scholarly journals Experimental and Numerical Study of Engineered Cementitious Composite with Strain Recovery under Impact Loading

2019 ◽  
Vol 9 (5) ◽  
pp. 994 ◽  
Author(s):  
Moncef Nehdi ◽  
Mohamed Ali
Keyword(s):  
Shape Memory ◽  
Impact Loading ◽  
Numerical Study ◽  
Absorption Capacity ◽  
Strain Recovery ◽  
Impact Behavior ◽  
Experimental Investigations ◽  
Heating Process ◽  
Cementitious Composite ◽  
Engineered Cementitious Composite

An engineered cementitious composite, endowed with strain recovery and incorporating hybrid shape memory alloy (SMA) and polyvinyl alcohol (PVA) short fibers, was subjected to drop weight impact loading. Numerical simulation of the composite’s impact behavior was performed, and the model predictions agreed well with the experimental findings. Numerical and experimental investigations demonstrated that incorporating SMA fibers in the composite yielded superior impact resistance compared to that of control mono-PVA specimens. Heat treatment stimulated the SMA fibers to apply local prestress on the composite’s matrix owing to the shape memory effect, thus enhancing energy absorption capacity, despite the damage incurred by PVA fibers during the heating process. The superior impact performance of the hybrid composite makes it a strong contender for the construction of protective structures, with a potential to enhance the safety of critical infrastructure assets against impact and blast loading.

scholarly journals Cyclic Behavior of Masonry Shear Walls Retrofitted with Engineered Cementitious Composite and Pseudoelastic Shape Memory Alloy

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 511
Author(s):  
Alireza Tabrizikahou ◽  
Mieczysław Kuczma ◽  
Magdalena Łasecka-Plura ◽  
Ehsan Noroozinejad Noroozinejad Farsangi
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Shear Walls ◽  
Absorption Capacity ◽  
Cyclic Behavior ◽  
Masonry Walls ◽  
Cementitious Composite ◽  
Energy Absorption Capacity ◽  
Engineered Cementitious Composite ◽  
Mesh Density

The behavior of masonry shear walls reinforced with pseudoelastic Ni–Ti shape memory alloy (SMA) strips and engineered cementitious composite (ECC) sheets is the main focus of this paper. The walls were subjected to quasi-static cyclic in-plane loads and evaluated by using Abaqus. Eight cases of strengthening of masonry walls were investigated. Three masonry walls were strengthened with different thicknesses of ECC sheets using epoxy as adhesion, three walls were reinforced with different thicknesses of Ni–Ti strips in a cross form bonded to both the surfaces of the wall, and one was utilized as a reference wall without any reinforcing element. The final concept was a hybrid of strengthening methods in which the Ni–Ti strips were embedded in ECC sheets. The effect of mesh density on analytical outcomes is also discussed. A parameterized analysis was conducted to examine the influence of various variables such as the thickness of the Ni–Ti strips and that of ECC sheets. The results show that using the ECC sheet in combination with pseudoelastic Ni–Ti SMA strips enhances the energy absorption capacity and stiffness of masonry walls, demonstrating its efficacy as a reinforcing method.

Enhancing the out-of-plane behaviour of unreinforced masonry walls under impact loading through the use of partially bonded layers of engineered cementitious composite

2019 ◽  
Vol 11 (2) ◽  
pp. 209-234
Author(s):  
Saeed Pourfalah ◽  
Demetrios M Cotsovos
Keyword(s):  
Impact Loading ◽  
Composite Layer ◽  
Unreinforced Masonry ◽  
Masonry Walls ◽  
Full Potential ◽  
Cementitious Composite ◽  
Premature Failure ◽  
Engineered Cementitious Composite ◽  
Composite Layers ◽  
Out Of Plane

Published experimental work reveals that the out-of-plane behaviour of unreinforced masonry walls under impact loading can be significantly enhanced through the use of engineered cementitious composite layers fully bonded to the surface of the masonry. The disadvantage of this method is associated with the localised cracking exhibited by the engineered cementitious composite layer close to the joints forming between bricks. This cracking is associated with the bond developing between the masonry and the engineered cementitious composite layer and does not allow the latter layer to achieve its full potential, thus resulting in its premature failure. In an attempt to address this problem, a series of drop-weight tests were carried on masonry prismatic specimens strengthened with a layer of engineered cementitious composite partially bonded to the surface of the masonry acting in tension. The latter prismatic specimens consist of a stack of bricks connected with mortar joints. The specimens are considered to provide a simplistic representation of a vertical strip of a masonry wall subjected to out-of-plane actions associated with impact or blast loading. Analysis of the test data reveals that under impact loading, the specimens retrofitted with partially bonded engineered cementitious composite layers can exhibit a more ductile performance compared to that exhibited by the same specimens when strengthened with fully bonded layers of engineered cementitious composite. This is attributed to the fact that along its unbonded length, the engineered cementitious composite layer is subjected to purely uniaxial tension (free from any interaction with the surface of the masonry), allowing for the development of multiple uniformly distributed fine cracks.

