Experimental Study on Seismic Strengthening of Confined Masonry Walls Using RPC

Masonry structures without effective reinforcement are vulnerable to seismic excitation. An innovative strengthening technique was proposed for damaged and undamaged masonry walls. Six confined masonry units with two aspect ratios were tested under in-plane lateral cyclic loading, which consisted of two control walls, two original walls strengthened with reactive powder concrete (RPC-1), and two damaged walls repaired with RPC (RPC-2). The results of the specimens retrofitted with RPC demonstrated that the proposed technique significantly enhanced the seismic performance of masonry walls in terms of lateral strength, ductility, and energy dissipation. Furthermore, the two repaired specimens had a better distributed cracking pattern than the two strengthened specimens. The analysis of the results leads to a better understanding of the effect and mechanism of RPC seismic retrofitting for confined masonry walls.

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Out-of-plane behavior of confined masonry walls with aspect ratios greater than one

Canadian Journal of Civil Engineering ◽

10.1139/cjce-2019-0453 ◽

2021 ◽

Vol 48 (1) ◽

pp. 89-97

Author(s):

Jorge Varela-Rivera ◽

Joel Moreno-Herrera ◽

Luis Fernandez-Baqueiro ◽

Juan Cacep-Rodriguez ◽

Cesar Freyre-Pinto

Keyword(s):

Experimental Study ◽

Aspect Ratio ◽

Compressive Stress ◽

Masonry Walls ◽

Confined Masonry ◽

Aspect Ratios ◽

Out Of Plane ◽

Axial Compressive Stress ◽

Compressive Strut ◽

Failure Line

An experimental study on the out-of-plane behavior of confined masonry walls is presented. Four confined walls with aspect ratios greater than one were tested in the laboratory. Walls were subjected to combined axial and out-of-plane uniform loads. The variables studied were the aspect ratio and the axial compressive stress of walls. It was observed that the out-of-plane strength of walls increased as the aspect ratio or the axial compressive stress increased. Failure of walls was associated with crushing of masonry. Analytical out-of-plane strength of walls was determined using the yielding line, failure line, modified yielding line, compressive strut and bidirectional strut methods. It was concluded that the experimental out-of-plane strength of walls was best predicted with the bidirectional strut method.

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An Experimental Study of Confined Masonry Walls with Varying Aspect Ratios

Earthquake Spectra ◽

10.1193/090712eqs284m ◽

2015 ◽

Vol 31 (2) ◽

pp. 945-968 ◽

Cited By ~ 21

Author(s):

J. J. Perez Gavilan ◽

L. E. Flores ◽

S. M. Alcocer

Keyword(s):

Aspect Ratio ◽

Good Accuracy ◽

Axial Stress ◽

Masonry Walls ◽

Inelastic Behavior ◽

Ductility Demand ◽

Confined Masonry ◽

Aspect Ratios ◽

Wide Range ◽

Good Agreement

Results from an experimental series of seven full-scale confined masonry walls with height-to-length aspect ratios ( H/L) from 0.3 up to 2.2 are summarized. Results show that neither the level of axial stress nor the aspect ratio had a significant effect on lateral stiffness. Inelastic behavior of the walls, characterized by normalized stiffness degradation with ductility demand, can be estimated with good accuracy with a bilinear function for a ductility demand up to 4.5. A substantial increase in normalized shear strength was observed for walls with decreasing aspect ratio. A correction factor to the nominal cracking strength was deduced based on differences of the flexural deformations for squat and square walls. The factor was then compared to the experimental normalized strength with good agreement. A new expression for inclined cracking shear that can be used for a wide range of wall aspect ratios is proposed.

