Fig 4 - uploaded by Sid Pourfalah
Content may be subject to copyright.
Tensile testing of ECC dog-bone shaped samples a) schematic diagram; b) sample during uniaxial tensile testing.
Source publication
A novel technique for enhancing the out-of-plane behaviour of masonry infill walls is proposed herein. The technique involves the use of a thin layer of engineered cementitious composite (ECC) which is fully or partially bonded onto the face of masonry walls. To investigate the feasibility of this technique, the present research focuses on studying...
Contexts in source publication
Context 1
... tensile testing of ECC dog-bone specimens: Ten dog-bone shaped specimens with 211 dimensions in accordance to JSCE (2008) [34] (see Figure 4a) were prepared to study the 212 ECC material behaviour under uniaxial tensile loading. The ECC binder comprised of CEM I 213 52.5N Portland cement in accordance with BS EN197-1 [29] and fine fly-ash (Superpozz 214 SV80, Scotash). ...
Similar publications
When concrete members are exposed to fire, the compressive performance of the material will be severely reduced. To ensure the safety of the members, it is necessary to analyze the impact of high temperature on the performance of concrete members and strengthen them appropriately. ECC with remarkable tensile strain-hardening characteristics and exc...
Extensive research has been conducted on the uniaxial tensile and compressive behavior of engineered cementitious composites (ECC). Despite the high tensile ductility and high toughness of ECC, transverse steel reinforcement is still necessary to confine ECC for high performance structural members made of ECC. However, very limited research has bee...
The purpose of this study is to propose and demonstrate the effectiveness of engineered cementitious composite (ECC) for strengthening block masonry. Two cases have been studied: ECC only on the tension face and ECC on both tension and compression faces. Out-of-plane response of tension reinforced beam, and both tension and compression reinforced b...
This research will help to improve our understanding of the fracture properties of ECC at low temperatures (long-term low temperatures, freeze–thaw) and evaluate the safety properties of ECC under low-temperature conditions. Three levels of saturation (saturated, semi-saturated, and dry), four target temperatures (20, 0, −20, and −60 °C), and the e...
Citations
... 본 연구에서는 조적조 벽체의 내진 보강 재료로 HPFRCC (High-Performance Fiber-Reinforced Cementitious Composite) 에 주목하였다 (Chun et al., 2022;Lee, 2022;Lee and Yoo, 2023). 조적조의 내진 보강을 위해 시멘트 복합체를 단독으 로 사용한 것은 ECC (Engineered Cementitious Composites), UHDC (Ultra-High Ductile Concrete), UHPC (Ultra-High-Performance Concrete) 등으로 불리는 높은 인장 강도와 연성 을 갖는 시멘트 복합체가 개발되면서 시작되었다 (Maalej et al., 2010;Pourfalah et al., 2018 (1)과 같이 정의하였다. ...
Frequent earthquake occurrences in various regions of Korea have highlighted the urgent need that exists for the seismic retrofitting of unreinforced masonry buildings, which are particularly vulnerable to lateral forces. In this study, the out-of-plane seismic performance of masonry walls reinforced with high-performance fiber-reinforced cementitious composites (HPFRCCs) was evaluated using finite element analysis. ABAQUS was used to establish the analysis model, and the reliability of the model was validated by comparing the model results with shaking table test results. A parametric study of the reinforced masonry walls was thereafter conducted using the parameters of the reinforced sides of the walls (unilateral and bilateral) and thicknesses (10 and 20 mm). The analysis of the acceleration and displacement of the masonry walls revealed the beneficial effects of HPFRCCs on the out-of-plane seismic performance of the walls. The seismic performance of the walls was significantly enhanced when the HPFRCCs were applied to both sides of the walls.
... ECC can be used as the potential retrofitting material due to its ease in manufacturing, high tensile strain capacity, high ductility, and strain hardening properties. Past studies (Dehghani et al. 2015;Kyriakides and Billington 2014;Pourfalah et al. 2018) showed that the flexural performance of the masonry beam could be significantly improved by the application of ECC layer in terms of the flexural strength and ductility. During the event of an earthquake, the masonry structure may experience excessive lateral loading. ...
