results of a theoretical and experimental research project on the use of an innovative technique for strengthening concrete beams are presented. A spacer element is inserted between the tension side of a beam and the composite material to increase its lever arm and to enhance the over all stiffness of the strengthened beam. The main aim of this exploratory project was to increase the ultimate failure load of strengthened beam specimens, whilst guaranteeing acceptable over all deflections at the serviceability limit states. This resulted into a significant reduction in the amount of FPR required and in a better utilization of the materials employed. A preliminary theoretical study was carried out to investigate the effect of Young's modulus, failure strain, and thickness of the element to be used as a spacer in order to determine the best possible candidate material. Three tests on 2.5-m-long beams were carried out, and different anchorage techniques were used to try and prevent the debonding of the strengthening system. The results from this pilot study are very promising, as the strengthening system ensures an adequate initial stiffness along with an improved ultimate flexural capacity
Testing of bond solutions for UHTS steel strand composites applied to extruded bricks
No full textFibre-Reinforced Polymers (FRPs) are currently a viable and widespread solution for retrofitting masonry buildings, including those of the architectural heritage where interventions need to meet strict requirements. Nevertheless, continuous investigations on possible fibre-matrix combinations and lay-up methods are needed to find further FRP bonding solutions that are possibly more resilient and efficient. In this study an Ultra-High Tensile Strength Steel (UHTSS) fabric was considered as the reinforcement for the FRPs, while either Polyurethane (PU) or epoxy polymers were considered as the matrix. UHTSS fabrics have been introduced in the last decade to overcome some of the limits of common reinforcing fabrics (e.g. carbon, glass, etc.) like, for example, the limited shear resistance that complicates the use of mechanical anchoring for improving the bond of FRPs, especially under peeling stresses. The suitability of PU flexible polymers (Young’s modulus lower than 30 MPa) as matrices for FRPs, in place of the most commonly used epoxy resins, has been investigated in the past few years. Their key characteristic is the diffusion of bond stresses over longer adhesion lengths, with the consequent reduction of peak values. This paper presents and discusses an experimental investigation that compares the bond strength of two Steel-FRP (S-FRP) reinforcements applied to extruded solid clay bricks, made of UHTSS fabric embedded in either a PU or an epoxy matrix. Lastly, two possible lay-up solutions, with one aimed at improving the bond behaviour by inserting an additional interface, are also discussed
Evaluation of the effect of compatible interventions applied to horizontal components of URM buildings with EFM and FEM models. The case of palazzo carraro in Noale (Italy)
No full textURM buildings suffer generally of their weak vertical structure and absence of horizontal connections between the walls. Nevertheless, traditional building practice in Veneto plains, where poor soil conditions are extremely common, required to build very deformable and lightweight houses to adapt to differential foundation settlement. Such peculiar features must be considered in the restoration and adaption to present safety criteria of those buildings. Therefore, 'improvement' interventions as defined by Italian technical standards, rather than structural retrofitting, seems to be more appropriated for reducing both, the alteration of the seismic behavior and the structural weight on foundations. Thanks to the regularity, both in plan and in elevation, of this set of buildings, equivalent frame modeling (EFM) is a viable way to perform global analysis if compared to the complexities of a continuum finite element model (FEM). In the paper, two software will be used for the implementation of the EF model, i.e., TRE Muri and Midas GEN, and their results will be compared with a continuum FE model built with DIANA FEA. In the three models, global seismic behavior through pushover analyses, as the building is and after interventions, is explored. Structural interventions are intentionally limited to horizontal structures stiffening. The case study is represented by a medium sized building placed just outside the old town of Noale, in the metropolitan district of Venice (Italy), dating back to the XVII cent
Conservation of historical constructions in seismic area: experimental research on enhancement techniques for masonry buildings
No full textConservation of CH buildings requires, in the past as today, a deep knowledge of the behaviour of structures and components under deterioration and damage conditions, as well as a suitable experience of the effects of intervention solutions, aimed at enhancing the mechanical performance of the built assets. Seismic hazard constitutes one of the most severe causes of damage and failures for existing structures, particularly for masonry buildings, as they are affected by typical vulnerabilities, due to their constructive systems, degradation of materials, and other specific weaknesses accumulated in the course of time.
A proper selection of materials and techniques is required to face and mitigate those critical conditions, and their validation by experimental research is fundamental, in order to quantify the potential improvement, but also to clarify the contexts of possible restrictions in their use.
The paper presents and discusses a series of intervention techniques adopted in historical masonry building for seismic improvement. Some significant results of experimental research carried out at the University of Padova, aimed at characterizing the performances of modern and innovative materials applied to traditional and more recent or new techniques are also described
Shear strengthening of masonry panels using FRP
No full textThe results of an experimental research carried out on shear strengthened clay brick masonry panels is here presented. Different arrangements of three types of FRP materials have been considered. The comparison among the different conditions in terms of observed behavior and mechanisms of failure is discussed. To predict the shear strength, formulations suggested by the Eurocode 6 and from some researchers have been also considered, and the relevant results have been compared
Il restauro del campanile del Duomo di Monza: scelte di progetto e tecniche di interventol
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