International Journal of Masonry Research and Innovation (14 papers in press)
The gothic arcade of Santa Maria Incoronata in Naples. Equilibrium of gothic arches.
by Concetta Cusano, Claudia Cennamo
Abstract: The paper is an application of the structural theory for masonries to a historic building through a static analysis of the shape and stability of the arches of the Incoronata Church in Naples. The previous history of the interventions has been thoroughly investigated by checking the consistency of decisions made over time by engineers and architects who, despite not having modern tools of calculation, designed only by using geometric rules and professional experience. So, a stability analysis is centered on the Gothic Arcade, which has the singularity of a non-symmetrical front and has suffered restoration interventions whose results can be debatable. The analysis conducted is both analytical and graphical, by using the well-known concept of the line of thrust. The obtained equilibrium solution explains the suitability of the arches and the rationality of the intervention in the context of the history of constructions. Although limited to one building, the approach could be applied more generally, with the aim to afford a contribution to the structural knowledge of architectural heritage.
Keywords: masonry; gothic architecture; limit analysis; equilibrium approach.
Sensitivity analyses of seismic performance of ancient mixed masonry-RC buildings in Lisbon
by Jelena Milosevic, Serena Cattari, Rita Bento
Abstract: In the first half of the twentieth century, the mixed masonry-RC buildings were introduced in Lisbon; they were typically designed without strictly considering seismic-design requirements. To assess their potential seismic vulnerability, it is crucial to simulate adequately their actual response by: (i) explicitly considering their characteristics, and (ii) identifying the main parameters that affect their seismic performance. In this context, the aim of the paper is twofold. Firstly, the structural elements are characterized in detail. This first study includes the proposal of reference values for the main mechanical parameters, which are defined by combining various data available in the literature adopting a Bayesian approach. Secondly, to identify the main parameters that affect the seismic response of one type of the ancient mixed masonry-RC buildings, a sensitivity analyses is adopted and implemented; within this context, the influence of different material properties and the quality of connections among structural walls are considered.
Keywords: aleatory and epistemic uncertainties; Bayesian approach; mixed masonry-RC “Placa” buildings; nonlinear static; seismic performance; sensitivity analysis.
Approaches to strongly local phenomena in dry masonry structures
by Fernando Magdalena Layos, Julian Garcia Munoz
Abstract: Sliding collapse tests performed on dry-stack masonry structures show a statistical dispersion in the results that cannot be explained by the dispersion in the properties of its constituent materials, but may correspond to an uneven distribution of stresses at the contact surfaces or within the constituent elements. In order to study these local phenomena, a method of numerical analysis of rigid blocks in unilateral contact is implemented and confronted with two types of benchmark tests: load tests and photoelastic tests. Comparing the results will allow stating that the random irregularities in contact surfaces play an important role in local behaviour. The results are very encouraging and suggest that this type of approach, common in the field of granular media but not in orthotropic media, can provide interesting insights for the analysis of local phenomena in historical masonry structures.
Keywords: masonry structures; numerical analysis; discontinuous media photoelasticity; rigid blocks; unilateral contact; friction.
EFFECT OF CONCRETE BLOCK HEIGHT VARIATION TO THE SHEAR BOND STRENGTH OF THIN LAYER MORTARED MASONRY
by Julian Thamboo, Manicka Dhanasekar
Abstract: Thin layered masonry employs 1 mm 3 mm thick mortar joints laid using simple tools with minimal skilled masons and hence achieve significant saving in the cost of construction. However, the applicability of this masonry system relies on units made with tighter control of their height. Currently unit height variation is tolerated up to
Keywords: Unit height tolerance; thin layer mortared masonry; Shear bond strength; polymer-cement mortar; digital image correlation.
