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Out-of-plane buckling of shear walls under seismic action (a) sketch of wall observed in 

Out-of-plane buckling of shear walls under seismic action (a) sketch of wall observed in 

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Article
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A special class of RC shear wall is identified with short shear span, attributed to the high coupling degree in the elastic design of tall buildings located in low-to-moderate seismicity regions. The short shear span characteristic precludes plastic hinge formation and increase the susceptibility of shear failure during seismic events. It is noted...

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Context 1
... arch resistance model [Yang et al., 2015] was proposed to evaluate the residual axial load carrying capacity of RC columns. The model was based on the sound theory of structural mechanics by extending the shear friction model [Wallace et al., 2008] to confined concrete with partially crushed core. However, the study did not consider buckling of the vertical reinforcement prior to axial collapse which contradicts the experimental evidence in the extant literature . Fig. 3 shows the out-of-plane buckling of shear walls observed in the Christchurch earthquake and experiments carried out by the authors . Similar out-of-plane buckling was experimentally observed by others (see [Goodsir, 1985;Rosso et al., 2016]). By examining the axial collapse of walls through the conventional energy method or kinematic relations (similar to the formulation by Euler [1759] for structurally unstable critical load in columns), it is postulated that axial collapse is closely associated with out-of-plane buckling under in-plane cyclic loading with the presence of axial loading. The distinct effects of the p/v ratio for categorising the failure mode associated with out-of-plane buckling are schematically shown in Fig. 4. When p/v < 2, tensile stress is present which indicates that the wall may experience cyclic inelastic tension-compression excursions (see Fig. 4(a)). When p/v ≥ 2, the applied ALR is two times larger than the normalised shear stress, and the entire wall experiences cyclic compression-compression loading with elastic recoverable tensile strain (see Fig. 4(b)). Underlying this assumption are three key mechanical models developed for out-of-plane buckling, namely: (i) Paulay and Priestley [1993] (hereinafter PP-93), (ii) Chai and Elayer [1999] (hereinafter CE-99) and (iii) Parra and Moehle [2017] (hereinafter ...
Context 2
... arch resistance model [Yang et al., 2015] was proposed to evaluate the residual axial load carrying capacity of RC columns. The model was based on the sound theory of structural mechanics by extending the shear friction model [Wallace et al., 2008] to confined concrete with partially crushed core. However, the study did not consider buckling of the vertical reinforcement prior to axial collapse which contradicts the experimental evidence in the extant literature . Fig. 3 shows the out-of-plane buckling of shear walls observed in the Christchurch earthquake and experiments carried out by the authors . Similar out-of-plane buckling was experimentally observed by others (see [Goodsir, 1985;Rosso et al., 2016]). By examining the axial collapse of walls through the conventional energy method or kinematic relations (similar to the formulation by Euler [1759] for structurally unstable critical load in columns), it is postulated that axial collapse is closely associated with out-of-plane buckling under in-plane cyclic loading with the presence of axial loading. The distinct effects of the p/v ratio for categorising the failure mode associated with out-of-plane buckling are schematically shown in Fig. 4. When p/v < 2, tensile stress is present which indicates that the wall may experience cyclic inelastic tension-compression excursions (see Fig. 4(a)). When p/v ≥ 2, the applied ALR is two times larger than the normalised shear stress, and the entire wall experiences cyclic compression-compression loading with elastic recoverable tensile strain (see Fig. 4(b)). Underlying this assumption are three key mechanical models developed for out-of-plane buckling, namely: (i) Paulay and Priestley [1993] (hereinafter PP-93), (ii) Chai and Elayer [1999] (hereinafter CE-99) and (iii) Parra and Moehle [2017] (hereinafter ...
Context 3
... The model was based on the sound theory of structural mechanics by extending the shear friction model [Wallace et al., 2008] to confined concrete with partially crushed core. However, the study did not consider buckling of the vertical reinforcement prior to axial collapse which contradicts the experimental evidence in the extant literature . Fig. 3 shows the out-of-plane buckling of shear walls observed in the Christchurch earthquake and experiments carried out by the authors . Similar out-of-plane buckling was experimentally observed by others (see [Goodsir, 1985;Rosso et al., 2016]). By examining the axial collapse of walls through the conventional energy method or kinematic ...