... The test results of the shear and normal strength of brick-mortar and brick-ECC interfaces are presented in Fig. 8 and A similar type of study was performed by Pourfalah et al. (2018) where the average value of the shear stress and shear stiffness of the interfaces were obtained from the shear stress versus displacement plots for zero normal stress condition. In the present study, shear tests were not performed under normal stresses, and the shear stress and shear stiffness values corresponding to zero normal conditions were opted for the numerical modeling. ...
The effect of the ductile engineered cementitious composites (ECC) on the unreinforced masonry (URM) prisms and beams was investigated through the appropriate experiments. The objective of the study was to propose a cost-effective strengthening scheme using a low-cost ECC which was prepared using polyester fibers that possessed moderate tensile strength and ductility. The performance of masonry prisms and beams was investigated with different strengthening schemes. Test results showed that with the application of the ECC layer, the strength of masonry could be significantly improved under flexural loads, and the brittle collapse was mitigated. The ECC retrofitted masonry prism possessed a maximum increase in strength and stiffness of 74% and 50%, respectively. A numerical model was developed based on the basic mechanical properties and the interfacial properties of the individual elements (ECC, brick, and mortar). The numerical model was able to accurately predict the peak strengths and the failure modes of the masonry prisms and the beams.
... Some of the first studies on this issue used the textile-reinforced mortar technique [40,41]. Some other works were carried out recently using this technique again [42][43][44] but also others such as Fibre-Reinforced Polymer [45] and Engineered Cementitious Composites [46]. ...
The masonry infill walls are often used in the envelopes of reinforced concrete buildings for different purposes, but a large part of them was built before the enforcement of modern seismic and/or energy codes. Due to that, the envelope of the reinforced concrete buildings is responsible for the energy consumption needed for indoor heating and cooling. At the same time, recent earthquakes proved that the infill walls located at the envelope are quite vulnerable under OOP seismic loadings resulting in extensive damage or collapse. The existing standards only provide slight provisions for designing new infill walls and do not combine their energy and seismic performance. Based on that, this research work aims to present a novel holistic performance assessment approach for masonry infill walls. This novel approach aims to classify each wall according to its seismic plus energy performance, allowing to identify which type of retrofitting is needed. A global overview of the international standards concerning the seismic design and assessment of masonry infill walls is performed. Also, the maximum and recommended U-values for external walls indicated by the national code of each European Union country are compared. After that, the new performance assessment methodology is presented and discussed. Finally, a pilot application is performed by carrying out the performance assessment of the infill walls of three buildings (with different numbers of storeys) located in different seismic-climate zones in Portugal. Several types of walls are studied according to their retrofitting type, i.e. non-retrofitted or with independent energy or seismic retrofitting or with combined seismic plus energy retrofitting. It was found that this performance assessment methodology provides important information to support future wall retrofitting. Combined seismic plus energy retrofitting is often needed in the different seismic-climate zones of the Portuguese territory.
... Over the past decades, multiple configurations, such as setting ring beams and tie-columns [12,13], applying varying magnitudes of posttensioning [14,15], injecting anchors [16,17], troweling ferrocement [18,19], welding wire mesh [20,21], affixing fiber reinforced polymer (FRP) strip [22][23][24][25], plastering with textile-reinforced mortar (TRM) layer [26][27][28][29], and daubing engineered cementitious composite (ECC) [30,31], have been designed to improve the flexural performance and deformation capacity of masonry walls. These measures can enhance the bearing capacity, deformation, and absorbed energy of the elements to varying degrees. ...
... ECC can be used as the potential retrofitting material due to its ease in manufacturing, high tensile strain capacity, high ductility, and strain hardening properties. Past studies (Kyriakides and Billington 2014, Dehghani et al. 2015, and Pourfalah et al. 2018 showed that the flexural performance of the masonry beam could be significantly improved by the application of ECC layer in terms of the flexural strength and ductility. The present study investigates the out-of-plane flexural strength of the masonry wallets (with and without the ECC layer) for the failure planes parallel and perpendicular to the bed joints. ...
