Ultimate Compressive Capacity Research Articles

Residual compressive strength of locally corroded circular CFST stub columns: An experimental study

Abstract Circular concrete-filled steel tubular (CFST) columns are widely used in civil engineering structures due to their high strength, stiffness, and ductility. However, these columns are susceptible to local corrosion damage, which can reduce their load-carrying capacity and durability. This paper presents an experimental investigation of the impact of local corrosion on the residual compressive strength of CFST stub columns. The experimental program included 9 CFST columns, which were divided into two groups: G1 and G2. G1 specimens were subjected to actual electrochemical corrosion, while G2 specimens were subjected to mechanical damage to simulate the corrosion effect. The experimental results included the tested columns’ corrosion profiles, failure modes, load-strain relationships, and load-carrying capacities. The main findings of this paper show that: (1) Different heights and thicknesses of corrosion profile representing the non-uniform localized corrosion. (2) Failure modes were mainly affected by the localized damage conditions, where the buckling occurred in the affected area. (3) Load-strain relationships exhibited elastic behavior initially, followed by nonlinear plastic behavior until reaching their ultimate compressive capacity. (4) The mechanical damage method can reasonably approximate the corrosion damage in CFST columns. This paper provides useful insights into the structural behavior of locally damaged CFST short columns.

Axial performance of square steel tube and sandwiched concrete jacketed circular CFST columns

Although extensive experimental and numerical studies have been conducted on the axial performance of steel tube and sandwiched concrete jacketed CFST columns, contableurations with outer square tubes and inner circular CFST components are rarely found. This paper investigates the axial performance of square steel tube and sandwiched concrete jacketed circular CFST columns, examining the effects of outer steel ratio and sandwiched concrete strength on failure patterns, relative load-strain curves, and load-bearing capacity. The analysis of ultimate compressive capacity confirmed the effective confinement provided by the outer square steel tube. Based on the experimental results, a finite element model was established to further study the working mechanism of retrofitted columns. The load on components, distribution of longitudinal stress and transverse constraint stress on concrete revealed that the inner concrete experiences dual confinement effects from both inner and outer steel tubes, with the constraint of the outer square steel tube becoming significant only during the load dropping phase. Furthermore, a simple equation was proposed for predicting the axial compressive load-bearing capacity of retrofitted columns using superposition methods and design codes. Comparison results demonstrated good agreement between experimental and calculated values.

Performance of multi-ribbed composite wall incorporating reactive powder concrete-filled steel tubular columns under axial compression

In this study, axial compression researches of an innovative composite shear wall, named multi-ribbed composite wall incorporating reactive powder concrete-filled steel tubular columns, were conducted using theoretical analyses as well as experimental and numerical investigations. This precast hybrid system embedded reactive powder concrete-filled steel tubular columns as boundary elements of multi-ribbed composite wall. A novel approach, namely the unified strength theory, was adopted in consideration of various materials diversity. The outcomes of unified strength theory were utilized to predict the ultimate compressive capacity of multi-ribbed composite wall equipped with reactive powder concrete-filled steel tubular columns. The proposed theoretical formulas were validated against the experimental results reported in this paper. Despite the fact that the calculated formula with b= 0 was obtained to predict the closest capacity value of the test specimen infilling ordinary concrete. The calculations with different values of b clearly indicated that the intermediate principal stress effect should be rationally considered. Experimental observations suggested that the frame column significantly contributed to improving the compressive performance throughout the entire process and maintained the wall integrity. Meanwhile, finite element models were developed using the ABAQUS program, followed by the elaboration of its numerical implementation. The numerical predictions of ten shear wall specimens infilling reactive powder concrete were found to be reasonably in agreement with the calculated results corresponding to b= 0.5. These findings revealed the characteristics of multiple defensive lines of "block-ribbed column-frame column" under axial compression. Following the successful validation of finite element models, parametric studies were carried out to evaluate the influences of the filled block compressive strength, steel tube wall thickness and height-width ratio. The results show that the axial compression capacity of multi-ribbed composite wall incorporating reactive powder concrete-filled steel tubular columns can be noticeably improved with an increase in block strength and tube thickness. The proposed composite wall demonstrates favorable cooperative working performance and desirable displacement ductility. Subsequently, the primary objective of this pilot study aimed at developing a reliable theoretical calculation formula and conducting numerical simulation verification of the innovative composite wall. The aforementioned conclusions are intended to provide insights for the guidance and optimization of engineering structures.

