Wall Specimens Research Articles

Experimental and numerical study on the seismic behavior of groove grouting precast concrete shear walls with different joint types

A groove grouting precast concrete shear wall (GGPCSW) subjected to seismic performance tests was explored in this research. Four full-scale specimens were designed for use in quasi-static experiments. These specimens included three GGPCSWs with different joint types (i.e., a horizontal joint, a vertical joint, and a combination of horizontal and vertical joints) and one reference cast-in-place reinforced concrete shear wall (CIPRCSW). The failure modes, failure process, hysteresis curves, bearing capacity, stiffness degradation, and ductility of the GGPCSWs were clarified. The experimental results revealed that all shear wall specimens failed in the flexural-shear failure mode. The crack distribution, load capacity, energy consumption, and stiffness degradation of the GGPCSW with a horizontal joint were found to be basically the same as those of the CIPRCSW before the displacement angle reached 1/100. The positive load capacity of the GGPCSW with a vertical joint was 22.5% greater than that of the CIPRCSW under the same conditions. It is noteworthy that the peak load of the GGPCSW with a combination of horizontal and vertical joints was basically the same as that of the GGPCSW with a vertical joint, while the ultimate displacement was 14% less than that of the GGPCSW with a horizontal joint. Furthermore, the GGPCSWs demonstrated a comparable level of ductility to the CIPRCSW, meeting the necessary deformability criteria. Finally, a series of numerical analyses were completed to investigate the skeleton curves, the distribution of the concrete damage, and the stress distribution of the steel bars. The findings were basically consistent with the test results, and further parametric investigations of GGPCSWs were performed.

Examining Mechanical Properties of Strengthened Aerated Concrete Masonry Walls

Masonry structures primarily rely on their walls as the principal load-bearing components. The walls are brittle materials such as natural stone, sandstone and brick. The walls of masonry structures have lack of the deformation capacity and to resist the tensile stresses caused by earthquake forces, settlement of foundation, and so on. To avoid loss in bearing capacity or to have more strength against lateral loads, during the production or after some precautions can be taken. The aim of this study is to investigate the behavior of strengthened aerated concrete walls by clamps. Six samples were tested under diagonal compression. All tested samples were knitted with mortar advised by the aerated concrete producer. The left five samples were knitted using different orientation of clamps and anchors made out of Ø12 deformed bars and welded plates. According to the experimental test results, it was observed that the interconnection of aerated concrete blocks with different combinations had increased stiffness, energy consumption capacity, and load bearing capacity of the walls. In addition to the brittle behavior of the reference specimen, the strengthened wall specimens have exhibited more ductile behavior.

Seismic behavior and modeling of T‐shaped reinforced concrete walls under high axial force ratios

AbstractThis paper presents large‐scale quasi‐static tests conducted to investigate the seismic behavior of slender T‐shaped walls under a high axial compression force ratio of approximately 0.19. Four specimens were designed per various codes and design methods for comparison. All specimens failed in a flexural mode, characterized by the crushing of concrete and buckling or fracture of boundary longitudinal rebars at the web toe. The specimens designed per the US code ACI 318‐19 provisions and designed using displacement‐based method exhibited satisfactory deformation capacity with an ultimate drift exceeding 2.0%, which validates the effectiveness of the provisions and displacement‐based method for T‐shaped walls under high axial force ratios. However, the specimen designed per the Chinese code GB 50011‐2010 experienced a sudden drop in strength after 1.0% drift in flange‐in‐tension loading, indicating insufficient design of the special boundary element at the web toe and the necessity of improvement of the current Chinese code provisions. The flexural strength of the T‐shaped wall specimens can be accurately estimated using cross‐sectional analysis. Analysis of the test data indicated that the effective stiffness of the T‐shaped RC walls with an axial force ratio of no greater than 0.1 was significantly lower than 0.35EcIg, while that of the T‐shaped walls with an axial force ratio of 0.19 reached 0.5–0.7EcIg. Existing equations did not provide accurate estimate of the effective stiffness of T‐shaped walls. The lateral drift limit formulation developed by Segura and Wallace could reasonably estimate the lateral drift capacities for the T‐shaped RC wall specimens under high axial force ratios. Finally, three conceptually different models, namely the MVLEM‐3D, SFI‐MVLEM‐3D, and multi‐layer shear element models were adopted for the simulation of T‐shaped RC walls. All three models reasonably predicted the flexural strength capacity (mostly less than 15% error) and the effective stiffness (13%–43% error) of the T‐shaped walls.

