Marie-José Nollet, Professor, Department of Construction Engineering, École de technologie supérieure, 1100 Notre-Dame St. W., Montreal, QC, Canada, marie-jose.nollet@etsmtl.ca
Ahmad Abo El Ezz, Post-Doctoral Fellow, Department of Construction Engineering, École de technologie supérieure, 1100 NotreDame St. W., Montreal, QC, Canada, ahmad.abo-el-ezz.1@ens.etsmtl.ca
Pascal Moretti ,Master student, Department of Construction Engineering, École de technologie supérieure, 1100 Notre-Dame St. W., Montreal, QC, Canada, pascal.moretti.1@ens.etsmtl.ca and eric.boldireff.1@ens.etsmtl.ca

ABSTRACT
In Eastern Canada, seismic vulnerability analysis of unreinforced stone masonry buildings relies on analytical methods consisting of structural modeling and evaluation of the likelihood for a given building to experience damage from earthquake of a given intensity. In this paper, the main components of a vulnerability assessment procedure are reviewed with emphasis on the significance of masonry mechanical properties on damage estimates. An experimental program is presented which was developed to assess mechanical properties of typical stone masonry assemblies composed of lime-stone blocks joined with cement/lime mortar commonly used in heritage buildings construction in Eastern Canada. The experimental joint shear bond, compressive and diagonal shear strength parameters were used to develop seismic vulnerability functions expressed as function of the mean damage factor (MDF) corresponding to the expected repair cost ratio for increasing seismic intensity measure (IM=Sa0.3sec). The influence of the mechanical properties on damage assessment is evaluated. The results provided a quantitative assessment of the impacts of mechanical properties on the predicted seismic induced repair costs for stone masonry buildings. This has a direct impact on the decisions of risk assessment studies for seismic mitigation and retrofit that are related to the expected repair costs for the corresponding site-specific seismic hazard intensity.

190

Antonio Incera, Dipl.-Ing., Universidad Latina de Costa Rica, Civil Engineering Department, Heredia, Costa Rica
Andrés Reyes,Professor and researcher Universidad Latina de Costa Rica, Civil Engineering Department, Heredia; Design Engineer, Productos de Concreto S.A, Engineering Department, Alajuela, Costa Rica, andres.reyes@pc.cr
Minor Murillo, Professor Universidad Latina de Costa Rica, Civil Engineering Department, Heredia; Department Head, Productos de Concreto S.A, Research and Development Department, Alajuela, Costa Rica minor.murillo@pc.cr

ABSTRACT
Given the current complementary requirements for structural masonry and the growth of the industry in Costa Rica, the need has arisen to implement production processes that allow to obtain
improvements in the resistance to the compression of concrete blocks without the necessity of incurring in large economic changes. As a result of this, the task of analyzing the effect of curing in concrete blocks with dry mixtures has been given by the experimental proposal of 13 methods of curing in the laboratory, by testing a batch of 5 blocks to 24 hours, 8 and 28 days. From the implemented systems, a comparison was made between pieces without any cure and others exposed to a method assigned as the “ideal”. The proposed systems were determined considering the weather, the manufacture site characteristics, economic feasibility, place and accessibility to the materials. Finally, a comparative table of the methods with greater projection and practicality in its application at industrial level, is made. With the results obtained, it is possible to determine the importance of cure at early ages in concrete blocks with dry mixtures, including the methods of ease application at industrial level, considering the percentage in strength increase due to the correct application in the curing times.

189

Setare Seyedain Boroujeni,  Graduate Student, Department of Civil Engineering, Schulich School of Engineering, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada, setare.seyedain@gmail.com
Nigel Shrive, Professor, Department of Civil Engineering, Schulich School of Engineering, University of Calgary, 2500 University  Drive NW, Calgary, AB, Canada, ngshrive@ucalgary.ca.

