Force-Based Seismic Evaluation of Retrofitting Interventions of Historic Masonry Castles by 3D Rigid Block Limit Analysis

This paper deals with the force-based assessment of collapse mechanisms and strengthening interventions of the historic masonry castle “Bussi sul Tirino” (Abruzzi, Italy) using rigid block limit analysis (RBLA). The structure, which is a fortified palace dating back to the 11th century, has experienced severe earthquakes over the centuries and was hit once again in 2009 by the L’Aquila earthquake. Based on the historical analysis and the results of in situ investigations, a spatial rigid block model of an entire structural unit was generated using the in-house software LiABlock_3D. The software is a MATLAB® based tool for three-dimensional RBLA, which provides as outputs collapse failure modes and collapse load multipliers. In addition, a specific routine was developed for the purpose of the study to compute the participating mass ratio and the spectral acceleration that activated the failure mechanisms. The results of the numerical analysis were used to address three different retrofitting interventions, based on the use of connection elements and ties that, according to the minimum intervention principle, progressively enhanced the seismic capacity. Comparisons in terms of seismic safety indices are finally provided in order to give a quantitative measure of the effectiveness of the adopted retrofitting strategies.

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Seismic Safety Assessment of the “Tekyeh Amir Chakhmagh” by Simplified Kinematic Limit Analysis

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.133-134.653 ◽

2010 ◽

Vol 133-134 ◽

pp. 653-658

Author(s):

Seyed Rohollah Pashanejati ◽

Climent Molins

Keyword(s):

Limit Analysis ◽

Safety Assessment ◽

Failure Mechanisms ◽

Three Dimensional ◽

Masonry Buildings ◽

Seismic Safety ◽

Early 19Th Century ◽

Analysis And Design ◽

Macro Block ◽

Kinematic Limit

This paper presents an investigation about the capabilities of simplified kinematic limit analysis for the safety evaluation and for the design of strengthening of masonry historical buildings. Limit analysis allows, with a reduced number of mechanical properties and for a given ultimate condition of the structure, affordable safety analysis and design of strengthening to the practitioners. Masonry buildings subjected to earthquake show in most cases local failure mechanisms rather than global failure mechanisms due to the lack of integrity of structure. For this reason, simplified kinematic limit analysis has been accepted as a method to design the strengthening of masonry buildings, according to the Italian Ordinance (O.P.C.M. 3431). To validate the applicability of this method, its results had been compared with those provided by three dimensional macro block limit analysis (Bustamante, 2003) for the Via Arizzi house. It is worth noting that results of simplified kinematic limit analysis provided similar results as those achieved by 3D macro block. Also this method was implemented to seismic safety assessment of Tekyeh Amir Chakhmagh in Iran based on the results obtained for the out of plane and in plane behaviour of walls. Tekyeh Amir Chakhmagh is an early 19th century tiled edifice that was built to serve as grand-stand for watching religious rites and also provided an imposing entrance to Amir Chakhmagh bazaar. This stunning three-story facade of the building is one of the most recognizable and unusual buildings in Iran.

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Three-dimensional limit analysis of ancient masonry buildings with rigid block models

High Performance Structures and Materials III ◽

10.2495/hpsm06066 ◽

2006 ◽

Author(s):

A. Orduña

Keyword(s):

Limit Analysis ◽

Three Dimensional ◽

Masonry Buildings ◽

Rigid Block ◽

Block Models

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The Failure of Masonry Walls by Disaggregation and the Masonry Quality Index

Heritage ◽

10.3390/heritage3040065 ◽

2020 ◽

Vol 3 (4) ◽

pp. 1162-1198

Author(s):

Antonio Borri ◽

Marco Corradi ◽

Alessandro De Maria

Keyword(s):

