Experimental Study on the Seismic Mechanism of Full-scale Specimens of Superimposed Slab Shear Walls with Innovative Construction Details

Hongkang Zhao,Yaping Dai,Jun Yang,Youzhen Fang,Chengjie Mi,Lingchen Yang,Guojian Li 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.6

The seismic performance of precast reinforced concrete structures has long been a source ofconcern that impedes their use in seismic regions and high-rise buildings. To further optimizethe reinforcement configuration and enhance the seismic performance of the superimposedslab shear wall structures, this research proposed a superimposed slab shear wall withinnovative construction details. Five innovative superimposed slab shear walls and one cast-inplaceconcrete shear wall were designed and tested under low cycle lateral load. The effect ofaxial compression was considered during tests and analyses as well. In this paper, the seismicperformance, including failure mode, hysteretic behavior, load-bearing capacity, lateralstiffness degradation, energy dissipation, and seismic ductility was investigated and analyzed. The experimental results showed that five innovative superimposed slab shear walls and onecast-in-place concrete shear wall exhibited a similar failure mode of flexural-shear failure, anda large area of concrete was damaged and crushed at the shear wall corner. However, the areaof crushing concrete in the cast-in-place concrete shear wall was relatively small. And the areaof crushing concrete in the superimposed slab shear walls increased with the axial compressionratio. For the superimposed slab shear walls, the development of concrete cracks decreasedgradually with the enlargement in the axial compression ratio, while the length of the cracksincreased in this respect. The results indicated that innovative superimposed slab shear wallshad a higher strength capacity and lower lateral-resistant stiffness than the cast-in-placeconcrete shear wall. With the enlargement in the axial compression ratio, the peak strengthcapacity of the superimposed slab shear wall increased obviously, while it degraded rapidlyafter the peak load. It is suggested that the contribution of axial compression to the shear resistcapacity of the inclined section should not be considered in practical design. Meanwhile, theductility coefficients of the six specimens were larger than 2.2, which was in accordance withthe seismic requirements. This investigation could provide effective experimental data forfuture structural seismic performance evaluations and applications of precast superimposedslab shear wall structures.

Lateral Resistance of Reinforced Light-Frame Wood Shear Walls

이형우,장상식 한국목재공학회 2023 목재공학 Vol.51 No.1

In light-frame timber construction, the shear wall is one of the most important components that provide resistance to lateral loads such as earthquakes or winds. According to KDS (Korea Design Standard) 42 50 10, shear walls are to be constructed using wood-based structural sheathing, with studs connected by 8d nails spaced 150 mm along the edge and 300 mm in the field. Even though small-scale residential timber building can be designed to exhibit seismic resistance using light-frame timber shear walls in accordance with KDS 42 50 10, only the abovementioned standard type of timber shear wall is available. Therefore, more types of timber shear walls composed of various materials should be tested to measure their seismic resistance, and the results should be incorporated into the future revision of KDS 42 50 10. In this study, the seismic resistance of shear walls composed of structural timber studs and wood-based structural sheathing with reinforced nailing is tested to evaluate the effects of the reinforcement. For the nailing reinforcement, shear wall specimens are constructed by applying nail spacings of 75–150 mm and 50–100 mm. For the shear wall specimens with one sheathing and reinforced nailing, the shear strengths are 1.7–2.0 times higher than that of the standard shear wall (nail spacing of 150–300 mm). The shear strength of the shear walls with sheathing on both sides is 2.0–2.7 times higher than that of the standard shear wall.

Effects of Stud Spacing, Sheathing Material and Aspect-ratio on Racking Resistance of Shear Walls

장상식 한국목재공학회 2002 목재공학 Vol.30 No.3

This study was carried out to obtain basic information on racking resistance of shear walls and the factors affecting racking resistance of shear walls. Shear walls constructed by larch lumber nominal 50 mm×100 mm framing and various sheathing materials were tested by applying monotonic and cyclic load functions. Shear walls with various stud spacing such as 305 mm, 406 mm, and 610 mm were tested under both of monotonic and cyclic loads and shear walls with various aspect (height-width) ratios were tested under cyclic load functions. The effect of hold-down connectors in shear walls was also tested under cyclic load functions. Racking resistance of shear walls has very close linear relation with stud spacing and width of shear walls. The ultimate racking strength of shear walls was reached at around or before the displacement of 20 mm. It was proposed in this study that the minimum racking strength and minimum width for shear wall be 500 kgf and 900 mm, respectively. Load-displacement curves obtained by racking tests under monotonic load functions can be represented by three straight line segments. Under cyclic load functions, envelope curves can be divided into three sections that can be represented by straight lines and the third section showed almost constant or decreasing slope.

