Diagonal compression tests on stone masonry panels: experimental results and analytical interpretations

2016 ◽  
Vol 1 (3) ◽  
pp. 223 ◽  
Author(s):  
Chiara Calderini ◽  
Stefania Degli Abbati
Author(s):  
Enea Mustafaraj ◽  
Yavuz Yardim

In this paper, it is presented the experimental results of a campaign on diagonal compression tests, as of ASTM E519-02, to assess and compare the in-plane behavior of standard size of 1200 × 1200 × 250 mm, for three unreinforced and three reinforced wall panels by glass fiber reinforced polymer (GFRP) embedded in an inorganic matrix.From the diagonal compression test results, were determined some of the main mechanical parameters such as: shear strength, modulus of rigidity and ductility, before and after application of the reinforcement.The experimental results showed that the GFRP reinforced panels exhibited a significant increase of 127% in shear resistance, 1100% in ductility and 650% in modulus of rigidity when compared to unreinforced panels.It was concluded that this technique provided satisfactory results and can be considered a suitable method for repair of masonry structures.


2019 ◽  
Vol 817 ◽  
pp. 552-559
Author(s):  
Francesca Ferretti ◽  
Andrea Incerti ◽  
Anna Rosa Tilocca ◽  
Claudio Mazzotti

During the last decades, several seismic phenomena have shown the high vulnerability of existing stone masonry structures subject to horizontal actions. Innovative composite materials, such as Fiber Reinforced Cementitious Matrix (FRCM), can be adopted for the retrofitting of masonry structures. The use of these innovative FRCM systems is usually combined with a more traditional retrofitting technique: grout injection. It allows to restore or improve the transversal connection between wall leaves, ensuring a monolithic behavior of the structural element. The objective of this research was to analyze the effect of the quality of the grout injection on the shear response of FRCM strengthened stone masonry panels. Results from an experimental campaign, where stone masonry specimens were subject to diagonal compression tests, are therefore presented in this paper. Two samples were subject to grout injection and one of them was strengthened with Steel Reinforced Grout (SRG). Comparisons between the experimental results showed that grout injection alone, if correctly executed, could determine a significant improvement in the shear capacity of masonry panels. The application of the FRCM strengthening system could further enhance the behavior of the samples, especially influencing the failure mode. Comparisons with analytical formulations for the evaluation of the capacity of strengthened walls are also presented.


Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4008
Author(s):  
Zhengkai Feng ◽  
Heng Wang ◽  
Chuanjiang Wang ◽  
Xiujuan Sun ◽  
Shuai Zhang

Fused deposition modeling (FDM) has the advantage of being able to process complex workpieces with relatively simple operations. However, when processing complex components in a suspended state, it is necessary to add support parts to be processed and formed, which indicates an excessive dependence on support. The stress intensity of the supported positions of the printing components can be modified by changing the supporting model of the parts, their density, and their distance in relation to the Z direction in the FDM printing settings. The focus of the present work was to study the influences of these three modified factors on the stress intensity of the supporting position of the printing components. In this study, 99 sets of compression tests were carried out using a position of an FDM-supported part, and the experimental results were observed and analyzed with a 3D topographic imager. A reference experiment on the anti-pressure abilities of the printing components without support was also conducted. The experimental results clarify how the above factors can affect the anti-pressure abilities of the supporting positions of the printing components. According to the results, when the supporting density is 30% and the supporting distance in the Z direction is Z = 0.14, the compressive strength of the printing component is lowest. When the supporting density of the printing component is ≤30% and the supporting distance in the Z direction is Z ≥ 0.10, the compressive strength of printing without support is greater than that of the linear support model. Under the same conditions, the grid-support method offers the highest compressive strength.


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.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Bin Xu ◽  
Xiaoyan Lei ◽  
P. Wang ◽  
Hui Song