Behaviour of block masonry under in-plane loading
by Roberto Capozucca, Erica Magagnini
Abstract: Knowledge about the behaviour of masonry has increased during the last decades so that codes of practice adopted in many countries allow designing masonry structures on the base of well-defined principles and rules. In the design of buildings, strength of modern masonry under compression and shear is crucial for safety in seismic areas. Modern unreinforced masonry (MURM) built with perforated clay blocks may also be considered adequate in terms of withstanding seismic action without relevant damages. However, the performance of MURM is influenced by many parameters such as solid or perforated units and strength, deformability and thickness of mortar joints. rnIn this paper, the strength of blockwork walls built with two types of perforated clay blocks, lateral surfaces toothed and smooth, and different mortar joints - unfilled vertical joints, shell bedded joints and continuous joints - has been experimentally tested under loading in-plane. An extensive investigation based on compression tests and diagonal compression tests of blockwork walls has been carried out. The experimental results are presented and discussed. In particular, the response of blockwork walls under diagonal tests have been analysed comparing experimental data with that obtained with finite element method (FEM) by macro and micro-modelling, assuming masonry both as an isotropic and orthotropic linear elastic material. rn
Keywords: Blockwork masonry wall; experimental test; shear strength; FE analysis.
Rigid block models for masonry structures
by Maurizio Angelillo, Antonio Fortunato, Antonio Gesualdo, Antonino Iannuzzo
Abstract: The study of masonry mechanics and the modelling of masonry structures requires a methodological approach radically different from the ones used for metallic and concrete structures. The main criteria adopted for the design of the latter, such as strength, stiffness and elastic stability, have a minor role when dealing with masonry structures. Even if this peculiar behaviour, confirmed though a careful historical critique by several authors, such as Heyman with his seminal work of 1966, followed in the 80s and 90 by Di Pasquale, Como, Benvenuto, Huerta, is rather evident, this point of view is far from manifesting itself among structural architects and engineers. Indeed the theory of Heyman, giving a modern turn to the old approach to masonry design by means of clear cut simplifications, is in sharp contrast with the sophisticated constitutive theories made possible by Finite Element methods and the use of super-computers. In these notes, the basic ingredients of a new method based on unilateral equilibrium and rigid block kinematics, which may allow the implementation of Heymans model for masonry on a computer, is introduced. In particular we describe a simple method based on energy minimization allowing the evaluation of the combined effect of loads and settlements on real masonry structures.
Keywords: masonry structures; unilateral constraints; unilateral materials; multi-body structures; contact and friction.
SEISMIC-VOLCANIC VULNERABILITY AND RETROFITTING OF A CULTURAL HERITAGE MASONRY PALACE IN THE VESUVIUS AREA
by Antonio Formisano, Gianmaria Di Lorenzo, Raffaele Landolfo, Federico M. Mazzolani
Abstract: In this paper, the seismic and volcanic vulnerability of a monumental masonry building in the Vesuvius area is assessed in order to setup maintenance and retrofitting measures for upgrading its structural safety. First, the construction seismic behaviour is investigated through modal dynamic and pushover analyses developed by two different computer programs, namely AEDES and SAP 2000, aiming at better understanding the most probable response under earthquake.rnLater on, volcanic analyses under quake and tephra loading conditions have been performed through static non-linear and linear analyses, respectively, with the purpose to implement a building multi-risk investigation. Finally, aiming at removing the detected seismic and volcanic deficiencies, retrofitting and energetic interventions based on the use of metal elements and rock wool insulator, respectively, have been designed and applied to the inspected building. The effectiveness of such interventions has been proved by numerical analyses on the retrofitted building, whose global structural behaviour is resulted to be considerably improved from environmental and seismic points of view.
Keywords: Seismic vulnerability; monumental building; FEM model; metal-based retrofitting techniques; ash fall deposits.
