scholarly journals Out-of-plane instability of reinforced masonry uniaxial specimens under reversed cyclic axial loading

2017 ◽  
Vol 44 (5) ◽  
pp. 367-376 ◽  
Author(s):  
Nazli Azimikor ◽  
Svetlana Brzev ◽  
Kenneth J. Elwood ◽  
Donald L. Anderson ◽  
William McEwen
Keyword(s):  
Axial Loading ◽  
Shear Walls ◽  
Reinforcement Ratio ◽  
Design Parameters ◽  
Key Factors ◽  
Cyclic Tension ◽  
Reinforced Masonry ◽  
Out Of Plane ◽  
Tension And Compression ◽  
Reversed Cyclic

Results of a study performed on the out-of-plane instability of reinforced masonry shear walls (RMSW) under seismic loading are presented. The study was conducted to gain understanding of the out-of-plane instability mechanism and the key factors influencing its development through the testing of five reinforced masonry uniaxial specimens under reversed cyclic tension and compression. The specimens represented the end zone of a RMSW. The design parameters considered in the study included longitudinal reinforcement ratio and height-to-thickness ratio for the test specimens. It was found that onset of out-of-plane instability is strongly influenced by the level of tensile strains developed in the specimens, the reinforcement ratio, and the bar size. In this case, out-of-plane instability occurred when out-of-plane displacements exceeded the critical value equal to half the wall thickness. A study on full-scale RMSW specimens subjected to reversed cyclic loading, also undertaken under this research program, is expected to verify the findings of this study and contribute towards development of design criteria for out-of-plane stability of RMSW.

Detailed micro-modeling of partially grouted reinforced masonry shear walls: extended validation and parametric study

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Sebastián Calderón ◽  
Cristián Sandoval ◽  
Gabriele Milani ◽  
Oriol Arnau
Keyword(s):  
Shear Strength ◽  
Aspect Ratio ◽  
Parametric Study ◽  
Shear Walls ◽  
Lateral Force ◽  
Reinforcement Ratio ◽  
Design Parameters ◽  
Compression Stress ◽  
Reinforced Masonry ◽  
Micro Modeling

AbstractPartially grouted reinforced masonry (PG-RM) shear walls have been widely used as structural elements in low- and medium-rise earthquake-resistant buildings. Nonetheless, assessing its shear strength represents a complex task mainly because the partial grouting provides a non-constant cross section, which results in heterogeneous stress–strain patterns. Consequently, refined modeling techniques are needed to reproduce local failure mechanisms taking place in these walls, which significantly influence the global response. In response to this issue, a detailed micro-modeling approach based on the finite element method was proposed in previous studies by the authors. Although the numerical strategy provided accurate results, further validation is required. Therefore, in this study, the experimental results of seven PG-RM shear walls of multi-perforated clay bricks with bed-joint reinforcement are employed as validation cases. These seven walls presented variations in five design parameters. The validated numerical model was then employed to perform a parametric study to assess the influence of the wall aspect ratio, axial pre-compression stress, and horizontal reinforcement ratio on the in-plane lateral behavior of PG-RM shear walls. The obtained results show that the three studied design parameters modified the crack patterns of the walls. Besides, increasing the axial pre-compression stress or reducing the aspect ratio resulted in higher walls’ shear strength. Additionally, decreasing the horizontal reinforcement ratio or increasing the aspect ratio generated a higher story-drift ratio at maximum lateral force. Finally, it was corroborated that the positive effect of the axial pre-compression stress on the walls’ shear strength decreases inversely proportional to the aspect ratio.

Estimation of Seismic Energy Dissipation for Steel Slit Shear Walls Considering Out-of-Plane Buckling

2021 ◽  
Author(s):  
Yiming Ma ◽  
Liusheng He ◽  
Ming Li
Keyword(s):  
Energy Dissipation ◽  
Shear Walls ◽  
Seismic Energy ◽  
Thickness Ratio ◽  
Design Parameters ◽  
Test Results ◽  
Loading Test ◽  
Aspect Ratios ◽  
Out Of Plane ◽  
Energy Dissipation Capacity