Evaluation of reinforced concrete and reinforced engineered cementitious composite (ECC) members and structures using small-scale testing

2015 ◽  
Vol 42 (3) ◽  
pp. 164-177 ◽  
Author(s):  
Bora Gencturk ◽  
Farshid Hosseini
Keyword(s):  
Reinforced Concrete ◽  
Energy Absorption ◽  
High Energy ◽  
Absorption Capacity ◽  
System Level ◽  
Experimental Program ◽  
Small Scale ◽  
Cementitious Composite ◽  
Energy Absorption Capacity ◽  
Engineered Cementitious Composite

The behavior of reinforced concrete (RC) and reinforced engineered cementitious composites (ECC) was comparatively investigated at the component and system levels through a small-scale (1/8 scale factor) experimental program. The logistical and financial advantages of small-scale testing were utilized to investigate a range of parameters, including the effect of reinforcement ratio and material properties, on the response of reinforced concrete and reinforced ECC structures. The procedures pertaining to material preparation, specimen construction, and input motion development that were critical for enhancing the similarity between the scales are provided. Engineered cementitious composite mixtures with different cost and sustainability indices were evaluated. Under cyclic loading, the stiffness, strength, ductility, and energy absorption capacity of columns made of different ECC mixtures were found to be 110, 65, 45, and 100% higher, respectively, than those of the RC columns. The system level investigation through hybrid simulation showed that the ECC structures sustain less deformation under earthquake excitation due to high energy absorption capacity of the material. The differences in cost, sustainability, and structural performance of different ECC mixtures suggest that a careful selection of materials is required for optimal performance.

scholarly journals Axial Strength Of Lightweight Self-Consolidating Concrete Columns With Engineered Cementitious Composite

2021 ◽  
Author(s):  
Sandeep Parajuli
Keyword(s):  
Axial Load ◽  
Failure Modes ◽  
Load Capacity ◽  
Absorption Capacity ◽  
Normal Weight ◽  
Cementitious Composite ◽  
Concrete Core ◽  
Self Consolidating Concrete ◽  
Engineered Cementitious Composite ◽  
Axial Strength

Axial load behavior of confined columns with engineered cementitious composite (ECC) wrapping was investigated through experimental, analytical and finite element (FE) investigations. The variables in the study were: geometry (cylindrical and rectangular), presence or absence of longitudinal and tie reinforcement, ECC wrap thickness, types of concrete core (lightweight and normal weight self-consolidating concrete) and type of loading (applied through both core and wrap or core only). The effect of these variables on axial load-deformation response, strain characteristics, failure modes, ductility, energy absorption capacity and axial strength were evaluated. The confined concrete strengths predicted from existing analytical and developed FE models were found to be in good agreement with those of experiments. The axial load capacity and ductility were increased for columns with highest ECC wrap thickness (50 mm) while thinner wrap increased stiffness instead of ductility. Canadian code conservatively predicted axial strength of columns having increased thickness of ECC wrap.

scholarly journals Axial Strength Of Lightweight Self-Consolidating Concrete Columns With Engineered Cementitious Composite

2021 ◽  
Author(s):  
Sandeep Parajuli
Keyword(s):  
Axial Load ◽  
Failure Modes ◽  
Load Capacity ◽  
Absorption Capacity ◽  
Normal Weight ◽  
Cementitious Composite ◽  
Concrete Core ◽  
Self Consolidating Concrete ◽  
Engineered Cementitious Composite ◽  
Axial Strength

Axial load behavior of confined columns with engineered cementitious composite (ECC) wrapping was investigated through experimental, analytical and finite element (FE) investigations. The variables in the study were: geometry (cylindrical and rectangular), presence or absence of longitudinal and tie reinforcement, ECC wrap thickness, types of concrete core (lightweight and normal weight self-consolidating concrete) and type of loading (applied through both core and wrap or core only). The effect of these variables on axial load-deformation response, strain characteristics, failure modes, ductility, energy absorption capacity and axial strength were evaluated. The confined concrete strengths predicted from existing analytical and developed FE models were found to be in good agreement with those of experiments. The axial load capacity and ductility were increased for columns with highest ECC wrap thickness (50 mm) while thinner wrap increased stiffness instead of ductility. Canadian code conservatively predicted axial strength of columns having increased thickness of ECC wrap.

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