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Citations

... These walls are typically found in buildings constructed prior to the mid-1970s; however, limited data existed to calibrate and validate the model. Looi and Su (2018) formulated a model based on Mohr's circle to assess axial failure of heavily reinforced, short shear-span RC coupled shear walls, designed for moderate-intensity earthquake ground shaking and primarily used to control lateral drift in strong wind events. Results from recent test programs (e.g., Alarcon et al. 2014;Hube et al. 2014;Segura and Wallace 2018;Dashti et al. 2017;Shegay et al. 2018;Zhang 2019) have revealed that axial failure occurs in flexure-controlled walls with special and ordinary detailing, and that axial failure mechanisms include complex phenomena that are influenced by various parameters. ...
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A large number of reinforced concrete (RC) buildings constructed prior to the mid-1970s in earthquake-prone regions rely on lightly reinforced or perforated, perimeter structural walls to resist earthquake-induced lateral loads. These walls are susceptible to damage when subjected to moderate-to-strong shaking; a number of such cases were observed in past earthquakes. Despite these observations, there have been limited studies reported in the literature to investigate the loss of axial (gravity) load carrying capacity of damaged walls and wall piers, primarily due to limited experimental data. This study utilizes a comprehensive database that includes detailed information on more than 1100 RC wall tests. To study wall axial failure, the database was filtered to identify and analyze datasets of tests on shear- and flexure-controlled walls. The findings indicated that axial failure occurs in flexure-controlled walls with special and ordinary detailing, and that axial failure mechanisms include complex phenomenon influenced by various parameters. For diagonal shear-controlled walls, axial failure results from sliding along a critical crack plane extending diagonally over the height of the wall when the shear friction demand exceeds the shear friction capacity. Based on the results, expressions were developed to predict lateral drift capacity at axial failure of RC walls and piers.
... The authors had carried out experiments on the axial collapse (beyond shear failure) of the short shear span walls with concurrent axial permanent actions and lateral seismic actions in Looi et al. [6]. Based on the observation during the experiments and the post-processed results of test data, the Modified Mohr's Axial Capacity Model (MMACM) was recently developed in Looi and Su [7] for walls with axial-toshear stress ratio of less than 2 (p/v < 2). This paper introduces the use of the MMACM model on a tall RC building with transfer structure in Malaysia, considering the seismic actions for Malaysia proposed in Looi et al. [8], together with the spectral shape of Model B adopted in the Malaysia National Annex (NA) for Eurocode 8 (EC8) [9]. ...
... For Figure 3(c), the applied axial stress (p) is more critical at the wall edge and should be added with the vertical component of the diagonal shear stress coming from the lateral seismic actions, assuming an angle correspond to the SLR. Readers of this article are suggested to refer to those original articles [6,[12][13] and the concise summary in Looi and Su [7]. ...
... By using the MMACM in Equation 1, wall P102 and P121 were identified. Wall P102 has a p/v < 2 and wall P121 is with p/v > 2. Wall with p/v < 2 may experience cyclic tension-compression excursion at the wall edge prior to collapse [7]. Wall P102 was found reaching its peak diagonal shear capacity with a utilisation ratio of 0.95 but survived in the seismic axial collapse check with utilisation ratio of 0.60. ...
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A special class of short shear span RC shear wall exists in the form of a sub-structure at the base of slender walls in tall buildings, was found common in the low-to-moderate seismicity region. These non-seismically designed short shear span RC walls are highly stressed in axial load under gravity and lateral actions, and have limited deformability. Thus, there is a need for structural engineers to re-examine the seismic performance of this special class of short shear span RC walls under a rare earthquake event. Recently, a Modified Mohr's Axial Capacity Model (MMACM) was developed by the authors to estimate the axial load capacity of these walls prior to axial collapse after shear failure. The model underpinned the assumption of seismic axial collapse of these walls is closely associated with out-of-plane buckling. A numerical example of a RC building with transfer structure in Malaysia, subject to seismic loading is modelled to demonstrate the use of the MMACM in estimating seismic axial collapse of short shear span RC shear walls.