Seismic performance of high-strength steel plate-concrete composite shear walls

The application of high-strength steel plate-concrete composite shear walls in super high-rise frame-core tube structure can significantly increase the bearing capacity, reduce the dimensions of the core tube and the frame part, and harmonize the stiffness ratio of frame and core tube, therefore improve the economic efficiency. In order to study the seismic performance of the high-strength steel plate-concrete composite shear walls, pseudo-static tests on three composite shear wall specimens with an aspect ratio of 1.43 were conducted, the failure mechanism, strength, ductility and energy dissipation capacity of specimens with Q355B, Q460B, Q550B steel were studied. Experimental results showed that the crushing of concrete and the failure of vertical reinforcement at the corner leaded to the flexural failure of specimens; hysteresis curves of specimens showed good energy dissipating capacities without pinching phenomena; with the increase of the steel strength, the yield strength, yield displacement, peak strength and ultimate displacement of specimens increased, while ductility decreased. Finite element analysis was conducted using OpenSees, the modeling method had been proven accurately simulate the performance of the specimens, and was subsequently used for parametric study to investigate the impact of axial compression ratio, thickness of the embedded steel plate, and aspect ratio (height to width) on the performance of high-strength steel plate-concrete composite shear walls.

Seismic performance of innovative prefabricated reinforced recycled concrete shear walls

In this study, the seismic performance of innovative prefabricated recycled concrete shear walls has been investigated. Unlike the conventional grouting sleeve connections, the "button-head bars" grouting connections to connect the walls have been proposed. Four shear wall specimens with different construction types (two semi-prefabricated, one fully-prefabricated, and one cast-in-place) were tested under low-cyclic loading. The fully-prefabricated wall was connected to the foundation only using the proposed button-head bars; while for the semi-prefabricated walls, the two cast-in-place concealed columns were arranged at both edges of the wall. The failure modes, hysteretic behavior, skeleton curves, strength, ductility, stiffness and degradation process, energy dissipation, and strain characteristics were investigated. The influence of axial force ratio and construction type on the seismic performance of the shear walls was analyzed. The results showed that the seismic performance of semi-prefabricated shear walls and cast-in-place shear walls was similar. The shear slip for the cast-in-place, semi-prefabricated, and fully-prefabricated shear walls was 0.3 mm, 0.32 mm, and 0.78 mm, respectively. The cast-in-place concealed columns could effectively limit horizontal shear slip. An increase in the axial force ratio significantly enhanced the strength and energy dissipation capacity of semi-prefabricated specimens. The ultimate strength according to different design codes was calculated, with the Chinese GB-50010 design code providing the most accurate prediction of the strength of prefabricated shear walls.

Seismic performance of RC frame-shear wall dual structural systems

The two structural systems named “functional integration structural systems” and “functional separation structural systems” were proposed based on the design concept of energy dissipation. To study the seismic performance of reinforced concrete (RC) frame-shear wall dual structural systems in which shear walls are used for “functional integration” and “functional separation”, quasi-static tests of two single-story and two-span RC frame-shear wall specimens with a scale of 1:3 were carried out, and numerical simulation analysis of two five-story frame-shear wall dual structures based on the conditional mean spectrum-incremental dynamic analysis (CMS-IDA) method was carried out. The shear walls bearing lateral load and a small part of the vertical load are named functional separation structure. When the shear walls bearing both lateral load and vertical load are named as functional integration structure, the seismic performance was investigated in terms of crack initiation and damage, hysteresis performance, stiffness degradation, energy dissipation capacity, ductility of the specimens, and seismic collapse resistance of the whole structure. The studies showed that when the load-bearing function and lateral resistance function of the shear walls were separated, the structure had better ductility, energy dissipation capacity, damage development process, and seismic collapse resistance.