Analytical Solution for the Ultimate Compression Capacity of Unbonded Steel-Mesh-Reinforced Rubber Bearings

Unbonded steel-mesh-reinforced rubber bearings (USRBs) have been proposed as an alternative isolation bearing for small-to-medium-span highway bridges. It replaces the steel plate reinforcement of common unbonded laminated rubber bearings (ULNR) with special steel wire meshes, resulting in improved lateral properties and seismic performance. However, the impact of this novel steel wire mesh reinforcement on the ultimate compression capacity of USRB has not been studied. To this end, theoretical and experimental analysis of the ultimate compression capacity of USRBs were carried out. The closed-form analytical solution of the ultimate compression capacity of USRBs was derived from a simplified USRB model employing elasticity theory. A parametric study was conducted considering the geometric and material properties. Ultimate compression tests were conducted on 19 USRB specimens to further calibrate the analytical solution, considering the influence of the number of reinforcement layers. An efficient solution for USRBs’ ultimate compression capacity was obtained via multilinear regression of the calibrated analytical results. The efficient solution can simplify the estimation of USRBs’ ultimate compression capacity while maintaining the same accuracy as the calibrated solution. Based on the efficient solution, the design process of a USRB with a specific ultimate compression capacity was illustrated.

Exploring key factors affecting the ultimate compression capacity of Unbonded Steel-mesh-reinforced Rubber Bearings

To address bearing-sliding damage in highway bridges during seismic events, the Unbonded Steel-mesh-reinforced Rubber Bearing (USRB) was developed. This novel bearing employs flexible, high-strength steel wire meshes as reinforcement, enhancing lateral deformation capacity and reducing bearing-sliding risk. Recent seismic specifications increased the bearings' vertical design load to 30 MPa, where existing bearings with flexible reinforcements (e.g., fiber-reinforced bearings) fail to meet this standard. Hence, for the first time, our study thoroughly investigated the ultimate compression capacity of USRBs and the key factors influencing the capacity. Through ultimate compression tests on full-scale prototypes, we demonstrated that USRBs can comply with heightened seismic requirements, with primary failure attributed to the tensile failure of the steel mesh reinforcement. These tests were complemented by 3D finite element modeling in ANSYS, employing the LINK180 elements for mesh reinforcement and defining the ultimate capacity as the point at which reinforcement stress reached tensile strength. This particular modeling approach, validated against experimental data, can accurately predict the ultimate compression capacity and the force-deformation response of USRBs. A comprehensive parametric analysis, using the validated modeling approach and an advanced statistical method LHS-PRCC, was conducted to identify the key factors influencing the compressive capacity, including bearing geometric parameters (i.e., bearing width, the second shape factor, and rubber layer thickness), steel-mesh configuration characteristics, and steel-mesh material properties. Our findings emphasize the significance of rubber layer thickness, steel mesh weight, and steel wire tensile strength and strain in influencing the USRBs' ultimate compression capacity. Based on these key factors, an empirical equation for the ultimate compression capacity of USRBs was established to guide the optimization design of USRBs. This study not only fills the gap in USRB's performance under extensive compression but also provides a foundation for future optimization of these bearings to enhance their performance in bridge engineering.

Steel-concrete composite adapter for wind turbine hybrid towers: Mechanism and ultimate capacity prediction under compression

The adapter is an essential part of the wind turbine hybrid tower since the steel and the prestressed concrete segments are connected by the adapter. Due to the large designed prestress, the adapter is prone to fail under compression. Consequently, the ultimate capacity of the adapter under compression is critical to the safe operation of the wind turbine. Previously, the steel–concrete composite adapter (SCCA) was presented and a relevant compressive test was conducted. It is necessary to further explore the ultimate behavior and develop the calculation method of SCCA. Therefore, a comprehensive analytical investigation on the ultimate compressive capacity of SCCA is conducted in this paper. Refined finite element models are built and validated based on the former test results. The mechanism analysis in terms of the stress distribution and the contact stress between steel tubes and sandwich concrete is carried out to reveal the ultimate compressive behavior of SCCA and the effects of studs, stiffened plates, and circumferential rebars. The accuracy and applicability of five existing calculation methods for the ultimate compressive capacity are evaluated. Lastly, a simplified practical method for predicting the ultimate compressive capacity of SCCA is proposed and it can provide reasonable predictions within the common range in wind turbine engineering.