The Response of Concrete Masonry with WidelySpaced Reinforcement to In-plane Shear State of the Art and Research Needs
by Nigel Shrive, Manicka Dhanasekar, Mark Masia, Adrian Page
Abstract: Wide-spaced partially grouted reinforced masonry has vertical reinforcement placed at intervals of more than 800 mm. This type of masonry can fail in additional modes compared to plain unreinforced masonry and masonry where the vertical reinforcement is placed at spacings of 800 mm or less when subject to in-plane shear. We review what is known about the in-plane shear failure of concrete block masonry and the factors that affect the mode of failure. We explain the additional failure mode that wide-spaced reinforcement introduces and review what little is known about that failure and how to predict it. Current codes of practice severely overestimate the in-plane shear strength of this type of masonry. We show that some progress has been made in gaining understanding of the behaviour of wide-spaced reinforced masonry and assess what needs to be investigated in order for design rules to be developed.
Keywords: KEY WORDS: Concrete masonry; wide spaced reinforcement; failure mode; strength.
Surveys on the Jagannath Temple's seismic response in Kathmandu
by Salvatore Russo, Giosuè Boscato, Eleonora Spoldi
Abstract: The objective of this paper is to identify the mechanisms of collapse of the Nepalese wood-masonry monuments damaged by the 2015 seismic event that struck Kathmandu and its valley. The research analyzes the case study "Jagannath Temple" located on Durbar Square in Kathmandu. After a careful anamnesis based on visual inspection and hypotheses on the temple's structural behavior local non-destructive testing (sonic, endoscopic, rebound hammer) was carried out for qualitative characterization of the structural system. These tests have been aimed at a qualitative characterization of the structural structure prior to the study of the collapse mechanisms that characterize the response to the earthquake of these monuments. Specifically, the modal analysis has allowed to characterize the soil-structure restraint while the linear dynamic analysis has highlighted the main criticalities, which characterize the historic construction.
Keywords: Finite Element Analysis; non-destructive test; seismic vulnerability; Nepalese wood-masonry monument; Modal analysis; Linear dynamic analysis.
Comparative analysis of thermal characterization methodologies of a historical double leaf masonry wall
by Cristian Carmona, Gabriel Horrach, Francisco Masdeu, Joan Munoz
Abstract: Energy consumption for heating and air conditioning is one of the main factors to consider in the energy efficiency of buildings. Correctly assessing thermal losses in the envelope is essential for decision making when it comes to minimizing the cost of using thermal installations and improving the thermal comfort of a building.
This paper presents a comparative analysis between different thermal transmittance characterization methodologies. The comparison is carried out between different quantitative methodologies, including that which is described in the Spanish Technical Building Code CTE DB-HE, direct measurement methodologies through an analysis of materials, and in-situ measurements based on the recording of heat flux and temperature differentials as described in ISO 9869. The results of the application of these methodologies on a traditional Mediterranean wall reveal significant differences between each of them. Further, the discrepancies between the default transmittance values and the values obtained through direct measurement of the envelope are determined.
Keywords: thermal characterization; double leaf masonry wall; heat flux analysis; thermal analysis methodologies.
EXPERIMENTAL AMBIENT VIBRATION TESTS AND NUMERICAL INVESTIGATION ON THE SIDONI PALACE IN CASTELNUOVO OF SAN PIO (LAQUILA, ITALY)
by Antonio Formisano, Lidija Krstevska, Gianmaria Di Lorenzo, Raffaele Landolfo, Ljubomir Tashkov
Abstract: In the present paper the experimental and numerical activities related to in-situ Ambient Vibration Tests performed on a monumental masonry building placed in Castelnuovo of San Pio (Italy) are presented. rnThe obtained experimental results, able to identify the dynamic characteristics of the investigated palace, have been successively reproduced by means of a building FEM model through the ABAQUS calculation code. rnNumerical frequency analysis has been also performed on the original building aiming at evaluating its reduction in stiffness due to earthquake. rnFinally, appropriate retrofitting interventions have been proposed, their effectiveness being proved by numerical analyses on the improved palace FEM model.rn
Keywords: Abruzzo earthquake; Ambient Vibration Test (AVT); monumental masonry building; FEM model; vulnerability curves; retrofitting interventions.
