International Journal of Masonry Research and Innovation (10 papers in press)
Dynamic modelling structure of hinge-controlled masonry arches and 2D accelerations
by Gabriel Stockdale, Gabriele Milani, Vasilis Sarhosis
Abstract: Engineering efficiency is paramount for the introduction of novel systems and formats of analysis. This work extends an accessible and efficient analysis platform by combining the kinematic equilibrium approach of limit analysis with the single degree of freedom nature of a hinge-controlled masonry arch to perform dynamic modelling of applied two-dimensional acceleration vectors. Utilising ideal conditions, minimum work-paths are formulated to describe the work required to drive the arch to collapse. Then, assuming conservative work allows the formation of a spatial description of kinetic energy, and ultimately the establishment of the time domain for constant 2D accelerations. A dynamic time incremental analysis structure is then formulated based upon the assumption of constant acceleration for each time
step. This dynamic model propagates the centroid displacement and kinetic energy through an applied acceleration sequence. Lastly, the dynamic model under ideal conditions is tested for validity through half-cycle collapse domain benchmark and the conservation of energy.
Keywords: near-real time analysis; dynamic analysis; kinematic collapse load calculator; KCLC; seismic analysis; masonry arch.
Critical analysis of the use of international codes and standards to design Brazilian structural masonry in fire situation
by Wallison Angelim Medeiros, Guilherme A. Parsekian, Armando Lopes Moreno Jr.
Abstract: In Brazil, structural masonry is widely used in the construction of tall buildings. As the country does not have its own standard for masonry in a fire situation, the Fire Department recommends that the design of masonry structures in a fire situation be carried out in accordance with the instructions of Eurocode or similar international standard. This article critically analyses the adoption of design procedures in use in the USA, Australia and Europe for a typical Brazilian masonry structure, verifying the applicability of these codes and taking into account the differences in aggregates used in blocks and finishes, aiming to support discussions on Brazilian standardisation, in addition to comparing the different ways of approaching each standard. The results showed that it is possible to use international codes, but their use will not always portray the real situation, requiring the sector and the technical-scientific community urgently unite to address this issue.
Keywords: masonry; structures; design; fire; standards; codes; tall buildings; standardisation; fire situation; Brazil.
The out-of-plane capacity of semi-interlocking masonry infill panels: experimental and numerical investigations using DIANA and ABAQUS software
by Orod Zarrin, Soheil Dadras Eslamlou, Yuri Z. Totoev, Mark J. Masia
Abstract: The semi interlocking masonry (SIM) system has been developed by the Masonry Research Group at The University of Newcastle, Australia. The main purpose of this system is to enhance the seismic resistance of framed structures with masonry infill panels. In this system, SIM panels dissipate energy during earthquake excitation through the friction on sliding joints between courses of units. A joint project is performed including a series of in-plane and out-of-plane testing programs to evaluate the capacity of SIM panels. The study reported in this paper experimentally investigated the out-of-plane displacement/load capacity of the SIM panel damaged in previous in-plane tests. The experimental results of a full-scale SIM panel made of SIM units with topological and mechanical interlocking units are presented in this
paper. The panel is 1,980 mm and 2,025 mm in length and height, respectively. The thickness of the panel is 110 mm with full contact to the frame. The paper also presents the numerical 3D micro modelling of the tested panel using general nonlinear static analysis in two software programs, namely DIANA FEA and ABAQUS. The out-of-plane load and the displaced shapes of the panel are recorded at regular increments and are compared to the numerical results for verification of the numerical models. The results show that the SIM panels have significant out-of- plane load and displacement capacity.
Keywords: semi-interlocking masonry; SIM; out-of-plane capacity; earthquake resistant; sliding joints; mortar-less.
Investigation of brick alignment effect on compressive strength
by Usman Akmal, Nauman Khurram, Muhammad Ammar, Zahid A. Siddiqi, Tauqir Ahmed
Abstract: Bricks are widely used in construction due to its availability in abundance. As per prevailing standards, compressive strength of brick is determined by placing it in horizontal (bed-wise) orientation. Due to high end-platen effect, the brick strength is overestimated. In this case, peak load corresponding to first visible appearance of crack is considered as failure load. In order to overcome this, an extensive testing is carried out to explore the effect of brick alignment on its compressive strength. Further, a relationship is also proposed between the compressive strength of bricks tested in vertical direction and tested in horizontal direction. It is also proposed to test the brick in vertical direction for more realistic compressive strength value. Moreover, a correction factor of 1.3 is proposed to classify the bricks on the base of their strength obtained in vertical direction.
Keywords: end platen effect; brick masonry; compressive strength; brick alignment.
DEM analysis of the effect of bond pattern on the load bearing capacity of barrel vaults under vertical loads
by Shipeng Chen, Angela Ferrante, Francesco Clementi, Katalin Bagi
Abstract: Bond patterns influence responses of masonry barrel vaults to mechanical loads. In this research, the discrete element method (DEM) was applied to investigate how bond patterns affect the static load bearing capacity of barrel vaults under vertical loads. The two most widely-used bond patterns (transverse and longitudinal) were studied. Using a commercial DEM software, 3DEC, vaults with different angles of embrace were prepared according to both patterns, and then loaded in three alternative ways until failure. The failure loads were recorded, and compared for the two alternative patterns of each overall geometry. Two competing effects were found: 1) in transversal vaults the arches work nearly independently of each other which decreases the load resistance in comparison to longitudinal vaults; 2) larger size of the voussoirs along the arch direction increases the load bearing.