There are various definitions of damage variables from the existing damage models. The calculated damage value by the current methods still could not well correspond to the actual damage value. Therefore, it is necessary to establish a damage evolution model corresponding to the actual damage evolution. In this paper, a strain rate-sensitive isotropic damage model for plain concrete is proposed to describe its nonlinear behavior. Cyclic uniaxial compression tests were conducted on concrete samples at three strain rates of 10−3s−1, 10−4s−1, and 10−5s−1, respectively, and ultrasonic wave measurements were made at specified strain values during the loading progress. A damage variable was defined using the secant and initial moduli, and concrete damage evolution was then studied using the experimental results of the cyclic uniaxial compression tests conducted at the different strain rates. A viscoelastic stress-strain relationship, which considered the proposed damage evolution model, was presented according to the principles of irreversible thermodynamics. The model results agreed well with the experiment and indicated that the proposed damage evolution model can accurately characterize the development of macroscopic mechanical weakening of concrete. A damage-coupled viscoelastic constitutive relationship of concrete was recommended. It was concluded that the model could not only characterize the stress-strain response of materials under one-dimensional compressive load but also truly reflect the degradation law of the macromechanical properties of materials. The proposed damage model will advance the understanding of the failure process of concrete materials.


2011 ◽  
Vol 243-249 ◽  
pp. 704-709
Author(s):  
Chun Yi Xu ◽  
Ming Liu ◽  
Bo Xu

To study the influence of slenderness on the compressive bearing capacity of autoclaved fly ash perforated brick masonry long columns and provide experimental evidences for making corresponding technical code, compression tests were conducted on 9 autoclaved fly ash perforated brick masonrys long columns of different slenderness. The damage patterns and compression performance are analyzed. The experimental results indicate that compressive capacity decreases proportionally as slenderness increases and the proposed formula of axial compressive bearing capacity for autoclaved fly ash perforated brick masonry columns is given. The nonlinear FEA program ANSYS is also adopted to simulate the behaviors of masonry columns. By comparing results find that the simulated results agree well with the test ones, the rationality and applicability of the model are verified.


2020 ◽  
Vol 10 (6) ◽  
pp. 1942
Author(s):  
You Xianhui ◽  
Wu Zhaoqi ◽  
Chen Zehao

Grouted connections are commonly used in marine engineering, especially on oil platforms, cross-sea bridges, and offshore wind power turbines. The prediction methods for axial carrying capacity of grouted connections with shear keys and their application ranges in current codes were analyzed in this paper. The calculated results by using different codes were compared based on a practical grouted connection between steel piles and the jacket foundation of a wind turbine. The research team conducted axial compression tests on seven specimens, collected a wide range of experimental results to establish a database, and finally compared the standard calculation results with the experimental results. The study indicates that the axial strength of grouted connections predicted by different methods is distinct. The calculation formula of the British Health and Safety Executive (HSE, 2002) has obvious limitations; specifically, with increased shear keys, strength is overestimated, resulting in insecure design outcome of structures. The results calculated by the Norwegian Det Norske Veritas (DNV, 2013) are generally consistent with the experimental results, in which the reduction effect of multiple shear keys was considered. The prediction method of the American Petroleum Institute (API, 2007), which undervalues the bearing performance of connections, is excessively conservative. The method of the combined Norwegian and German Det Norske Veritas–Germanischer Lloyd (DNV-GL, 2016) has wider applicability and is safe, reliable, and economical.


2020 ◽  
Vol 12 (24) ◽  
pp. 10468
Author(s):  
Muhammad Safdar ◽  
Tim Newson ◽  
Colin Schmidt ◽  
Kenichi Sato ◽  
Takuro Fujikawa ◽  
...  

The disposal of 2011 Japan earthquake waste has become an important issue in Japan and it is not realistic or economical to send all of these wastes to landfill sites, due to limited space, high costs, and related environmental issues. In sustainable geotechnical applications, mixing of the separated soils from disaster wastes with additives (e.g., cement and fiber) is required to improve their strength and stiffness characteristics. In this study, monotonic triaxial drained compression tests are performed on medium dense specimens of Toyoura sand-cement-fiber mixtures with different percentages of fiber and cement (e.g., 0–3%) additives. The experimental results indicate that behavior of the mixtures is significantly affected by the concentration of fiber and cement additives. Based on a comprehensive set of test results, modifications to the series of equations were developed that can be used to evaluate the shear modulus and mobilized stress curves at small-strain levels. The experimental results and model comparison show that the elastic threshold strain (γe), reference strain (γr), increases with fiber and cement additives. In addition, the range of curvature parameter, from 0.88 to 1.0, provides a good comparison with the results of small-strain measurements. Overall, the comparison of the results and model shows that the small-strain measurements obtained using local strain transducers fall within the range of model upper and lower bound curves. The results of the unreinforced, fiber, and cemented sand shows a close agreement with the model mean curve, but fiber-reinforced cemented sand shows a good comparison with model upper bound.


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.


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