The unreinforced masonry and infill masonry walls may experience in-plane/ out-of-plane failure modes or a combination of both during seismic events. The unreinforced masonry elements are primarily designed to withstand the in-plane compression load without considering the lateral forces generated in the seismic events. In occurrences of seismic events, these elements may experience additional horizontal forces along the in-plane and out-of-plane directions that may lead to the collapse of the masonry elements in the out-of-plane directions in a brittle manner due to loss of flexural strength. The strain hardening and the multiple cracking properties make the ECC an ideal material for retrofitting the structures due to ductile post-elastic response and better energy dissipation. A low-cost ECC was developed using locally available polyester fiber and easily available materials such as Portland Pozzolana cement (PPC), Fly Ash, and river sand. An experimental program was conducted to evaluate the out-of-plane flexural strength of masonry wallets strengthened using ECC. The performance of wallets was investigated in two modes of application of the ECC layer: single-layer application and double-layer application. Test results showed that with the application of the ECC layer, the strength and ductility of masonry could be significantly improved under flexural loads, and the brittle collapse was mitigated. It was found that both single-layer and double-layer applications of ECC showed comparable results in out-of-plane flexural load. However, the double-layer application of the ECC layer was helpful in mitigating the brittle failure, and ductile behavior was observed. The flexural strength of the masonry wallet was increased up to 10 times as compared to the control specimen after the application of the ECC layer. The ECC used in the present study demonstrated an ultimate strength of 2.18 MPa and tensile ductility of 1.65%.
... Engineered Cementitious Composites (ECC) onto the surface of walls has significantly enhanced the out of plane behavior in respect of deformability and strength as compared to the un-strengthened masonry walls. The application of ECC as partially bonding technique onto the brick masonry surface has enabled the structures to achieve maximum deformability before the structure fails [12]. ...
The objective of this study is to examine the behavior and determine the potential implications
of Engineered Cementitious Composites (ECC) to strengthen the concrete block masonry by using a unique
method of partially bonding the tension face as tension strengthened beam under the out of plane loadings.
The specimens under investigation were comprised of two categories i.e. un-strengthened concrete block
masonry beams and tension strengthen beams with different thicknesses of ECC layers. All the specimens
were experimented under the four point loadings to evaluate the flexural performance of fabricated beams.
The current study reveals that the partially bonded ECC strengthening of concrete block masonry beams
has significantly improved the strength and deformability
... More localized cracks were observed in drop weight tests. Pourfalah [26] found that a high loading rate implies a high moment capacity and a small deformation. ...
Fiber-reinforced polymers (FRPs), textile-reinforced mortars (TRMs), and engineered cementitious composites (ECCs) have been extensively employed to address the insufficient load-carrying capacity and low deformation capability of unreinforced masonry buildings. In this study, eight groups of unreinforced masonry walls were built to test the efficiencies of various reinforcing methods under out-of-plane four-point loading. A high-strength mortar reinforcement were employed as benchmarks. Four types of ECCs—low-cost, high-strength, lightweight insulation, and high-toughness ECCs—were compared with carbon FRP (CFRP) sheet and TRM systems. The failure modes, midspan load–displacement actions, energy absorption capabilities, initial bending stiffness values, and ductility of the different reinforcement systems were obtained and analyzed. The results revealed that the TRM-reinforced specimens experienced the maximum midspan deformation. The best ductility and maximum bearing capacity were obtained respectively after reinforcements with high-strength and high-toughness ECCs. However, the exploitation of the CFRP sheet was limited owing to excessive reinforcement. Finally, the moment capacity was evaluated using a flexural model. For the specimens that failed in the shear mode, a shear model based on the equilibrium condition was established to predict their load-carrying capacities.