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Experimental study on seismic performance of strengthening masonry wall using hybrid fiber-reinforced reactive powder concrete

Earthquake Spectra ◽

10.1177/8755293020988012 ◽

2021 ◽

pp. 875529302098801

Author(s):

Xin Wang ◽

Qun Xie ◽

Zhenli Wu ◽

Fanyang Bu ◽

Fei Wang

Keyword(s):

Experimental Study ◽

Seismic Performance ◽

Structural Integrity ◽

Masonry Wall ◽

Reactive Powder Concrete ◽

Masonry Walls ◽

Fiber Reinforced ◽

Hybrid Fiber ◽

Confined Masonry ◽

Reactive Powder

An experimental study was conducted to investigate the seismic performance of masonry walls strengthened using hybrid fiber-reinforced reactive powder concrete (HyFRRPC) as a coating. The proposed reinforcement technique was employed to improve the overall strength and structural integrity of the confined masonry wall. In order to guarantee the composite action between the masonry substrate and the coating material, material tests were conducted to achieve an optimal mixture for the HyFRRPC. Then, six full-scaled confined masonry specimens strengthened by HyFRRPCs with varied strengthening configurations were tested under in-plane quasi-static horizontal loading. The test and analysis results indicated that the proposed HyFRRPC-strengthening technique can effectively improve the lateral carrying capacity, displacement ductility, and energy dissipation capacity of masonry walls, and provide an optimal reinforcement. Finally, a simplified analytical model was also proposed for practical application.

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Use of the AE Effect to Determine the Stresses State in AAC Masonry Walls under Compression

Materials ◽

10.3390/ma14133459 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3459

Author(s):

Radosław Jasiński ◽

Krzysztof Stebel ◽

Paweł Kielan

Keyword(s):

Ultrasonic Waves ◽

Image Correlation ◽

Masonry Walls ◽

Acceptable Error ◽

Compressive Stresses ◽

Deformation State ◽

Hydrostatic Stresses ◽

Stress States ◽

The Impact ◽

Masonry Units

Safety and reliability of constructions operated are predicted using the known mechanical properties of materials and geometry of cross-sections, and also the known internal forces. The extensometry technique (electro-resistant tensometers, wire gauges, sensor systems) is a common method applied under laboratory conditions to determine the deformation state of a material. The construction sector rarely uses ultrasonic extensometry with the acoustoelastic (AE) method which is based on the relation between the direction of ultrasonic waves and the direction of normal stresses. It is generally used to identify stress states of machine or vehicles parts, mainly made of steel, characterized by high homogeneity and a lack of inherent internal defects. The AE effect was detected in autoclaved aerated concrete (AAC), which is usually used in masonry units. The acoustoelastic effect was used in the tests described to identify the complex stress state in masonry walls (masonry units) made of AAC. At first, the relationships were determined for mean hydrostatic stresses P and mean compressive stresses σ3 with relation to velocities of the longitudinal ultrasonic wave cp. These stresses were used to determine stresses σ3. The discrete approach was used which consists in analyzing single masonry units. Changes in velocity of longitudinal waves were identified at a test stand to control the stress states of an element tested by the digital image correlation (DIC) technique. The analyses involved density and the impact of moisture content of AAC. Then, the method was verified on nine walls subjected to axial compression and the model was validated with the FEM micromodel. It was demonstrated that mean compressive stresses σ3 and hydrostatic stresses, which were determined for the masonry using the method considered, could be determined even up to ca. 75% of failure stresses at the acceptable error level of 15%. Stresses σ1 parallel to bed joints were calculated using the known mean hydrostatic stresses and mean compressive stresses σ3.

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In-plane response of unreinforced masonry walls confined by reinforced concrete tie-columns and tie-beams

Advances in Structural Engineering ◽

10.1177/1369433216689569 ◽

2017 ◽

Vol 20 (11) ◽

pp. 1632-1643 ◽

Cited By ~ 4

Author(s):

Masoud Amouzadeh Tabrizi ◽

Masoud Soltani

Keyword(s):

Numerical Study ◽

Nonlinear Behavior ◽

Numerical Approach ◽

Masonry Wall ◽

Masonry Walls ◽

Lateral Loads ◽

Confined Masonry ◽

Smeared Crack ◽

Modeling Strategy ◽

Reversed Cyclic

This article focuses on the experimental and analytical investigations of masonry walls surrounded by tie-elements under in-plane loads. The experimental results of an unconfined and a confined masonry wall, tested under reversed cyclic lateral loads, are presented. For numerical study, a micro-modeling strategy, using smeared-crack-based approach, is adopted. In order to validate the numerical approach, experimental test results and data obtained from the literature are used, and through a systematic parametric study, the influence of adjoining walls and number of tie-columns on the seismic behavior of confined masonry panels is numerically assessed and a simple but rational method for predicting the nonlinear behavior of these structures is proposed.

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