ABSTRACT
Despite the high level of vulnerability of unreinforced masonry structures under applied loads and the importance of their reliability evaluation, there is no formal methodology to assess the reliability of historic masonry structures. Therefore, a step-by-step methodology for assessing the reliability level of historic masonry structures is being developed. To develop an appropriate determinate methodology, estimations of probabilistic models of structural resistance and load effects are required to formulate a limit state function. The stochastic characteristics of construction materials play key roles in the determination of probabilistic models of structural resistance. Codes of practice recommend values as well as the best fit distributions for different material characteristics. As codes are necessarily conservative and are also generally aimed at design or assessment with modern masonry materials, the use of code values for historical structures may lead to inaccurate reliability assessment. Destructive testing of a historic masonry structure or its components in order to get more realistic information regarding the material properties is not recommended as such tests may lead to irreparable damage to these valuable structures. Thus methodologies for estimating the statistical characteristics of historic masonry materials through non-destructive tests as well as suitable probabilistic models are described. Best fit probabilistic models for different load effects are also presented. Finally, target reliability index and failure probability values and different approaches for calculating suitable targets for historic structures are described. Evaluation of the reliability level of historical structures through the recommended procedure would lead to more realistic and accurate levels of reliability estimation without requiring degradation of the historic structure.

188

Alex Brodsky, PhD student, Faculty of Civil and Environmental Engineering, Technion Israel Institute of Technology, Haifa 32000, Israel, brod@technion.ac.il
Oded Rabinovitch, Professor, Abel Wolman Chair in Civil Engineering, Faculty of Civil and Environmental Engineering, Technion Israel Institute of Technology, Haifa 32000, Israel, cvoded@technion.ac.il
David Z. Yankelevsky, Professor Emeritus, Faculty of Civil and Environmental Engineering, Technion Israel Institute of Technology, Haifa 32000, Israel, davidyri@technion.ac.il

ABSTRACT
The interaction of unreinforced masonry infill walls with the surrounding frame is the key mechanism for the composite action of the structural element. This interaction is of importance under all types of loads but it is especially important under extreme loads such as earthquakes, vehicle impact, blast action etc. Due to the complex interaction and the resulting lack of knowledge regarding the composite action of the infill wall and the frame, the masonry infill wall is commonly considered in the structural design through oversimplified methods. Nevertheless, the interaction loads affect the infill wall behaviour and at the same time, they affect the failure mode of the frame. Therefore, it is crucial to characterize, understand, and evaluate this interaction and to establish models that can quantify the composite behaviour and assess the failure mechanism and the capacity of the composite system. Achieving these goals can improve the design tools for new buildings, enhance the assessment methods of existing buildings, and enable the development of advanced computational models. Aiming at these goals, this paper looks into the complex interaction phenomenon. The paper adopts an experimental methodology and an experimental setup that includes a masonry infill wall surrounded by a steel frame is used as the main experimental platform. The new experimental apparatus provides unique parameters of the interaction including the detection of the contact zone between the masonry wall and the frame and the assessment of the magnitude and its distribution of the contact tractions. This paper aims at describing the above and a few of the new findings.

185

Alex Brodsky, PhD student, Faculty of Civil and Environmental Engineering, Technion Israel Institute of Technology, Haifa 32000, Israel, brod@technion.ac.il
Oded Rabinovitch, Professor, Abel Wolman Chair in Civil Engineering, Faculty of Civil and Environmental Engineering, Technion Israel Institute of Technology, Haifa 32000, Israel, cvoded@technion.ac.il
David Z. Yankelevsky, Professor Emeritus, Faculty of Civil and Environmental Engineering, Technion Israel Institute of Technology, Haifa 32000, Israel, davidyri@technion.ac.il

ABSTRACT
The in plane behavior of masonry infill walls that are subjected to lateral loading simulating the effects of earthquakes on buildings has been the subject of many studies. The present work is focused on a problem that has been hardly studied and refers to the vertical action on such walls. In particular, it concerns a vertical action that evolves when a supporting column of a multi-story reinforced concrete frame with infill masonry walls fails. Such failure may happen as a result of extreme loadings for instance a strong earthquake, car impact, or military or terror action in proximity to the column. Without infill walls, the loss of a supporting column may lead to a partial or even full progressive collapse of the bare reinforced concrete frames. The presence of masonry infill walls may restrain the process and even prevent the development of a progressive collapse mechanism. The aim of this study is to look into the role of the composite action of a frame and an infill wall in the event of loss of a supporting column. The study adopts an experimental methodology and numerical methods aiming to evaluate the contributions of the unreinforced masonry infill, to examine its interaction with the frame, and to quantify its contribution to the resistance of the bare frame under such circumstances.