Integrating of Nonlinear Shear Models into Fiber Element for Modeling Seismic Behavior of Reinforced Concrete Coupling Beams, Wall Piers, and Overall Coupled Wall Systems

Ke Du,Huan Luo,Jiulin Bai,Jingjiang Sun 한국콘크리트학회 2019 International Journal of Concrete Structures and M Vol.13 No.5

Reinforced concrete (RC) coupled wall systems, compared with RC shear wall without opening, have more com-plex nonlinear behavior under the extreme earthquake loads due to the existence of coupling beams. The behavior characteristics induced by nonlinear shear deformation such as shear–flexure interaction, pinching effect, strength and stiffness deterioration are clearly observed in numerous cyclic tests of RC coupling beams and shear walls. To develop an analytical model capable of accurately and efficiently assessing the expected seismic performance of RC coupled wall systems, it is critical to define the appropriate key components models (i.e., nonlinear models of RC wall piers/shear walls and coupling beams). Classic fiber beam element based on the theory of Euler–Bernoulli beam is frequently adopted to simulate the nonlinear responses of slender RC wall piers and coupling beams in the literature because it is able to accurately model the response characters from interaction of axial–bending moment at the section level. However, classic fiber beam element cannot capture the nonlinear behaviors of non-slender structures mainly controlled by nonlinear shear deformation. To overcome this shortcoming, a modified force-based fiber element (MFBFE) including shear effect is introduced and used as the analysis element of non-slender RC coupling beams and shear walls. At the section level, a novel shear model for RC coupling beams and an existed shear model for RC shear walls are respectively added to this fiber element to simulate nonlinear responses of these two key components. The analytical model for RC coupled walls hence is formed through integrating the proposed models of these two key components. The validations with different experimental results of cyclic tests including key compo-nents and structural system reported in the literature using these proposed models are performed. Good agreements are achieved for all of these proposed models via comparisons between predicted results and experimental data.

섬유(Fiber)요소와 비선형 전단스프링을 적용한 고축력을 받는 철근콘크리트 전단벽의 비선형거동 분석

전대한 한국지진공학회 2015 한국지진공학회논문집 Vol.19 No.5

Reinforced concrete shear walls are effective for resisting lateral loads imposed by wind or earthquakes. Observed damages of the shear wall in recent earthquakes in Chile(2010) and New Zealand(2011) exceeded expectations. Various analytical models have been proposed in order to incorporate such response features in predicting the inelastic response of RC shear walls. However, the model has not been implemented into widely available computer programs, and has not been sufficiently calibrated with and validated against extensive experimental data at both local and global response levels. In this study, reinforced concrete shear walls were modeled with fiber slices, where cross section and reinforcement details of shear walls can be arranged freely. Nonlinear analysis was performed by adding nonlinear shear spring elements that can represent shear deformation. This analysis result will be compared with the existing experiment results. To investigate the nonlinear behavior of reinforced concrete shear walls, reinforced concrete single shear walls with rectangular wall cross section were selected. The analysis results showed that the yield strength of the shear wall was approximately the same value as the experimental results. However, the yielding displacement of the shear wall was still higher in the experiment than the analysis. The analytical model used in this study is available for the analysis of shear wall subjected to high axial forces.

Evaluation and Improvement of Deformation Capacities of Shear Walls Using Displacement-Based Seismic Design

Oh, Young-Hun,Han, Sang-Whan,Choi, Yeoh-Soo Korea Concrete Institute 2006 International Journal of Concrete Structures and M Vol.18 No.e1

RC shear walls are frequently used as lateral force-resisting system in building construction because they have sufficient stiffness and strength against damage and collapse. If RC shear walls are properly designed and proportioned, these walls can also behave as ductile flexural members like cantilevered beams. To achieve this goal, the designer should provide adequate strength and deformation capacity of shear walls corresponding to the anticipated deformation level. In this study, the level of demands for deformation of shear walls was investigated using a displacement-based design approach. Also, deformation capacities of shear walls are evaluated through laboratory tests of shear walls with specific transverse confinement widely used in Korea. Four full-scale wall specimens with different wall boundary details and cross-sections were constructed for the experiment. The displacement-based design approach could be used to determine the deformation demands and capacities depending on the aspect ratio, ratio of wall area to floor plan area, flexural reinforcement ratio, and axial load ratio. Also, the specific boundary detailing for shear wall can be applied to enhance the deformation capacity of the shear wall.