Assessment of plasma soluble Tie-2 level to distinguish moyamoya disease from atherosclerotic cerebrovascular disease and predict postoperative neovascularization.

Moyamoya disease (MMD) is a chronic steno-occlusive cerebrovascular disease and features the formation of hazy collateral vessels at the base of the brain. Angiopoietin (Ang)-1 and -2, their receptor Tie-2, and vascular endothelial growth factor (VEGF) that regulate angiogenesis might be important in MMD pathophysiology and postoperative collateral formation. The goal of this study was to determine whether levels of these angiogenic factors could predict collateralization in patients with MMD. A total of 196 patients with MMD and 57 with atherosclerotic cerebrovascular disease serving as controls were enrolled. Ang-1, Ang-2, Tie-2, and VEGF mRNA levels were analyzed in middle cerebral artery (MCA) arterial wall specimens by using real-time quantitative polymerase chain reaction. MCA and peripheral plasma concentrations of Ang-1, Ang-2, soluble Tie-2 (sTie-2), and VEGF were examined by enzyme-linked immunosorbent assay. Cerebral arteriography was performed 6 months after bypass surgery to assess the postoperative collateralization. In MCA specimens, patients with MMD exhibited higher expression levels of Ang-1 and Ang-2 but lowered VEGF expression. The patients with MMD had significantly higher concentrations of Ang-1 and Ang-2 but lower levels of VEGF in MCA plasma. Peripheral plasma concentrations of these growth factors were not changed. MCA and peripheral plasma sTie-2 levels were both reduced in patients with MMD. The 6-month follow-up showed that patients with good collateral formation had lower sTie-2 levels in both MCA and peripheral plasma. Furthermore, the Suzuki stage and peripheral plasma sTie-2 level were significantly correlated with good postoperative collateral formation on multivariate analysis. Ang-1, Ang-2, Tie-2, and VEGF are involved in MMD pathogenesis. The peripheral plasma level of sTie-2 can differentiate MMD from atherosclerotic cerebrovascular disease and serve as a novel biomarker to predict postoperative collateral formation.

Mechanical property test and numerical analysis of a novel precast shear wall

A novel fully assembled composite wall was developed to achieve a mechanical and convenient assembly connection with horizontal and vertical joints connected by bolts. Pseudo-static tests were conducted on four 1/2 scale assembled composite wall specimens, including three fully assembled composite walls and one specimen with vertical joints cast–in–situ. The horizontal joints of all specimens are connected by bolts with the same specification. Subsequently, a finite element model was constructed, and parametric studies were conducted. The test results indicate that the failure of all specimens was caused by the failure of the wallboard, and the connectors have no obvious plastic deformation. The bearing capacity and energy dissipation of the fully assembled composite walls are slightly less than those of the vertical joints cast–in–situ (91.8% and 90.3% respectively). However, their deformation capacity was similar. Overall, the proposed connection method has the potential to replace cast-in-place connected walls in low-rise buildings.

Study on Vertical Dowel Connections in Precast Walls

Precast concrete wall connections using dowels are becoming more popular and effective these days due to their ease of installation and cost. In this study, one-third scale models of slender and intermediate precast walls with dowel connections and monolithic concrete walls were tested experimentally and numerically under lateral cyclic loads. The experiments on precast walls and monolithic walls were conducted on a loading frame of capacity 20 T and the cyclic loads were applied until the failure of the wall specimens. The numerical studies on walls were carried out using Abaqus.cae software, and the same cyclic loads were applied. The responses such as ultimate load, displacement, cracking pattern, ductility, and energy dissipation capacity of precast walls were compared. The results obtained from the numerical investigation proved to be effective in simulating the actual behavior of the studied precast and monolithic walls, thereby reducing the burden of doing physical tests on a huge number of precast wall specimens.