... The authors had carried out experiments on the axial collapse (beyond shear failure) of the short shear span walls with concurrent axial permanent actions and lateral seismic actions in Looi et al. [6]. Based on the observation during the experiments and the post-processed results of test data, the Modified Mohr's Axial Capacity Model (MMACM) was recently developed in Looi and Su [7] for walls with axial-to-shear stress ratio of less than 2 (p/v < 2). This paper introduces the use of the MMACM model on a tall RC building with transfer structure in Malaysia, considering the seismic actions for Malaysia proposed in Looi et al. [8], together with the spectral shape of Model B adopted in the Malaysia National Annex (NA) for Eurocode 8 (EC8) [9]. ...
... For Figure 3(c), the applied axial stress (p) is more critical at the wall edge and should be added with the vertical component of the diagonal shear stress coming from the lateral seismic actions, assuming an angle correspond to the SLR. Readers of this article are suggested to refer to those original articles [6,[12][13] and the concise summary in Looi and Su [7]. ...
... By using the MMACM in Equation 1, wall P102 and P121 were identified. Wall P102 has a p/v < 2 and wall P121 is with p/v > 2. Wall with p/v < 2 may experience cyclic tension-compression excursion at the wall edge prior to collapse [7]. Wall P102 was found reaching its peak diagonal shear capacity with a utilisation ratio of 0.95 but survived in the seismic axial collapse check with utilisation ratio of 0.60. ...
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Full-text available
A special class of short shear span RC shear wall exists in the form of a sub-structure at the base of slender walls in tall buildings, was found common in the low-to-moderate seismicity region. These non-seismically designed short shear span RC walls are highly stressed in axial load under gravity and lateral actions, and have limited deformability. Thus, there is a need for structural engineers to re-examine the seismic performance of this special class of short shear span RC walls under a rare earthquake event. Recently, a Modified Mohr’s Axial Capacity Model (MMACM) was developed by the authors to estimate the axial load capacity of these walls prior to axial collapse after shear failure. The model underpinned the assumption of seismic axial collapse of these walls is closely associated with out-of-plane buckling. A numerical example of a RC building with transfer structure in Malaysia, subject to seismic loading is modelled to demonstrate the use of the MMACM in estimating seismic axial collapse of short shear span RC shear walls.
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Reinforced concrete (RC) structural walls (also known as shear walls) have commonly been used as lateral force-resisting elements in buildings in regions of moderate-to-high seismic hazard because they provide substantial lateral strength and stiffness against ground shaking. A large number of reinforced concrete (RC) buildings constructed prior to the mid-1970s in earthquake-prone regions rely on lightly reinforced or perforated, perimeter structural walls to resist earthquake-induced lateral loads. These walls are susceptible to extensive damage when subjected to moderate-to-strong shaking; a number of such cases were observed in the 1995 Kobe, 1999 Chi-Chi, and 1999 Kocaeli earthquakes, and more recently in 2010 Maule and 2011 Christchurch earthquakes. Despite these observations, only limited studies are reported in the literature that investigate the topic of loss of axial (gravity) load carrying capacity of damaged walls and wall piers, primarily due to the lack of experimental data. Furthermore, wall axial failure could trigger partial or total building collapse, especially in buildings with significant torsional irregularities and low redundancy. The lack of data may also result in conservatively low estimates of lateral drift capacity at axial failure for ASCE 41 acceptance criteria, which would result in very intrusive and costly seismic retrofit schemes. To address this issue, a comprehensive database, known as UCLA-RCWalls database, was developed that includes detailed information on more than 1100 RC wall tests surveyed from more than 260 experimental programs. To study axial collapse of structural walls and wall piers, the database was filtered to identify and analyze datasets of tests on shear-and flexure-controlled walls. Based on the results, and previously reported models, expressions were derived to predict lateral drift capacity at axial failure of walls and wall piers.
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This document lists all the references where information and data on the wall tests in the UCLA-RCWalls Database was reported and that were available to the authors. The database currently contains over 1100 wall tests reported in the literature around the world.