... However, the poor toughness of the matrix, serviceability, and utilization rate, which is the ratio of the actual strength of the textile to its theoretical value, still need to be improved [13]. The use of cementitious composites alone for seismic reinforcement of masonry began with the development of cementitious composites with high tensile strength and ductility, called engineered cementitious composites (ECC), ultra-high ductile concrete (UHDC), ultra-high-performance concrete (UHPC), etc. [19][20][21][22][23][24][25][26]. Soleimani-Dashtaki [27] developed an eco-friendly ductile cementitious composite (EDCC) with excellent ductility and toughness for retrofitting unreinforced brick masonry walls. ...
Masonry structures are very vulnerable to lateral forces such as earthquakes. In particular, for existing masonry buildings that have not been designed for earthquake resistance, appropriate seismic resistance retrofit is required. In this study, ultra-rapid-hardening fiber-reinforced mortar (URH-FRM), which has a high ductility, with an ultimate tensile strain of about 0.07, and is an economical and easy-to-construct seismic reinforcing material, was developed. Compressive strength and initial shear strength tests were performed on masonry prisms reinforced with the URH-FRM. As an experimental variable, the reinforcement thickness of the URH-FRM was varied from 10 to 30 mm and the structural performance was compared with specimens reinforced with general mortar and specimens without reinforcement. As a result, the beneficial effect of URH-FRM on the in-plane initial shear strength of horizontal bed joints in masonry prisms was confirmed. In addition, the thicker the URH-FRM reinforcement, the clearer the improvement in ductility through strain hardening.
... The masonry walls must be built in a way that they can easily bear the external loads to ensure public safety, structural integrity, and resilience [4], [5]. The out-of-plane efficiency can be improved when ECC layers are added to the masonry walls [6]. A fully coated layer of ECC applied to the face of block masonry is predicted to improve out-of-plane efficiency, including load-bearing capabilities and ductility [7]. ...
The purpose of this study is to propose and demonstrate the effectiveness of engineered cementitious composite (ECC) for strengthening block masonry. Two cases have been studied: ECC only on the tension face and ECC on both tension and compression faces. Out-of-plane response of tension reinforced beam, and both tension and compression reinforced beam has been experimentally investigated under four-point loading systems. The findings of this study show that both the strength and ductility of masonry beams enhance using ECC, which advocates the use of ECC as a block masonry reinforcing material.
... Reinforcing the URM walls has been previously performed by using FRP sheets on the wall surface, increasing the out-of-plane load capacity by more than 600% and sliding shear failure [14,15]. Utilizing bendable concrete such as engineered cementitious composites (ECC) to strengthen masonry walls has increased ductility by more than 20 times [16][17][18][19][20]. ...
Lateral loads cause extensive damage to buildings due to the weakness of bearing out-of-plane un-reinforced masonry (URM) walls. Strengthening URM walls is consequently favored by researchers aiming at achieving building and respective occupant safety. The strengthening of masonry structures with textile reinforced mortar (TRM) or steel-reinforced mortar (SRM) has become prevalent in the last two decades. This study presents an innovative method of strengthening masonry walls using mortar reinforced with high tensile strength steel (HTSS) parallel wires. For the first time, an unprecedented investigation as to the effects of the grooving method improving the load-carrying capacity and failure mechanism of masonry walls under out-of-plane loading was performed. In addition, the parallel wires steel-reinforce mortar (PW-SRM) was compared with the textile-reinforced mortar (TRM) reinforcement method. Nine walls with dimensions of 1400 × 440 × 100 mm each were reinforced through different techniques and tested under four-point out-of-plane bending. The implications of the number of glass textiles with open mesh layers, one-sided and two-sided reinforcement, engineered cementitious composites (ECC), grooves on the masonry substrate, and, the volume of HTSS wires in increasing out-of-plane loading were compared and discussed. The findings demonstrated that the best performance is related to the specimens reinforced by the PW-SRM method. Similarly, the amount of out-of-plane load-bearing capacity and energy absorption increased more than 24 and 5300 times compared to the control specimen, respectively. It was further discovered that the grooving method transferred the tensile stress created in the TRM composite to the depth of the masonry substrate, which enhanced the failure mechanism from debonding to textile rupture and increased the strength by 88% compared to the corresponding specimen without grooves.