Seismic behavior of non-seismically designed shear walls with moderate shear span under high axial loads

This study investigates the seismic behavior of reinforced concrete (RC) non-seismically designed shear walls with moderate shear span-to-length ratios (SLR), while being subjected to high axial loads. Four shear wall specimens were fabricated and tested, including three specimens with an SLR of 1.58 and one with an SLR of 2.0. The applied axial load ratios (ALR) ranged from 0.30 to 0.35. Detailed test results, such as crack patterns, failure modes, hysteresis curves, stiffness degradation, and energy dissipation, are presented and analyzed. The test results show that all specimens, with different shear-to-flexure strength ratios (SFSR), experienced axial failure and were unable to sustain the target axial load at the end of the test. Among these specimens, three with SFSR values ranging from 0.82 to 1.24 failed in axial failure, while the specimen with an SFSR of 0.44 initially experienced shear failure, followed by axial failure after completing half a cycle. This indicates that SFSR has a significant effect on the failure mode of the shear walls under high ALR. Additionally, the test results obtained in this study are compared with the results of a previous study, in which test specimens had identical reinforcement detailing as in this study but were subjected to lower axial loads (ALR = 0.15–0.20), to investigate the effect of ALR on seismic behavior of shear walls in terms of failure mode, hysteretic curves. The observations show that for specimens with relatively higher SFSR (≥ 0.8), a high level of ALR not only affects the failure mode but also diminishes their deformability. In contrast, for the specimen with a low SFSR (0.44), the effect of ALR on deformability is minimal. Finally, a criterion for determining the occurrence of axial failure in shear walls is proposed.

Study on the post-fire axial compressive performance of the lightweight ceramsite foamed concrete sandwich composite shear wall

This study is carried out to develop a new lightweight ceramsite foamed concrete sandwich composite shear wall, which is a new and affordable building system. The shear wall consists of two ordinary concrete wythes and a ceramsite foamed concrete intermediate sandwich layer between the wythes. Experimental investigation on five shear wall specimens is conducted by varying the parameters such as thickness of the ordinary concrete wythes and the insulation layer, reinforcement pattern and constrained component. Besides, by conducting fire test and axial compressive load test, the results are obtained, including the apparent phenomenon after fire, crack pattern and failure modes, load capacity, load-out of plane curve, strain distribution of the composite sandwich shear wall. The results show that sandwich ceramsite foamed concrete has good thermal insulation performance, and the compositeness of wythes and sandwich layer has reached in a certain degree. However, the compositeness of specimen using truss bars is weaken in the late loading stage and truss bars are advised to be used with the horizontal tie bars in practical engineering application. Compared with other specimens, the experiment ultimate strength has been increased by approximately 75 % by arranging the constrained component on the wall. Finite Element (FE) analysis is also conducted by ABAQUS and the results shows good agreement with experiment results, indicating that the FE model can be used to predict the behavior of the sandwich composite shear wall. Based on the existing methods, a modified method to calculate ultimate compressive bearing capacity after fire is proposed, with the maximum calculation error of 19 %, which shows that all methods can be applied to the practical engineering design.

