Cyclic shear-compression tests on masonry walls strengthened with alternative configurations of CFRP strips

2016 ◽  
Vol 14 (6) ◽  
pp. 1695-1720 ◽  
Author(s):  
Enzo Martinelli ◽  
Francesco Perri ◽  
Carmen Sguazzo ◽  
Ciro Faella
2021 ◽  
Author(s):  
Lorenzo Scandolo ◽  
Stefano Podestà

Abstract The evaluation of structural safety derives from the knowledge of material properties. In case of existent masonry building, the definition of reliable mechanical parameters could be a very difficult task to be achieved. For this reason, an estimation of these values is useful, for example it is the first phase of the knowledge process, for simplified mechanical model or when NTD test is the only possibility.The transversal connection in masonry panels is a technological detail that affects the static and seismic behavior and could significantly increase the strength of the element.In this paper the effect of transversal connection in double-leaf brickwork masonry panels is evaluated by diagonal compression tests. To achieve this goal, a new set-up was designed to load each leaf independently.The results have shown an increment of about 20% in strength if transversal connection is present. If the leaves have very different mechanical parameters, the tests highlight an unexpected behavior.


2018 ◽  
Vol 9 (3) ◽  
pp. 281-295 ◽  
Author(s):  
Patricia Raposo ◽  
André Furtado ◽  
António Arêde ◽  
Humberto Varum ◽  
Hugo Rodrigues

Purpose The infill masonry walls in recent worldwide earthquakes have shown that it is necessary to conduct further studies to characterize the behavior of existing buildings and, in particular, of infill masonry walls under seismic activity. The lack of characterization studies of infill walls made by concrete blocks justifies the investigation reported herein, which includes experimental tests on sample sets to evaluate the mechanical properties of masonry components (units and mortar) and assemblages (wallets) made with masonry units from Faial. For the later, normal compressive, diagonal tensile/shear and out-of-plane flexural strengths were obtained according to standard procedures, the results of which are presented in the manuscript. The paper aims to discuss these issues. Design/methodology/approach One experimental campaign was conducted with the aim to mechanically characterize concrete blocks masonry samples. Several experimental tests were carried out in full-scale masonry concrete wallets according to the constructive methodology used. Findings Based on the data obtained from the mechanical characterization tests of the concrete masonry blocks, it can be seen that under simple compression, the masonry specimens’ average resistance is about 6 times superior than the average resistance to diagonal shear/tension, while the stiffness is almost doubled. In simple compression tests, it was observed that the masonry specimens cracked in areas of higher drilling of the blocks. In the tensile tests by diagonal compression, it was found that the test specimens were mainly fissured by the block/mortar joint interfaces, following the delineation of settlement and top joints. Originality/value There are no experimental results available in the literature for this type of bricks that can contribute to the development of numerical studies.


2017 ◽  
Vol 747 ◽  
pp. 334-341 ◽  
Author(s):  
Francesca Ferretti ◽  
Andrea Incerti ◽  
Barbara Ferracuti ◽  
Claudio Mazzotti

The use of fiber reinforced composite materials for the retrofitting of existing masonry buildings is investigated in this paper. Indeed, they represent a great alternative to traditional strengthening techniques for the improvement of the seismic performance of masonry walls. Focusing on the in-plane behavior of masonry, an experimental campaign is here presented with the objective of studying the efficiency of different strengthening solutions. Diagonal compression tests were conducted on single-leaf masonry panels reinforced with Fiber Reinforced Cementitious Matrix (FRCM) using different fibers typologies and layouts. Glass or carbon fiber grids embedded in a lime-based mortar matrix were applied on one or both sides of masonry panels, with or without mechanical anchorages. The comparison of the different strengthening techniques is analyzed in terms of failure mode, strength and ductility. The results are then discussed considering the provisions and design formula proposed for FRP strengthening by the Italian CNR Guidelines.


2009 ◽  
Vol 417-418 ◽  
pp. 753-756
Author(s):  
Lucio Nobile ◽  
Cristina Gentilini ◽  
Veronica Bartolomeo ◽  
Mario Bonagura

Several masonry panels are studied by means of destructive tests such as compressive, diagonal compression and shear-compression tests. The experimental research allows to characterize the mechanical properties of masonry walls in order to assess the masonry performance. Moreover, a brief recall of the most important experimental progress is presented in order to understand the state of the art of the research in the field of destructive tests.


Author(s):  
Tinard Violaine ◽  
Nguyen Quang Tam ◽  
Fond Christophe

High damping rubber (HDR) is used in HDR bearings (HDRBs) which are dissipating devices in structural systems. These devices actually have to support permanent static load in compression and potential cyclic shear when earthquakes occur. Mastering the behavior of bearings implies an accurate understanding of HDR response in such configuration. The behavior of HDR is, however, complex due to the nonlinearity and time dependance of stress–strain response and especially Mullins effect. To the authors' knowledge, tests on HDR under combined quasi-static compression and cyclic shear (QC-CS) have not been performed with regard to Mullins effect yet. The purpose of this study is thus to assess experimentally Mullins effect in HDR, especially under QC-CS. In order to achieve this aim, cyclic tensile and compression tests were first carried out to confirm the occurrence of Mullins effect in the considered HDR. Then, an original biaxial setup allowing testing HDR specimen under QC-CS was developed. This setup enables us to identify Mullins effect of the considered HDR under this kind of loading. Tests carried out with this setup were thus widened to the study of the influence of compression stress on shear response under this loading, especially in terms of shear modulus and density of energy dissipation.


2017 ◽  
Vol 747 ◽  
pp. 289-297 ◽  
Author(s):  
Natalino Gattesco ◽  
Ingrid Boem

The results of some diagonal compression tests performed on solid brick masonry samples (1160x1160x250 mm3) to evaluate and compare the effectiveness of different shear reinforcement techniques for existing masonry based of the application, on both sides of the wall, of a mortar coating layer reinforced with fiber composite meshes are presented and discussed in the paper. In particular, 30 mm and 10 mm thick mortar coatings, made of three different mortar types and reinforced by means of both glass and carbon-fibers composite meshes were considered. Significant resistance increases (about 110%) were attained in respect to plain masonry; moreover, it emerged that the meshes are able to prevent the masonry brittle collapse, absorbing tensile stresses in the cracked areas. By maintaining constant the coating thickness, better mortar characteristics determined an increase of the resistance increment ratio but a more rapid decrease of resistance after peak. Similar performances were attained by samples characterized by approximately constant values of shear stiffness and diagonal compression resistance. The differences attributable to the different type of meshes resulted minimal, due to the similar reinforcement percentage.


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