Structural Shear Wall Systems with Metal Energy Dissipation Mechanism

Li, Guoqiang,Sun, Feifei,Pang, Mengde,Liu, Wenyang,Wang, Haijiang Council on Tall Building and Urban Habitat Korea 2016 International journal of high-rise buildings Vol.5 No.3

Shear wall structures have been widely used in high-rise buildings during the past decades, mainly due to their good overall performance, large lateral stiffness, and high load-carrying capacity. However, traditional reinforced concrete wall structures are prone to brittle failure under seismic actions. In order to improve the seismic behavior of traditional shear walls, this paper presents three different metal energy-dissipation shear wall systems, including coupled shear wall with energy-dissipating steel link beams, frame with buckling-restrained steel plate shear wall structure, and coupled shear wall with buckling-restrained steel plate shear wall. Constructional details, experimental studies, and calculation analyses are also introduced in this paper.

Analysis of Reinforced Concrete Shear Walls with Single Band of Octagonal Openings

Abdul Kadir Marsono,Somaieh Hatami 대한토목학회 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.5

The applications of cast-in-situ reinforced concrete shear walls for tall buildings are prevalent in many countries. Shear walls with openings are called coupled shear walls which act as cantilevered walls joined by coupling beams. Openings for windows and doors affect the behaviour of the structure and cause to decrease the strength of shear wall. Some methods were suggested in the past to increase the strength of shear wall but they are not easy to apply and need labour attentiveness. This study proposes adding haunches to the corners of rectangular openings as a simple method to increase the strength of coupled shear wall structures. Analytical analysis employing Total Moment Concept and Continuous Connection Method (CCM) and Nonlinear Finite Element Analysis (NLFEA) were carried out on symmetrical shear walls with single band of octagonal openings. The results are compared with outputs of previous study on shear wall with rectangular openings. The analysis results demonstrated that it is confidently worth to use the octagonal openings due to very small percentage increase in the total weight of the structure compared with the amount increase in ultimate load of the shear walls.

Investigations on the Shear Mechanism of Steel-Tube-Reinforced Concrete Shear Walls with a Low Shear-Span Ratio

Liang Bai,Cai Zhang,Ergang Xiong 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.7

This paper describes the study of steel tube reinforced concrete (STRC) shear walls with a low shear-span ratio, in which steel tubes are embedded in the web of the shear wall. The addition of these steel tubes can significantly improve the shear behavior of ordinary RC shear walls. A series of cyclic loading tests allow us to examine the failure mode, hysteretic behavior, deformability, and energy dissipation capacity of the STRC shear walls. The investigation indicate the STRC shear walls transform from entire section walls to walls with vertical slits under loading. This prevents brittle shear failure and improves the deformation and energy dissipation capacity of the specimens. A softened strut-and-slip model is applied to analyze the shear mechanism of STRC shear walls, and is shown to predict the shear capacity accurately.

Experimental and numerical study on mechanical behavior of RC shear walls with precast steel-concrete composite module in nuclear power plant

Xu Haitao,Xu Jinbin,Dong Zhanfa,Ding Zhixin,Bai Mingxin,Du Xiaodong,Wang Dayang 한국원자력학회 2024 Nuclear Engineering and Technology Vol.56 No.6

Reinforced concrete (RC) shear walls with precast steel-concrete composite modular (PSCCM) are strongly recommended in the structural design of nuclear power plants due to the need for a large number of process pipeline crossings and industrial construction. However, the effect of the PSCCM on the mechanical behavior of the whole RC shear wall is still unknown and has received little attention. In this study, three 1:3 scaled specimens, one traditional shear wall specimen (TW) and two shear wall specimens with the PSCCM (PW1, PW2), were designed and investigated under cyclic loadings. The failure mode, hysteretic curve, energy dissipation, stiffness and strength degradations were then comparatively investigated to reveal the effect of the PSCCM. Furthermore, numerical models of the RC shear wall with different PSCCM distributions were analyzed. The results show that the shear wall with the PSCCM has comparable mechanical properties with the traditional shear wall, which can be further improved by adding reinforced concrete constraints on both sides of the shear wall. The accumulated energy dissipation of the PW2 is higher than that of the TW and PW1 by 98.7 % and 60.0 %. The failure of the shear wall with the PSCCM is mainly concentrated in the reinforced concrete wall below the PSCCM, while the PSCCM maintains an elastic working state as a whole. Shear walls with the PSCCM arranged in the high stress zone will have a higher load-bearing capacity and lateral stiffness, but will suffer a higher risk of failure. The PSCCM in the low stress zone is always in an elastic working state.