Assessment of critical parameters affecting the behaviour of bearing reinforced concrete walls under fire exposure

PurposeThis research paper aims to investigate reinforced concrete (RC) walls' behaviour under fire and identify the thermal and mechanical factors that affect their performance.Design/methodology/approachA three-dimensional (3D) finite element (FE) model is developed to predict the response of RC walls under fire and is validated through experimental tests on RC wall specimens subjected to fire conditions. The numerical model incorporates temperature-dependent properties of the constituent materials. Moreover, the validated model was used in a parametric study to inspect the effect of the fire scenario, reinforcement concrete cover, reinforcement ratio and configuration, and wall thickness on the thermal and structural behaviour of the walls subjected to fire.FindingsThe developed 3D FE model successfully predicted the response of experimentally tested RC walls under fire conditions. Results showed that the fire resistance of the walls was highly compromised under hydrocarbon fire. In addition, the minimum wall thickness specified by EC2 may not be sufficient to achieve the desired fire resistance under considered fire scenarios.Originality/valueThere is limited research on the performance of RC walls exposed to fire scenarios. The study contributed to the current state-of-the-art research on the behaviour of RC walls of different concrete types exposed to fire loading, and it also identified the factors affecting the fire resistance of RC walls. This guides the consideration and optimisation of design parameters to improve RC walls performance in the event of a fire.

Experimental study on the seismic performance of concrete shear walls partially replaced by MRPC

Shear wall structures are widely used in high-rise buildings, due to their satisfactory integrity and force transmission, thus superior seismic performance. However, due to insufficient material strength, non-standard construction, and the fact that some buildings have reached their design service life, many shear wall structures can no longer resist natural disasters such as earthquakes, nor can they meet the functional requirements. Therefore, it is of practical significance to reinforce shear wall structures and study their seismic performance. This paper uses the partial replacement method to reinforce and renovate concrete shear walls, using modified reactive powder concrete (MRPC) with excellent durability and toughness as the replacement material. The effects of different materials and different replacement positions on the seismic performance of shear walls were studied. A total of 5 shear wall specimens were designed and manufactured, including Specimen SW1 that did not reach the designed concrete strength, Specimen SW2 that met the original design strength, SW3 with the middle part of the wall was replaced by MRPC, and another two specimens that used ordinary concrete (SW4) or MRPC (SW5) to replace the two ends of the wall. Pseudo-static tests were carried out on the specimens and their seismic performance indicators such as bearing capacity, stiffness degradation, displacement ductility, and energy dissipation capacity were analyzed. Finally, finite element simulation analysis was also performed for the specimens. The results show that compared with the original design strength specimen SW2, the specimens SW4 and SW5, which used C45 concrete and MRPC to replace the two ends of the walls, effectively improved the bearing capacity, energy dissipation, and ductility of the shear wall. By comparing the mechanical properties of SW3 and SW5, it can be found that replacing the two ends of the shear wall can obtain better results.

Biomechanical characterization of the passive porcine stomach

The complex mechanics of the gastric wall facilitates the main digestive tasks of the stomach. However, the interplay between the mechanical properties of the stomach, its microstructure, and its vital functions is not yet fully understood. Importantly, the pig animal model is widely used in biomedical research for preliminary or ethically prohibited studies of the human digestion system. Therefore, this study aims to thoroughly characterize the mechanical behavior and microstructure of the porcine stomach. For this purpose, multiple quasi-static mechanical tests were carried out with three different loading modes, i.e., planar biaxial extension, radial compression, and simple shear. Stress-relaxation tests complemented the quasi-static experiments to evaluate the deformation and strain-dependent viscoelastic properties. Each experiment was conducted on specimens of the complete stomach wall and two separate layers, mucosa and muscularis, from each of the three gastric regions, i.e., fundus, body, and antrum. The significant preconditioning effects and the considerable regional and layer-specific differences in the tissue response were analyzed. Furthermore, the mechanical experiments were complemented with histology to examine the influence of the microstructural composition on the macrostructural mechanical response and vice versa. Importantly, the shear tests showed lower stresses in the complete wall compared to the single layers which the loose network of submucosal collagen might explain. Also, the stratum arrangement of the muscularis might explain mechanical anisotropy during tensile tests. This study shows that gastric tissue is characterized by a highly heterogeneous microstructure with regional variations in layer composition reflecting not only functional differences but also diverse mechanical behavior. Statement of SignificanceUnfortunately, only few experimental data on gastric tissue are available for an adequate material parameter and model estimation. The present study therefore combines layer- and region-specific stomach wall mechanics obtained under multiple loading conditions with histological insights into the heterogeneous microstructure. On the one hand, the extensive data sets of this study expand our understanding of the interplay between gastric mechanics, motility and functionality, which could help to identify and treat associated pathologies. On the other hand, such data sets are of high relevance for the constitutive modeling of stomach tissue, and its application in the field of medical engineering, e.g., in the development of surgical staplers and the improvement of bariatric surgical interventions.