Quality Index ◽

Failure Modes ◽

Structural Response ◽

Theoretical Models ◽

Masonry Walls ◽

Wall Panel ◽

Seismic Capacity ◽

Structural Behaviour ◽

Historic Masonry ◽

Type Of Failure

The visual method for assessment of the structural behaviour of historic masonry walls, known by the acronym MQI (Masonry Quality Index) was introduced in 2002 by a team of researchers from the University of Perugia, Italy. This is based on a visual survey of the faces and the cross section of a wall panel, and it aims at verifying if a wall complies with the “rules of the art”. Based on this analysis, it is possible to calculate a numerical index: numerous tests, carried out on site by the authors to validate the method, have demonstrated that the index is able to provide useful information about the mechanical characteristics and structural response, in general, of the analysed wall panel. The failure mode of a wall panel under the action of an earthquake is a critical aspect. In general, the failure modes can be categorized in two classes: masonry disaggregation and the development of a local or global mechanism of wall elements (macroelements). Several theoretical models and numerical simulations only consider the latter. In this paper, application of the MQI method is further investigated, with particular emphasis to those masonry typologies which are more prone to collapse by disaggregation during a seismic event. Under the action of an earthquake, some types of masonry are typically unable to deform and to split in macroelements, and another type of failure occurs: this is the so-called “masonry disaggregation” or “masonry crumbling”. This type of failure anticipates the ones resulting from macroelement methods or stress analysis. As a conclusion, these latter methods become completely inappropriate and potentially hazardous, as they overestimate the seismic capacity of the building under investigation. The MQI method has been adapted to assess the structural response of different types of masonry under the action of an earthquake. In detail, the aim was to verify when the phenomenon of masonry disaggregation is likely to occur.

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Three-Dimensional Limit Analysis of Dry-Joint Masonry Walls using Rigid Block Modelling

Proceedings of the Fourteenth International Conference on Civil, Structural and Environmental Engineering Computing ◽

10.4203/ccp.102.73 ◽

2013 ◽

Author(s):

F. Portioli ◽

C. Casapulla ◽

L. Cascini ◽

R. Landolfo

Keyword(s):

Limit Analysis ◽

Three Dimensional ◽

Masonry Walls ◽

Rigid Block

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Analytical and numerical seismic assessment of heritage masonry towers

Bulletin of Earthquake Engineering ◽

10.1007/s10518-019-00732-y ◽

2019 ◽

Vol 18 (3) ◽

pp. 969-1008 ◽

Cited By ~ 8

Author(s):

Giacomo Torelli ◽

Dina D’Ayala ◽

Michele Betti ◽

Gianni Bartoli

Keyword(s):

Seismic Risk ◽

Failure Modes ◽

Local Stress ◽

Masonry Structures ◽

Stress Concentrations ◽

Seismic Capacity ◽

Historic Masonry ◽

Existing Structures ◽

Masonry Towers ◽

Kinematic Analyses

Abstract The new Italian building code, published in 2018 [MIT in NTC 2018: D.M. del Ministero delle Infrastrutture e dei trasporti del 17/01/2018. Aggiornamento delle Norme Tecniche per le Costruzioni (in Italian), 2018], explicitly refers to the Italian “Guidelines for the assessment and mitigation of the seismic risk of the cultural heritage” [PCM in DPCM 2011: Direttiva del Presidente del Consiglio dei Ministri per valutazione e riduzione del rischio sismico del patrimonio culturale con riferimento alle norme tecniche per le costruzioni, G.U. n. 47 (in Italian), 2011] as a reliable source of guidance that can be employed for the vulnerability assessment of heritage buildings under seismic loads. According to these guidelines, three evaluation levels are introduced to analyse and assess the seismic capacity of historic masonry structures, namely: (1) simplified global static analyses; (2) kinematic analyses based on local collapse mechanisms, (3) detailed global analyses. Because of the complexity and the large variety of existing masonry typologies, which makes it particularly problematic to adopt a unique procedure for all existing structures, the guidelines provide different simplified analysis approaches for different structural configurations, e.g. churches, palaces, towers. Among the existing typologies of masonry structures there considered, this work aims to deepen validity, effectiveness and scope of application of the Italian guidelines with respect to heritage masonry towers. The three evaluation levels proposed by the guidelines are here compared by discussing the seismic risk assessment of a representative masonry tower: the Cugnanesi tower located in San Gimignano (Italy). The results show that global failure modes due to local stress concentrations cannot be identified if only simplified static and kinematic analyses are performed. Detailed global analyses are in fact generally needed for a reliable prediction of the seismic performance of such structures.