Concrete-filled circular stainless-steel tubular columns subjected to low-temperature axial compression

This paper studied the compression behaviours of concrete-filled circular stainless-steel (SS) tubes (CFSSTs) used in the cold-region engineering constructions. Sixteen CFSSTs using SS 30408 tubes were firstly tested at varying low temperatures (T = 20, −30, −60, and −80 °C) related to the cold-region environments. The studied parameters in the testing programme are low temperatures (T) and wall-thickness of SS tube (t). Subjected to low-temperature compression, all CFSSTs failed in outward local buckling of SS tube and crushing of concrete. Most of the CFSSTs exhibits ductile compression behaviour without declining recession due to the excellent ductility of SS tube. The P-Δ curves of CFSSTs exhibit a linear elastic stage, a relative short nonlinear stage, and a long strength-hardening stage. The decreasing low temperature and increasing wall-thickness of SS tube significantly improved the compression behaviours of CFSSTs. The infilled concrete greatly improved the compression capacity and prevented inward local buckling of SS tubes in CFSSTs. This paper also developed finite element model (FEM) for compression-behaviour simulations of CFSSTs at low temperatures. Validations against 16 tests confirmed the FEM simulation accuracy. Different code prediction equations in AISC360, Eurocode 4, and AIJ were checked for predicting the ultimate compression capacity of CFSSTs at low temperatures. Finally, Eurocode 4 and AIJ were recommended after comparisons of predictions with test results.

Compression behavior of GFRP reinforced hybrid fibre reinforced concrete short columns subjected to eccentric loading

This paper presents the results of an experimental study carried out on the GFRP reinforced hybrid fibre concrete short columns subjected to eccentric compression. In this study, hybrid fiber-reinforced concrete was prepared in different volume ratios of hybrid fibers and the cooperative effect of the GFRP reinforcement and the steel-PVA hybrid fibre concrete with different fibre ratios under eccentric loading was explored. 10 GFRP reinforced hybrid fibre concrete short columns and 2 plain reinforced concrete short columns were tested to investigated their eccentric compressive properties. The tests results are presented in terms of failure modes, longitudinal reinforcement strain, concrete compressive strain and compressive load capacity of GFRP reinforced hybrid fibre concrete eccentrically compressed short columns. The results show that the concrete on the compressed side was crushed when the specimen under both the initial eccentricity of 50 mm and 100 mm the reinforcement were pulled on the tension side of specimen under a larger initial eccentricity of 100 mm. The addition of fibres can effectively prevent the crack generation and development and improve the bonding property between reinforcement and concrete. Besides, the addition of steel fibre contributes a better performance on the ultimate compressive capacity of specimen under a lager initial eccentricity with an optimal ratio of steel fibre at 1.4 %. PVA fibre effectively improve the ductility of the concrete, so that the hybrid fibre concrete elements remain relatively its integrity after failure. Finally, considering the effect of GFRP reinforcement and different ratios of steel fibre and PVA fibre on the compressive capacity of short concrete columns, the equation for the calculation of the ultimate compressive capacity of partial sections of eccentric columns is proposed, and a good agreement was observed between the tested and calculated value.

Prediction Method of Vertical Ultimate Compressive Bearing Capacity of Single Pile in Soft Soil considering the Influence of Gravity

Considering that the pile foundation is widely used in soft soil, in order to improve the prediction accuracy of the vertical ultimate compressive bearing capacity of a single pile, this paper puts forward a calculation model of the pile side friction resistance in homogeneous soil based on the previous research and further deduces the calculation method of pile body internal force in layered soil under the influence of gravity field. In this research, the transmission of load along the pile body is related to the previous research on the ultimate end resistance, and an analytical calculation for the vertical ultimate compressive capacity of a single pile is proposed. The novelty of the method is that the ultimate bearing capacity is solved from the perspective of force transfer while considering its own gravity, making the results more accurate. In order to verify the reliability of the method, four engineering test piles in the soft soil area of Suzhou, China, were selected, and it is indicated that the results of the static load test and finite element simulation are consistent with the proposed method, proving that the method proposed in this paper for predicting the vertical ultimate compressive bearing capacity of single pile in soft soil area has an excellent effect.