Sectional strength design of a double-skin truss-reinforced composite shear wall

The double-skin truss-reinforced composite shear wall is an innovative element which comprises two steel plates, core concrete, concrete-filled steel tubes (CFSTs), which act as boundary members, and steel truss connectors. Truss connectors decrease the out-of-plane deformation that affects the steel plates, and due to the resultant connection and constraint effects, the truss connectors enhance the bearing capacity of the wall. This paper briefly introduces the quasi-static test of five full-scale rectangular double-skin truss-reinforced composite shear wall specimens. The specimen exhibited shear compression failure with an aspect ratio of 2.0, and flexure shear failure occurred when the aspect ratio exceeded 2.0. Based on the analysis of actual stress state of the steel web and actual working performance of the infilled concrete, the shear strength and flexure strength design formulas of double-skin truss-reinforced composite shear wall were established. Comparison results with 26 specimens demonstrate that the design formulas exhibit remarkable accuracy, as most errors are within 20 % and 25 %, respectively. Which provide a preliminary sectional strength design proposal for the double-skin truss-reinforced composite shear wall.

Experimental and theoretical investigation of aortic wall tissue in tensile tests.

Understanding the mechanical properties of aortic tissue is essential for developing numerical computation tools and assessing the risk of aortic aneurysm fractures. Tensile tests using aortic wall specimens allow for the determination of stress and strain depending on the location and direction of the sample. The aim of this study was to perform a mechanical tensile test using canine aorta samples and create a numerical model of aortic tissue tension from the processed data. Dogbone-shaped samples were dissected from canine aortic segments. The initial measurements were made at zero tension and the tensile tests were conducted at 10 mm/min until rupture. Force and stretch data were used to obtain engineering and true stress-strain curves. The true stress-strain curves were taken until the maximum strength was obtained, after which they were smoothed and fitted using a logistic function with three coefficients. These curves were then used as material mechanical properties for a numerical model of the aortic tissue tension. A simplified rectangle form was used to mimic the middle of the dogbone-shaped portion of the tissue specimen. Experimental displacement data were collected for the boundary conditions of the finite element 3D model. The experimental data processing revealed that the logistic function described the nonlinear behaviour of the aorta soft tissue with an accuracy of 95% from the start of the tension to the media layer rupture. By applying numerical simulations, we obtained a correspondence of the load curve with an RMSE = 0.069 for the theoretical and experimental external tension data. The numerical investigation confirmed that the non-linear soft tissue was validated by applying a logistic function approach to the mechanical properties of the aortic wall.

Experimental Study on Structural Performance of Cast-in-Place Frame Printed Concrete Wall

A growing number of nations and regions have printed concrete structures thanks to the application of 3D printing technology in the field of civil engineering. However, the houses built with printed concrete are mostly printed concrete wall structures with composite load-bearing walls and cast-in-place frames. This structure solely takes into account the performance of the structure under vertical loads, which does not address its ability to withstand horizontal loads. In this paper, wall specimens were designed and tested under horizontal reciprocal loads in order to investigate the structural performance of this cast-in-place border-frame printed concrete wall structure under horizontal loads. Four factors are examined in order to determine how well the cast-in-place frame printed concrete wall structure performs when subjected to horizontal loads: column longitudinal reinforcement strain, hysteresis curve, skeleton curve, and energy dissipation capacity. According to the test results, the addition of the wall increased the bearing capacity and accumulated energy dissipation of the specimen, but the increase in stiffness also caused the structural ductility to decrease. As a result, cracks were more likely to generate at the wall–column joints, so the stiffness matching between the printed concrete wall and the cast-in-place side frame needed to be further coordinated to obtain a higher ductility. It turns out that the wall sections have little impact on the seismic performance of the members.

