International Journal of Masonry Research and Innovation (25 papers in press)
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.
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.
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.
Influence of Amorfous nano-silica addition on properties of fresh cement paste and hardened cement mortar
by Belkessam-Hamzi Samia, Abdelbaki Benmounah, Brahim SAFI
Abstract: the objective of this study is to explore the effect of incorporating nano-silica to local cement on consistency, setting time of the cement paste and and the properties of hardened mortars. Ordinary portland cement was replaced with an amorphous nano-silica (NS) with average particle size of 12 nm (Aerosil 200 type) or micro silica fume (FS) with average particle size of 0.1
Keywords: Nano-silica; Silica fume; cement paste; mortar; DTA-GTA; XRD; mechanical strength; flexural strength.
Natural Properties of Confined Masonry Buildings-- Experimental Case Studies and Possible Inferences
by Harshit Nema, Dhiman Basu
Abstract: Construction of faculty housing and students hostels in a fully-residential 400-acre academic campus of Indian Institute of Technology Gandhinagar(IITGN) in the State of Gujarat, India is the first large scale confined masonry construction in the country. Knowledge of dynamic properties of these buildings will provide valuable inputs to the seismic design recommendations of confined masonry buildings. Ambient and forced vibration tests (AVT and FVT) are conducted in some of the constructed buildings for the natural period and damping ratio. This paper presents the details of such case studies and compares the experimental results with general expectation considering reinforced concrete buildings with infilled masonry wall as the basis. Also recommended in this paper are some of the fine tuning in the experimental framework of conducting AVT and FVT, and processing the recorded data to identify the natural frequency with greater confidence level.
Keywords: Ambient vibration testing (AVT); Forced vibration testing (FVT); Confined masonry buildings; Dynamic properties;.
A limit analysis approach for masonry domes: the basilica of San Francesco di Paola in Naples
by Concetta Cusano, Claudia Cennamo, Maurizio Angelillo
Abstract: The object of the present study is the basilica of San Francesco di Paola, an historical structure that well lends itself to use the graphic method of statics to analyse its stability for a twofold reason: on the one hand it is an interesting structure being dominated by a dome of considerable size with a solid appearance, and on the other, it is an entirely masonry structure for which no consolidation interventions with different materials have been necessary so far. This paper applies Limit Analysis based on the geometric equilibrium of the dome starting from detailed surveys of the church, from the knowledge of its history construction to the comprehension of the entire building. In a further analysis we go on to examine its structural behaviour through combined methods of graphic statics such as the slicing technique and the thrust line, which are far beyond the issues inherent to resistance, but rather refer to the methods of the ancient builders. Through the case study, this research demonstrates the potential of the graphical method of statics as a mean to understand the equilibrium of compression-only structures, such as masonry domes whose geometry constitutes the structure as an important role in the safety evaluation. The study carried out enriches previous researches developed around the same case study, and the new contribution is integrated by the analysis of stability of the buttress system that completes the work on the vertical loads, providing a more detailed assessment of the safety level of the structure.
Keywords: masonry domes behaviour; limit analysis; safety evaluation.
Monotonic tests on masonry elements with different angles of inclination of the bed joints under uniaxial compression
by Weber Marius
Abstract: This paper describes the results from monotonic tests performed on masonry elements with different angles of inclination of the bed joints relative to the horizontal under uniaxial compression. Two different types of bricks (calcium-silicate and clay bricks) were tested under uniaxial compression stress state. The main test parameter was the angle of inclination of the bed joints, which was varied between 0 and 90 degrees in the interval of 15 degrees. The tests were performed in displacement control in order to capture the post-peak response of the masonry elements as well. The applied displacements were increased monotonically. During the tests, main measurements were performed to measure the edge deformation, detection of strain on the masonry surface using a photogrammetric method, and documentation of the crack propagation and fracture behavior. The strength and the stiffness properties, as well as stress-strain relationships as a function of the angle of inclination of the bed joints and the comparison between the principle directions of stresses and strains is reported here.
Keywords: compression test; inclined bed joints; monotonic loading; macromodel.