Axial compressive behavior of ultra‐high performance concrete‐filled double skin high‐strength steel tubular short columns

AbstractIn this paper, seven ultra‐high performance concrete (UHPC)‐filled double skin high‐strength steel tubular (UHPCFDST) columns and four UHPC filled high‐strength steel tubular (UHPCFST) columns axial compression tests were carried out. The effects of hollow ratio, width‐to‐thickness ratio of the outer steel tube, and cross‐section combination form on the axial compression performance of UHPCFDST were studied, and the failure mode, axial load–strain curve, and strain response were discussed. The results showed that the high‐strength steel tube had good compatibility with UHPC, and all specimens finally had serious buckling deformation. The peak load of UHPCFDST specimens decreased with the increase of the hollow ratio, the ductility and toughness were improved. The width‐to‐thickness ratio of the outer steel tube had the most significant effect on the axial compression performance of the specimens. With the increase of the width‐to‐thickness of the outer steel tube, the ductility of the specimens tended to increase, and the toughness index first increased and then decreased. Finally, a unified calculation model for the ultimate compressive capacity of UHPCFDST and UHPCFST specimens was proposed, and the predicted value was in good agreement with the experimental value.

Advanced numerical modelling for predicting residual compressive strength of corroded stiffened plates

An advanced methodology for predicting the residual compressive strength of corroded stiffened plates is developed here using the non-linear finite element method. The non-uniform loss of a plate thickness is accounted for on a macro-scale. In contrast, mechanical properties are changed using the constitutive model to reflect the corrosion degradation impact on a micro-scale. Three different stiffened plate thicknesses are considered, and ultimate compressive capacity is analysed for different severity of corrosion degradation. First, the deterministic analysis is performed, and numerical results are validated against the experiment. Then, the corrosion fields are modelled with the use of random fields. Different statistical characteristics of the generated random fields are investigated to identify their impact on the resulting structural behaviour. It was found that severe corrosion degradation could cause an excessive reduction of structural capacity even at 50%. Finally, the results of the present study are compared with the already studied corrosion models showing a highly non-conservative solution of the latter, where the plate thickness is reduced only due to the corrosion degradation progress.

Performance of square UHPC filled high-strength steel tubular columns under axial compression: Experiment and theory analysis

In this paper, 12 ultra-high performance concrete (UHPC) filled high-strength steel tubular (UHPCFST) short columns with square-section were subjected to axial compression tests. The effects of confinement factor (ξ) on the axial compression performance of UHPCFST were discussed, and the failure modes, axial load–strain curves, and strain responses were discussed. The results showed that the specimens mainly had two failure modes: shear failure and waist drum failure, and all specimens showed good ductility and high post-peak bearing capacity, indicating that high-strength steel tubes could provide higher restraint for UHPC and form a high-strength and high-performance steel-UHPC system. When ξ ≥ 1.42, the strength index (SI) increased significantly with the increase of ξ. When ξ ≤ 1.06, the SI was close to 1. With the increase of ξ, the ductility and toughness of the specimens were improved. Finally, considering the non-uniformity of the confinement of the core UHPC by the square-section steel tube, a calculation model of the ultimate compressive capacity of UHPCFST specimens with square-section was proposed. Compared with the seven classical models, the calculation model proposed in this paper was more accurate.

Axial compressive behaviours of concrete-filled square GFRP tubular columns at low temperatures

This study reported experimental and theoretical investigations on low-temperature compression behaviours of concrete-filled square GFRP tubular (CFSFT) columns. The influences of low temperatures (T = 20, −30, −60, and −80 °C), thickness of GFRP tubular (tf = 3.66, 5.26, and 6.49 mm), and spacing of spiral GFRP bars (S = 40, 60, and 80 mm) on axial compressive behaviours of CFSFT columns were investigated through eighteen axial compression tests. Failure modes, load-axial strain behaviours, dilation behaviours of CFSFT columns, and load–strain behaviours of GFRP bars at low temperatures have been detailed reported. Test results indicated that reducing temperature from 20 to −80 °C decreased the confinement effectiveness of GFRP tubular on concrete core, but improved the compressive strength of GFRP tubular, concrete core and GFRP bars. These improved compressive strengths increased the ultimate compressive capacity of CFSFT columns. Prediction equations have been developed to estimate the ultimate compression capacity and its corresponding axial compression strain of CFSFT columns, which have considered the contribution of longitudinal GFRP bars and spiral GFRP bars. Validations of predictions against test results and comparisons with code predictions proved the improved accuracy of these developed prediction equations.