Developing of reinforced grouting mortar tenon and pseudo-static experimental test for seismic performance of precast shear wall

A high-performance grouting mortar is applied to the wall joint to improve the seismic performance of the precast shear wall. This study proposes a configuration and synchronous grouting construction method for preparing reinforced high grouting mortar tenons. Three precast shear wall specimens with the prepared tenon and one common precast comparison specimen were tested with pseudo-static experiments, and the experimental results, i.e., failure process and mode, hysteretic and skeleton curves, capacities, stiffness and ductility, were analyzed. The results showed that the failure mode of precast shear wall specimens with reinforced tenon belonged to bending-shear failure. The reinforced tenon increased the strength capacity, stiffness, and energy dissipation ability and the reinforced tenon joints achieved strength capacity equivalent to a common precast shear wall. The tenon height and axial ratio significantly influenced the mechanical properties of stiffness, ductility, and energy dissipation. Which is, the tenon height should be reasonably controlled for shear transfer considerations, and the specimens with higher axial ratio showed better performance.

Experimental study and mechanism analysis of out-of-plane seismic performance of reinforced concrete shear walls

Compared with the in-plane seismic performance, the out-of-plane seismic performance of reinforced concrete shear walls is weak and usually neglected, which leads to an inadequate study of the out-of-plane damage mechanism of shear walls and a lack of clear protective measures. In order to compare the similarities and differences in seismic performance of reinforced concrete shear walls when subjected to in-plane and out-of-plane loads in different directions and to clarify the key influencing factors, low cyclic loading tests were carried out on typical shear wall specimens in both in-plane and out-of-plane directions. The moment-curvature simulations of shear wall sections in both in-plane and out-of-plane directions are analyzed. The effects of parameters such as axial pressure ratio, wall thickness, height to width ratio and concrete grade on in-plane and out-of-plane seismic performance were analyzed at the member level in combination with finite element variable parameter analysis; at the structural system level, the time history analysis of 2 frame shear wall structures for single seismic action and main-aftershock sequence is established, and the structural damage is evaluated through the maximum story drift and rotation. The results reveal that the out-of-plane seismic performance of shear walls is significantly weaker than their in-plane seismic performance, with a difference of 1/20∼1/15 times in bearing capacity, where wall thickness and aspect ratio are the main parameters affecting in-plane and out-of-plane seismic performance; when the shear walls in the structure are subjected to seismic action in the out-of-plane direction, their out-of-plane direction will undergo large deformation and damage will occur easily, especially in the Single directional wall with less structure. The out-of-plane nonlinear analysis of the cross-section can be performed more accurately and quickly by using the new principal structure model proposed in this manuscript and some traditional principal structures. In the seismic design of shear walls, both in-plane and out-of-plane seismic performance should be ensured, and the wall thickness and height to width ratio of shear walls should be reasonably controlled.

Rebar corrosion of fly-ASH mixed concrete according to the placing environment

In this study, RC mock-up wall specimens with fly ash were manufactured in normal and hot environments, and the effect of the quality of concrete surfaces on carbonation and corrosion of rebars was compared and reviewed. As a result, the density of the surface of the wall specimen placed in a hot environment is lower than that of the normal environment, so the rate of carbonation is accelerated. That tendency accelerates as the replacement rate of fly ash increases, but the depth of carbonation in the normal environment is similar to that of NPC up to 20% of the replacement rate of fly ash, and the half-cell potential value and polarization resistance value of rebars were the same or higher. However, if the addition rate of fly ash is excessive, the depth of carbonation of concrete became very large regardless of the construction environment, so the corrosion rate of rebar also increased rapidly.