Steel slit shear walls (SSSWs), made by cutting slits in steel plates, are increasingly adopted in seismic design of buildings for energy dissipation. This paper estimates the seismic energy dissipation capacity of SSSWs considering out-of-plane buckling. In the experimental study, three SSSW specimens were designed with different width-thickness ratios and aspect ratios and tested under quasi-static cyclic loading. Test results showed that the width-thickness ratio of the links dominated the occurrence of out-of-plane buckling, which produced pinching in the hysteresis and thus reduced the energy dissipation capacity. Out-of-plane buckling occurred earlier for the links with a larger width-thickness ratio, and vice versa. Refined finite element model was built for the SSSW specimens, and validated by the test results. The concept of average pinching parameter was proposed to quantify the degree of pinching in the hysteresis. Through the parametric analysis, an equation was derived to estimate the average pinching parameter of the SSSWs with different design parameters. A new method for estimating the energy dissipation of the SSSWs considering out-of-plane buckling was proposed, by which the predicted energy dissipation agreed well with the test results.

Out-of-Plane Performance of Reinforced Masonry Shear Walls Constructed with Boundary Elements

2019 ◽  
Vol 145 (8) ◽  
pp. 04019073 ◽  
Author(s):  
Tarek El-Hashimy ◽  
Mohamed Ezzeldin ◽  
Michael Tait ◽  
Wael El-Dakhakhni
Keyword(s):  
Shear Walls ◽  
Boundary Elements ◽  
Reinforced Masonry ◽  
Out Of Plane

Out-of-Plane Behavior of Load-Bearing Reinforced Masonry Shear Walls

2019 ◽  
Vol 145 (11) ◽  
pp. 04019127 ◽  
Author(s):  
Shady Salem ◽  
Mohamed Ezzeldin ◽  
Wael El-Dakhakhni ◽  
Michael Tait
Keyword(s):  
Shear Walls ◽  
Load Bearing ◽  
Reinforced Masonry ◽  
Out Of Plane

Out-of-Plane Behavior of Slender Reinforced Masonry Shear Walls under In-Plane Loading: Experimental Investigation

2018 ◽  
Vol 144 (3) ◽  
pp. 04018008 ◽  
Author(s):  
B. R. Robazza ◽  
S. Brzev ◽  
T. Y. Yang ◽  
K. J. Elwood ◽  
D. L. Anderson ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Shear Walls ◽  
Reinforced Masonry ◽  
Out Of Plane

scholarly journals Experimental Investigation into the Seismic Performance of Prefabricated Reinforced Masonry Shear Walls with Vertical Joint Connections

2021 ◽  
Vol 11 (10) ◽  
pp. 4421
Author(s):  
Zhiming Zhang ◽  
Fenglai Wang
Keyword(s):  
Seismic Performance ◽  
Cross Sections ◽  
Shear Walls ◽  
Construction Method ◽  
Shear Capacity ◽  
Initial Stiffness ◽  
Equivalent Viscous Damping ◽  
Displacement Ductility ◽  
Reinforced Masonry ◽  
Cracking Performance

In this study, four single-story reinforced masonry shear walls (RMSWs) (two prefabricated and two cast-in-place) under reversed cyclic loading were tested to evaluate their seismic performance. The aim of the study was to evaluate the shear behavior of RMSWs with flanges at the wall ends as well as the effect of construction method. The test results showed that all specimens had a similar failure mode with diagonal cracking. However, the crack distribution was strongly influenced by the construction method. The lateral capacity of the prefabricated walls was 12% and 27% higher than that of the corresponding cast-in-place walls with respect to the rectangular and T-shaped cross sections. The prefabricated walls showed better post-cracking performance than did the cast-in-place wall. The secant stiffness of all the walls decreased rapidly to approximately 63% of the initial stiffness when the first major diagonal crack was observed. The idealized equivalent elastic-plastic system showed that the prefabricated walls had a greater displacement ductility of 3.2–4.8 than that of the cast-in-place walls with a displacement ductility value of 2.3–2.7. This proved that the vertical joints in prefabricated RMSWs enhanced the seismic performance of walls in shear capacity and ductility. In addition, the equivalent viscous damping of the specimens ranged from 0.13 to 0.26 for prefabricated and cast-in-place walls, respectively.

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