Ultimate compressive capacity of tapered concrete-filled double skin steel tubular stub columns with large hollow ratio

Recent developments in towers of wind turbine have heightened the need for tapered Concrete-Filled Double Skin Steel Tubular columns with Large Hollow Ratio (LHR-CFDST). It is necessary to further investigate the mechanical behaviour, key parameters' effects and design methods of tapered LHR-CFDST columns. This paper thus presents an analytical study on the tapered LHR-CFDST stub column under axial compression. A comprehensive finite element (FE) modelling is developed and then verified with the experimental data. A parametric study is conducted to reveal the effects of tapered angles, hollow ratios and diameter to thickness ratios of steel tubes. Further analysis is carried out to understand the compressive behaviour in terms of the full-range load-deformation relation, the axial compressive force distribution and the limitation of steel tube's diameter to thickness ratio. A simplified method for predicting the ultimate compressive capacity of tapered LHR-CFDST stub columns is proposed and the prediction agrees well with the test data.

Experimental investigation and design of sheathed LSF wall panels under eccentric axial compression

Sheathing is an important component in cold-formed Light gauge Steel Framed (LSF) walls and floors. LSF wall studs with one- or two-sided sheathing have been shown to have an increased ultimate compression capacity since the sheathing is capable of restraining global buckling modes. Although sheathing’s contribution has been ignored in the past, current design standards include provisions for the consideration of sheathing in the design of LSF walls. Australian cold-formed steel standard allows the designers to consider sheathing’s lateral and rotational restraints to studs, but it does not quantify the restraint values to be used. A recent report of American Iron and Steel Institute (AISI RP 13-1) provides suitable design guidelines for LSF walls with single sheathing, non-identical sheathing and different fastener spacings subject to axial compression, however, they have not been validated for LSF walls under combined compression and bending actions. An experimental investigation on LSF wall panels subject to combined actions due to eccentric loading was conducted in this research to understand the effects of loading eccentricity on sheathed LSF wall panels. Fifteen single stud wall panels of 1.5 m and 3.0 m height made of lipped channel studs were tested under concentric and major axis eccentric compression loading. Effects of sheathing and loading eccentricity on the failure modes and ultimate capacities were evaluated, and importantly, the suitability of the sheathing braced design guidelines in AISI RP 13-1 was investigated. The results showed that the use of the spring-based restraints recommended in AISI RP 13-1 with the linear interaction equation provides improvements in predicting the capacity of sheathed walls subject to eccentric compression.

Vertical field behavior of a deep large-diameter driven pipe pile in multilayered soils

Field testing was performed to examine vertical performances of a deep large-diameter driven pile used to support wind turbines in multilayered soils. The large-diameter pile was semiopen-ended and had an external diameter and length of 2.4 m and 113 m. The vertical load-displacement relationships were determined, and the shaft and base resistances were derived by analyzing segmented axial forces. The ultimate compressive capacity, determined using a modified Davisson's criterion, was 89.48 MN, which was nearly 20% and 100% larger than that estimated using the CABR JGG106-2014 (2014) criterion and dynamic load test data, respectively. The β values obtained using the modified Davisson's criterion were slightly larger than those obtained using the CABR JGG106-2014 (2014) criterion, and the MOT JTS167-2018 (2018) results were the most conservative. Although empirical methods incorporating parameters directly interpreted from standard penetration test results provided the most consistent estimates, they are limited to some geological conditions. Appropriate coefficients were suggested for empirical methods to calculate the base resistance. The shaft resistance contributed approximately 86% of the compressive axial force. In comparison, the ultimate tensile capacity was approximately 54.58 MN when using the CABR JGG106-2014 (2014) criterion, and the shaft resistance contributed approximately 93% of the tensile force.