Keywords: masonry; construction; 3DEC; load bearing capacity; size effect.
Special Issue on: Simple Mechanical Models for Unreinforced Historic Masonry Constructions
Experimental and numerical analysis of a scaled dry-joint arch on moving supports
by Chiara Ferrero, Michela Rossi, Pere Roca, Chiara Calderini
Abstract: This paper aims to investigate the response of a scaled segmental dry-joint masonry arch to the settlement of one support. An experimental test and numerical simulations were performed by applying incremental vertical displacements at the right support up to collapse. The experimental test was carried out on a 1:10 small-scale model of the arch made of bi-component composite blocks with dry joints. Numerical simulations were performed using a finite element (FE) micro-modelling approach, where the arch was discretised as a set of very stiff voussoirs connected by nonlinear interfaces. Experimental and numerical results were compared in terms of displacement capacity and collapse mechanisms. The sensitivity of the numerical results to the interface stiffness was also evaluated.
Keywords: masonry arches; experimental tests; FE micro-modelling; support displacements; collapse mechanisms; rigid blocks.
Analytical modelling for the seismic assessment of pointed arches supported by buttresses
by Giuseppe Brandonisio, Antonello De Luca
Abstract: The seismic behaviour of arches is investigated to provide a contribution to the stability of arches with a pointed shape supported by buttresses. The limit analysis (LA) for masonry structures has been herein implemented in analytical modelling based on the use of nonlinear programming techniques for investigating the potential failure mechanisms associated with pointed arches under horizontal forces. A critical assessment of the positioning of hinges over the arch embrace is conducted here. This will allow for a better prediction of the capacity of these structures under seismic actions. The lateral action, which activates the investigated failure mechanisms, is also computed by implementing this new analytical model. This is assessed both in terms of horizontal loading multiplier and associated ground
accelerations. Furthermore, by comparing numerical results derived from scientific literature, it was possible to validate the reliability of the here presented analytical model.
Keywords: masonry; pointed arches; pier walls; limit analysis; seismic assessment; analytical modelling.
P-Bezier energy optimisation for elastic solutions of masonry-like panels
by Antonio Fortunato, Antonio Gesualdo, Ida Mascolo, Michela Monaco
Abstract: The equilibrium problem for masonry-like materials in the Heyman sense can be formulated looking for a minimum of the complementary energy functional defined in the field of admissible stress tensors, belonging to the class of negative semi-definite tensors. The classical mixed boundary problem for a masonry panel is developed assuming that the stress is uniaxial so it is possible to express the complementary energy as a function of the slope of compressive rays which characterise the uniaxiality of the stress field. In this work, a family of proximity curves defined starting from a Bezier curve with three control points to model the slope function is employed. Two structural cases are solved, pure shear displacements and shear-flexural-tensile ones, showing the usefulness of the method when applied to the analysis of masonry piers.
Keywords: masonry panel; mixed boundary problem; complementary energy; energy optimisation; proximity curves; P-Bézier curves.
Structural analysis of historical masonry churches: the case study of S. Giuseppe delle Scalze (Naples, Italy)
by Giancarlo Ramaglia, Gian Piero Lignola, Francesco Fabbrocino, Andrea Prota
Abstract: Structural analysis represents a valid tool to evaluate the seismic capacity of existing structures and to plan retrofit strategies. Howsoever, structural modelling performed on existing masonry buildings could become very complex. This issue increases when the interest focuses on heritage buildings due to the strong heterogeneities that characterise them. This study focuses on the analysis of a religious masonry building: the case study of S. Giuseppe delle Scalze in Naples (Italy). The structure is characterised by a clear deterioration and several damages. Various modelling approaches have been carried out to estimate the main structural behaviour of the church. Starting from surveys, a finite element (FE) model was developed. According to a limited knowledge level, various structural models have been developed, to take into account many variables. Starting from these numerical models, several analyses have been performed: static gravitational, linear dynamic and linear time history analyses. The goal of the analyses is to assess the main sources of damage by comparing the peak stresses with the current damage.
Given the linear-elastic assumption due to the limited knowledge level, the results are useful to assess triggering of damage only.
Keywords: heritage masonry; churches; numerical modelling; seismic damage; Italy.
A new membrane equilibrium solution for masonry railway bridges: the case study of Marsh Lane Bridge
by Carlo Olivieri, Antonio Fortunato, Matthew DeJong
Abstract: Masonry railways bridges were built and are still in use all over Europe and in many other countries all over the world. Limit analysis is widely adopted to assess the equilibrium of these structures under self and train loads and, mainly, assuming uniaxial stresses only in the span direction. In the last decade, some of these bridges, as our case study, have been subjected to detailed structural health monitoring (SHM) campaigns whose primary outcome is that these structures exhibit biaxial stresses. In this paper, within the framework of the Heyman masonry unilateral model, an application of membrane equilibrium analysis (MEA) is presented. MEA provides an efficient approach to account for biaxial stress states and, thus, taking into account beneficial 3D effects for load capacity analyses. This paper illustrates how various assumptions of the membrane behaviour yield a range of potential equilibrium solutions, all of which demonstrate higher capacity than the traditional 2D assessment methods.
Keywords: masonry; membrane equilibrium analysis; MEA; historic structures; railway bridges; structural health monitoring; SHM.