184

Giulio Castori, Researcher, Dept. of Engineering, Perugia University, Via Duranti, 92 06125 Perugia, Italy giulio.castori@unipg.it
Antonio Borri, Professor, Dept. of Engineering, Perugia University, Via Duranti, 92 06125 Perugia, Italy antonio.borri@unipg.it
Marco Corradi,  Associate Professor, Dept. of Mechanical & Construction Engineering, Northumbria University, Wynne-Jones Building, NE1 8ST Newcastle Upon Tyne, United Kingdom, marco.corradi@northumbria.ac.uk, and Dept. of Engineering, Perugia University, Via Duranti, 92 06125 Perugia, Italy marco.corradi@unipg.it
Righetti Luca, PhD candidate, Dept. of Mechanical & Construction Engineering, Northumbria University, Wynne-Jones Building, NE1 8ST Newcastle Upon Tyne, United Kingdom, luca.righetti@northumbria.ac.uk

ABSTRACT
Over the last fifteen years, new techniques and materials have been used to retrofit masonry structures for improved seismic performance as well as a variety of other strengthening applications. The global behavior of a stone masonry wall is often governed by the level of connection between masonry leaves and the overall quality of the masonry material (mortar, block and arrangement). This paper presents the results of an investigation carried out on multi leaf stone masonry panels retrofitted using stainless steel rod inserted in a grouted fabric sleeve. The paper also reports the results of a non-linear numerical investigation calibrated using laboratory tests. Several wall panels were assembled in the laboratory using solid calcareous stones and weak mortar and the effectiveness of the connectors was tested in shear and compression on both virgin and damaged wall panels. Experimental results show that a substantial improvement of the panels’ mechanical behavior can be achieved by applying transverse connectors. The feasibility of using the 3-Dimensional (3D) finite element model to analyze multi-leaf walls reinforced with transverse connectors is examined by comparing the  model to experimental data.

183

Emanuel Jannasch, Senior Instructor, Dalhousie University School of Architecture, 5410 Spring Garden Road, Halifax, NS, Canada, jannasch@dal.ca

ABSTRACT
The author and his students have built several counter-intuitive and in some cases unprecedented masonry domes. Forms include the anticlastic or bell-shaped pseudomes and antidomes that descend from their foundation ring to form a basin. An ambidome, which rises in the normal manner but descends to a pendant oculus, is shown in Figure 1. The domes are all unreinforced and un-mortared masonry, and un-bound except by a tensile foundation ring. The completely flat floordomes achieve span-to-depth ratios up to 27:1. Some are made of voussoirs that taper upward rather than down. Yet all the structures are built of loose blocks held in place by gravity alone. Our experiments to date are small in scale, but no matter how unbelievable they appear in cross section, physical demonstration of their inherent stability is incontrovertible. None of the domes are understandable as arches rotated about a vertical axis, but seen as vertical stacks of fully circular horizontal arches they begin to make sense. This conceptualization emphasizes the hoop compression that pre-stresses and stabilizes extant shallow domes, and reminds us of the horizontal and vertical shear forces that act throughout all “compression-only” domes and arches. Some of the forms look more useful than others, but all of them are instructive. They show that our funicular conception of domes is incomplete, and suggest ways of broadening our perspective. Whether unreinforced masonry is valued for social or environmental sustainability or to avoid rust-driven failures, any improvements to masonry theory should be of value.