Compression behaviours of concrete-filled Q690 high-strength steel tubular columns at low temperatures

Concrete-filled high-strength steel tubular columns (CFHSTCs) were developed using high-strength steel (HS) Q690 for cold-region engineering constructions. To study their compression behaviours at low temperatures, 15 CFHSTCs were tested under axial compression at different low temperatures within 20 ~ −90 °C. Including the influence of low temperatures, the effects of steel-tube wall thickness was also covered in this study. Compression test results showed that under the condition of low temperatures, local buckling of HS tube (HST), core crushing and weld fracture of HST occurred to the CFHSTCs. The CFHSTCs achieved the compression capacity as the crushing of concrete core, and HST local buckling at the recession working stage. Decreasing temperatures from 20 to −90 °C improved ultimate compression capacity and elastic stiffness of CFHSTCs. Moreover, enlarging the wall thickness of HST improved compression behaviours of CFHSTCs both at ambient and low temperatures. This paper also developed 3D finite element model (FEM) to simulate low-temperature compression behaviours of CFHSTCs. Validations of the FEM simulation results against 15 tests confirmed its capacity on simulating compression behaviours of CFHSTCs at both ambient and low temperatures.

Study on supporting time of tunnel lining in thin-layered rock mass

The thin-layered rock mass of Baokang tunnel has the characteristics of large deformation and failure of soft rock under the excavation unloading. More seriously, a serious question is that the lining cracking is prominent. The cause of the cracking can be traced to different failure modes of the surrounding rock mass. Specifically, the rock layer on left arch spandrel is prone to bending failure due to the action of tangential stress, while the right-side wall is prone to sliding failure due to the action of higher shear stress. Furthermore, the lining cracking may beyond the ultimate compressive capacity when the loosely collapsed rock mass acted on the lining. According to the transversely isotropic characteristics of layered rock mass, the failure approach index (FAI) was selected to evaluate the damage and failure of thin shale. Meanwhile, the result of the example shows that this index can effectively characterize the failure characteristics of the thin-layered rock mass. Hence, the FAI was used as an evaluation index of the loose failure of layered rock mass. In order to determine the lining support time, the stability of the lining under the action by the loose rock mass was analyzed by the numerical simulation. As a result, the distance between the lining and the face should not be bigger than 120m. According to the Feedback through onsite construction, the lining cracks didn’t appear under this supporting time, which ensured the stability of the lining structure. The research methods and ideas can provide reference for the similar tunnel lining construction in thin-layered rock mass.

A new composite column of FRP-steel-FRP clad tube filled with seawater sea-sand coral aggregate concrete: Concept and compressive behavior

A new composite column of FRP-steel-FRP clad tube (FSFCT) filled with seawater sea-sand coral aggregate concrete (SSCAC) was proposed. The FSFCT is composed of three layers: inner layer of glass fiber reinforced polymer (GFRP) tube, middle layer of carbon steel tube and outer layer of GFRP tube. This novel change allows the FSFCT not only to be filled with SSCAC instead of ordinary concrete but also to be widely used in harsh marine environment. A series of SSCAC filled FSFCT column specimens were prepared to investigate the compressive behavior of the new composite column considering the effects of different thicknesses of inner GFRP tube, middle carbon steel tube and outer GFRP tube. The test results showed that the load-strain curve of SSCAC filled FSFCT column under axial compression had obvious four section characteristics. Compared with steel tube thickness, the effects of outer GFRP tube thickness on the compressive behavior of SSCAC filled FSFCT column were more significant. The ultimate compressive capacity of SSCAC filled FSFCT column was increased by 66.5–131.9% in comparison with SSCAC filled carbon steel tube column with the same steel tube thickness. The confinement effect of outer GFRP tube was much better than that of inner GFRP tube.

The effect of longitudinal reinforcement ratio on the lateral buckling behavior of R/C walls modelled using prism elements

Studies on buildings subjected to earthquake action have shown that failure due to lateral buckling can cause structures to collapse. Therefore, transverse instability, its characteristics, and the mechanical factors that affect it need to be investigated to ensure the safety of structures. In the current experimental and analytical study, 22 tests were conducted using 11 column specimens constructed at a scale of 1:3 to simulate the boundary edges of structural walls. These specimens had varying ratios of longitudinal reinforcements (from 1.79% to 10.72%). The degree of tensile strain applied before compressive loading was 30‰ for all specimens. The present study examines the influence of the percentage of longitudinal reinforcement on the ultimate compressive capacity, deformation (axial and transverse), failure modes, and out-of-plane behavior of reinforced concrete seismic walls under earthquake loading conditions. It has been found that increasing the reinforcement ratio is not sufficient, by itself, to inhibit transverse instability, although it does affect its characteristics. It has also been discovered that rebar arrangement affects lateral buckling characteristics.