Effects of date palm fibres on the mechanical behaviour of stabilized earth blocks:
Case study: Ksar of Kenadsa, province of Bechar (south-west Algeria)
by FOUCHAL Fazia, ZEBAIR Assia, ABDELDJEBAR Rabiâ, HAMOUINE ‎ Abdelmadjid
Abstract: In the field of construction based on raw clay, there is an active search for less costly;stabilizing materials, where exploitation of natural resources for construction has become a ;major concern due to the comon problems of degradation of stabilized earth blocks such those; used in ksour constructions. However, despite the technical, economic and ecological;advantages reported using the stabilized earth blocks (SEB), they remain associated with numerous disadvantages due to the lack of research data in this field, particularly on the ksour constructions located in the saharan region in Algeria. This study contributes to a better understanding of the SEB used in the Kenadsa site, specifically, which are characterized by a mixture of vegetation fibres such as date palm fibres. An analysis is conducted to studying the mechanical properties of specimens prepared from clay collected on the site and mixed to different amounts of fibres and to two different types of stabilizers (cement and / or lime). These two mixtures will enable the selection of optimum fibre dosage and identification of the;most effective stabilizer based on their mechanical strength. The most important points to retain from this contribution are use lime as a stabilizer instead of white cement and the;unfavourable effect of the introduction of date palm fibres into the earth material on the;compressive strength of stabilized earth blocks.
Keywords: Stabilized Earth Blocks; Lime; Cement; Fibres; compression and tensile strength; masonry.
Special Issue on: Seismic Analysis and Rehabilitation Methods of Monumental Masonry Constructions From Past Procedures to Future Advances
Numerical modeling of a Composite pentamode comprising a shear-thickening fluid
by Federico Cecchini, Valeria Cherubini, Francesco Fabbrocino, Francesca Nanni
Abstract: In this work, we developed a novel numerical approach for the analysis of the displacement field of a Composite pentamode material. Two different approaches to the solution of the equations system are taken into account: the first is an exact iterative approach, the second is a discrete one, based on finite element modeling.rnThe single beam elements that materialize the composite pentamode are hollow and comprise a Non-Newtonian fluid (NNF) Core. In particular, Shear-thickening fluids (STFs) were selected as the materials for the core, as they are capable of converting a large quantity of the kinetic energy deriving from the forces applied to the structure into heat.rnIn order to analyze the rheological properties of the material considered, we carried out a two-step rheological analysis.rnFinally, the previous equations were solved and the results obtained for the various solution approaches were compared.rn
Keywords: pentamode; seismic; metamaterial; shear-thickening fluids; constrained layer damping; FEM; viscoelastic damping.
Textile Reinforced Mortars systems: a sustainable way to retrofit structural masonry walls under tsunami loads
by Stefano Belliazzi, Gian Piero Lignola, Andrea Prota
Abstract: Retrofit of existing structures is one of the most demanding and challenging task for practitioners. This is particularly true when dealing with ancient masonry structures and the actions are intense as tsunami loads after an earthquake. The research community is providing newer solutions and systems on the shelf are rapidly changing, in particular improving the compatibility and sustainability both in environmental and conservation fields. Textile Reinforced Mortars (TRMs) represents a good balance between strength provided by fibers and compatibility of mortars by matrix. Main aim of the paper is to provide fast assessment tools for the effects of tsunami actions on masonry structures, assuming as main parameter the inundation depth, and to provide a comparably fast tool to design retrofit interventions with innovative strengthening systems. The peculiar multilinear behaviour of fibrous systems with inorganic matrices, i.e. TRM, is accounted for and some design equations and charts are provided, discussing the peculiarities of the material property variability to orient the designer to coherent and effective decisions, potential uncertainty and variability of substrate masonry are taken into account, too.
Keywords: Charts; Collapse mechanism; Design; Fiber grids; Masonry; Modelling; Mortar matrix; Retrofit; Strength evaluations; Tsunami.