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Application of a Three-Dimensional Rigid Block Model to the Limit Analysis of Large Scale Masonry Panels

Proceedings of the Twelfth International Conference on Computational Structures Technology ◽

10.4203/ccp.106.76 ◽

2014 ◽

Author(s):

F. Portioli ◽

C. Casapulla ◽

L. Cascini

Keyword(s):

Limit Analysis ◽

Large Scale ◽

Three Dimensional ◽

Rigid Block ◽

Block Model

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Scanning Electron Microscopy in Hybrid Microelectronics

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100092244 ◽

1976 ◽

Vol 34 ◽

pp. 456-457

Author(s):

S. Khadpe ◽

R. Faryniak

Keyword(s):

Integrated Circuits ◽

Thick Film ◽

Integrated Circuit ◽

Failure Modes ◽

Three Dimensional ◽

Circuit Components ◽

Hybrid Microcircuit ◽

Electrical Connections ◽

Scanning Electron

The Scanning Electron Microscope (SEM) is an important tool in Thick Film Hybrid Microcircuits Manufacturing because of its large depth of focus and three dimensional capability. This paper discusses some of the important areas in which the SEM is used to monitor process control and component failure modes during the various stages of manufacture of a typical hybrid microcircuit.Figure 1 shows a thick film hybrid microcircuit used in a Motorola Paging Receiver. The circuit consists of thick film resistors and conductors screened and fired on a ceramic (aluminum oxide) substrate. Two integrated circuit dice are bonded to the conductors by means of conductive epoxy and electrical connections from each integrated circuit to the substrate are made by ultrasonically bonding 1 mil aluminum wires from the die pads to appropriate conductor pads on the substrate. In addition to the integrated circuits and the resistors, the circuit includes seven chip capacitors soldered onto the substrate. Some of the important considerations involved in the selection and reliability aspects of the hybrid circuit components are: (a) the quality of the substrate; (b) the surface structure of the thick film conductors; (c) the metallization characteristics of the integrated circuit; and (d) the quality of the wire bond interconnections.

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Compressive behaviours of octet-truss lattices

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406220913586 ◽

2020 ◽

Vol 234 (16) ◽

pp. 3257-3269 ◽

Cited By ~ 1

Author(s):

Yifan Li ◽

Huaiyuan Gu ◽

Martyn Pavier ◽

Harry Coules

Keyword(s):

Failure Modes ◽

Density Ratio ◽

Three Dimensional ◽

Compressive Load ◽

High Strength ◽

Detailed Comparison ◽

Compressive Response ◽

Beam Elements ◽

Structural Applications ◽

Octet Truss

Octet-truss lattice structures can be used for lightweight structural applications due to their high strength-to-density ratio. In this research, octet-truss lattice specimens were fabricated by stereolithography additive manufacturing with a photopolymer resin. The mechanical properties of this structure have been examined in three orthogonal orientations under the compressive load. Detailed comparison and description were carried out on deformation mechanisms and failure modes in different lattice orientations. Finite element models using both beam elements and three-dimensional solid elements were used to simulate the compressive response of this structure. Both the load reaction and collapse modes obtained in simulations were compared with test results. Our results indicate that three-dimensional continuum element models are required to accurately capture the behaviour of real trusses, taking into account the effects of finite-sized beams and joints.

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The Hydromechanical Interplay in the Simplified Three-Dimensional Limit Equilibrium Analyses of Unsaturated Slope Stability

Geosciences ◽

10.3390/geosciences11020073 ◽

2021 ◽

Vol 11 (2) ◽

pp. 73

Author(s):

Panagiotis Sitarenios ◽

Francesca Casini

Keyword(s):

Analytical Solution ◽

Slope Stability ◽

Slope Failure ◽

Failure Modes ◽

Pore Water Pressure ◽

Limit Equilibrium ◽

Water Pressure ◽

Three Dimensional ◽

Stability Limit ◽

Smooth Transition

This paper presents a three-dimensional slope stability limit equilibrium solution for translational planar failure modes. The proposed solution uses Bishop’s average skeleton stress combined with the Mohr–Coulomb failure criterion to describe soil strength evolution under unsaturated conditions while its formulation ensures a natural and smooth transition from the unsaturated to the saturated regime and vice versa. The proposed analytical solution is evaluated by comparing its predictions with the results of the Ruedlingen slope failure experiment. The comparison suggests that, despite its relative simplicity, the analytical solution can capture the experimentally observed behaviour well and highlights the importance of considering lateral resistance together with a realistic interplay between mechanical parameters (cohesion) and hydraulic (pore water pressure) conditions.

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