182

Arturo E. Schultz, Prof., Dept. of Civil, Envir., and Geo- Engrg., Univ. of Minnesota, Minneapolis, USA, 55455, schul088@umn.edu

ABSTRACT
On 16 April 2016, a magnitude (Mw) 7.8 earthquake struck coastal Ecuador and generated over 100 aftershocks (Mw ≥ 6). The epicenter of the main shock was approximately 29 km southsoutheast of Muisne, and had intensities of VIII and IX over a large affected region in the provinces of Esmeraldas and Manabí. More than 10,500 buildings were damaged or collapsed in urban areas, and more 8,100 in rural areas. The affected buildings were primarily concentrated in the municipalities of Bahía de Caráquez, Calceta, Canoa, Chone, Manta, Muisne, Pedernales, and Portoviejo. This paper documents observations made by the author as part of a reconnaissance team that visited the affected sites. Most of the buildings observed were reinforced concrete frames with unreinforced masonry infill and partitions. Extensive nonstructural damage was observed in the masonry of both engineered and non-engineered buildings, and structural damage was also common in the RC frames. Observations on the damage patterns are presented, as well as trends associated with the URM panels.

181

Md Akhtar Hossain, PhD Student, Centre for Infrastructure Performance and Reliability, The University of Newcastle, Australia, Md.Akhtar.Hossain@uon.edu.au
Yuri Zarevich Totoev, Senior Lecturer, Centre for Infrastructure Performance and Reliability, The University of Newcastle, Australia, Yuri.Totoev@newcastle.edu.au
Mark J. Masia, Associate Professor, Centre for Infrastructure Performance and Reliability, The University of Newcastle, Australia, Mark.Masia@newcastle.edu.au
Mark Friend, Undergraduate Student, Centre for Infrastructure Performance and Reliability, The University of Newcastle, Australia, Mark.Friend@uon.edu.au

ABSTRACT
An innovative masonry building system is being developed in the Centre for Infrastructure Performance and Reliability at The University of Newcastle, Australia. It consists of mortar-less masonry infill panels made of semi-interlocking masonry (SIM) units capable of relative slidingin-plane of a panel and interlocked to prevent sliding out-of-plane of a panel. This new system attempts to improve the earthquake performance of the framed structure by increasing the displacement ductility and the energy dissipation capacity of infill panels. A special steel testing frame with the pin connections was built to test SIM panels. The arrangement with pin connection allows application of storey drift up to 6%. Digital Image Correlation (DIC) technique is used to record the displacement behavior of the masonry panel. This paper presents the results of an experimental testing programme on SIM panels subject to cyclic in-plane lateral displacement. The primary aim of this experimental program is to obtain force-displacement relationships for SIM panel and to understand structural as well as the mechanical failure mode of the system.

179

René Mazur, Research Assistant, Institute of Concrete and Masonry Structures, Technische Universität Darmstadt, FranziskaBraun-Straße 3, 64287 Darmstadt, Germany, mazur@massivbau.tu-darmstadt.de
Carl-Alexander Graubner, Professor, Institute of Concrete and Masonry Structures, Technische Universität Darmstadt, Franziska-Braun-Straße m 3, 64287 Darmstadt, Germany, graubner@massivbau.tu-darmstadt.de

ABSTRACT
Unreinforced masonry walls are very well suited to carry vertical loads. In addition, out-of-plane bending moments caused by horizontal loads such as wind or eccentrically applied loads of slabs may occur and have to be taken into account. Since masonry structures according to the European standard Eurocode 6 do not have any computational tensile strength, no bending moments can be carried by a cross section without an existing normal force. That means that the bending capacity depends on the acting normal force. Therefore, a change of the existing vertical loads always results in a change of the horizontal resistance of the structure and vice versa. This paper deals with simplified design procedures in which the influence of the acting bending moment is already integrated in the dimensioning equations of the resistance side. Hence, it is sufficient to compare the acting and the resisting normal force in order to prove the maximum carrying capacity of a wall without considering the bending stress directly. There are also simplified calculation methods dealing with masonry walls under horizontal wind or soil pressure with low vertical load. In this case, a minimum required vertical load has to be determined to resist the acting bending moment. A current research project compares the results of the simplified design methods with a more precise calculation and identifies the boundary conditions for proving that the simplified design methods lead to results on the safe side. Additionally, an investigation of the criteria for using the simplified calculation methods considering an extension on higher walls and longer slab spans was carried out. In this paper the technical background, the results and the restrictions of such simplified design methods will be demonstrated.

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