Validation of a two-step simplified compatible homogenization approach extended to out-plane loaded masonries
by Elisa Bertolesi, Luis Silva, Gabriele Milani
Abstract: A two step homogenization model already formulated by the authors for the non-linear analysis of full scale structures in-plane loaded is herein extended to out of plane loaded masonries. A rectangular running bond elementary cell is discretized by means of twenty-four elastic CST elements and inelastic zero-thickness interfaces. In the present paper, the mechanical problem at the meso-scale is briefly recalled, whereas the out of plane homogenized stress-strain behaviour is evaluated by means of a simple on-thickness integration of the in plane homogenized curves deduced at the level of the elementary cell. At the macro-scale, the Rigid Body and Spring model is slightly modified in order to allow the development of both flexural (vertical and horizontal) and torsional failure mechanisms. The paper discusses the extension of the two step in-plane homogenization procedure to out of plane loaded masonries. A validation of the numerical outcomes is achieved adopting some full-scale masonry panels tested by Griffith and co-workers. To this scope, a series of non-linear structural analyses are conducted taking into account different parameters which have been varied during the experimental campaign. The numerical outcomes showed a satisfactory agreement in all the proposed simulations and evidenced the capability of the proposed approach to deal with different failure mechanisms as result of a combination of various experimental aspects.
Keywords: Masonry; in-plane loads; out of plane loads; semi-analytical approach; compatible model of homogenization.
Macroelement and dynamic seismic analysis of the medieval government building of Perugia, Italy
by Marco Corradi
Abstract: This paper emphasizes the actual structural analysis of a multistory medieval building, located in Perugia, Italy, for seismic resistance. This is the local Governor building of the capital city of Umbria, known as Palazzo dei Priori, an iconic grade-I stone masonry construction. Strong emphasis is placed on specific issues, critical for the structural response of the building under the seismic action. Fundamental assessment methods are presented and discussed to find vulnerabilities and defects that affect its seismic response. The discussion includes the analysis by macro-elements (local analysis), leading to the identification to the most likely collapse mechanisms of the building under the seismic action. In addition to the macro-element method, a non-linear analysis is given for the whole building. All the used analyses are carried out with reference to the Italian guidelines for heritage protection and conservation and by considering the architectural and artistic assets of the building.
Keywords: Historic masonry; earthquake engineering; numerical modelling; seismic assessment.
Testing and Analysis of Masonry Hollow Clay Block Prisms Filled with Mortar
by Marcio Nascimento, Humberto Roman, Fernando Fonseca
Abstract: In some design situations, in construction systems with structural masonry, an increase in the capacity of the walls is required, which can be achieved with the filling of empty cells of masonry blocks with grout. The Brazilian technical standard for clay masonry blocks aiming at attaining greater agility and flexibility in the construction process allows the use of bedding mortar instead of grout to fill the cells of the blocks. In this context, the objective of this study was to evaluate the mechanical behavior of prisms filled with bedding mortar. Six classes of mortar and one type of clay block with nominal resistance of 6 MPa were studied. The results of the compressive strength of the prisms indicate the viability of using bedding mortar with the same structural function as grout.
This article presents also an analytical study to evaluate the mechanical behavior of clay block prisms filled with mortar. Analyses were conducted using a general-purpose, nonlinear finite element software that simulates structural behavior under different loading scenarios. A three-dimensional model of the prisms was developed using 8-node brick elements for both block and mortar with non-linear properties assigned to each material.
Keywords: structural masonry; compressive strength; clay blocks; FEA; numerical modelling.
Special Issue on: Special Issue by Professor Elio Sacco
An enriched 2D finite element for the nonlinear analysis of masonry walls
by Daniela Addessi, Elio Sacco
The model of Heyman and the statical and kinematical problems for masonry structures
by Maurizio Angelillo
On the analysis of masonry arches
by Nicola Maria Auciello
The spandrel of masonry buildings: experimental tests and numerical analysis
by Bruno Calderoni, Emilia Angela Cordasco, Gaetana Pacella, Paolo Simoniello
Thrust evaluations of masonry domes. An application to the St. Peters Dome
by Mario Como
Seismic vulnerability assessment of churches at regional scale after the 2009 LAquila earthquake
by Gianfranco De Matteis, Giuseppe Brando, Valentina Corlito, Emanuela Criber, Mariateresa Guadagnuolo
On the shape optimization of the force networks of masonry structures
by Giuseppe Rocchetta, Mariella De Piano, Valentino P. Berardi, Fernando Fraternali
Palazzo Ducale in Parete: remarks on code provisions
by Giorgio Frunzio, Luciana Di Gennaro, Mariateresa Guadagnuolo
Some laser-scanner applications in structural analysis
by Claudio Alessandri, Vincenzo Mallardo
Thrust network analysis of masonry vaults
by Francesco Marmo, Daniele Masi, Daniele Mase, Luciano Rosati
Lateral torsional buckling of compressed open thin walled beams: experimental confirmations
by Ida Mascolo, Marcello Fulgione, Mario Pasquino
Wall structure finite-element by BEM coupling
by Vincenzo Minutolo, Eugenio Ruocco