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This 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. [ABSTRACT FROM AUTHOR]

This paper investigates the seismic behavior of a glass curtain wall system under various loading scenarios. Experimental set‐ups and approaches were developed to test full‐scale fully tempered (FT) insulating glass curtain wall systems subjected to three loading protocols: quasi‐static in‐plane loading, dynamic in‐plane loading, and dynamic coupled in‐plane and out‐of‐plane loading. A refined finite element (FE) model was developed to understand the behavior of the system. The average drift associated with glass cracking and fallout was found to be nearly identical for quasi‐static and dynamic in‐plane loading, indicating that in‐plane floor accelerations exerted marginal influence on the failure of the glass curtain walls. Bi‐directional loading led to an approximately 30% decrease in the glass fallout drift compared with in‐plane loading. This is because the out‐of‐plane drift placed an increased stress demand on the glass panel, as indicated by the FE analysis. Both the experimental tests and FE analysis revealed that the ASCE 7–16 formula, which is used to calculate the drift of contact between the glass and frame, is nonconservative as it does not consider the deformation of the surrounding frame and the friction between the gasket and the glass. The failure mechanism of the glass panel was caused by the stress concentrations at the diagonal corners due to glass‐to‐frame contact. The FE analysis indicated that the interactional effect among different glass units was negligible, and the glass panels exhibited a similar stress state regardless of their positions. [ABSTRACT FROM AUTHOR]

The steel reinforced concrete (SRC) wall consists of structural steel embedded at the boundary elements of a reinforced concrete (RC) wall. The use of SRC walls has gained popularity in the construction of high-rise buildings because of their superior performance over conventional RC walls. This paper presents a series of quasi-static tests used to examine the behavior of SRC walls subjected to high axial force and lateral cyclic loading. The SRC wall specimens showed increased flexural strength and deformation capacity relative to their RC wall counterpart. The flexural strength of SRC walls was found to increase with increasing area ratio of embedded structural steel, while the section type of embedded steel did not affect the wall's strength. The SRC walls under high axial force ratio had an ultimate lateral drift ratio of approximately 1.4%. In addition, a multi-layer shell element model was developed for the SRC walls and was implemented in the OpenSees program. The numerical model was validated through comparison with the test data. The model was able to predict the lateral stiffness, strength and deformation capacities of SRC walls with a reasonable level of accuracy. Finally, a number of issues for the design of SRC walls are discussed, along with a collection and analysis of the test data, including (1) evaluation of flexural strength, (2) calculation of effective flexural stiffness, and (3) inelastic deformation capacity of SRC walls. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, seismic behavior of the shear link "fuse" used in the steel coupling beam was examined through quasi-static tests on twelve link specimens. The test variables included the steel type for web, link length ratio, stiffener configuration, and loading protocol. All link specimens yielded in shear, followed by two types of failure modes, i. e., link web fracture and fracture at the weld connecting link flange to end plate. The overstrength factors of the link specimens reached approximately 1.86, higher than a value of 1.5 recommended by Popov et al. The specimens had an inelastic rotation of approximately 0. 15 rad, much larger than 0. 08 rad required by the AISC 341-10 provisions. Using the low yield steel LY225 instead of Q235 steel for web increased the inelastic rotation of the links by 23% and the cumulative plastic rotation by 52%. Setting stiffeners on one side of the web only or on both sides of webs made very limited difference on the behavior of the links. Increase of the stiffener spacing led to early-stage web buckling and obvious strength degradation. The low-yield steel links are thus recommended to follow the requirements of stiffener details specified by AISC 341-10 and GB 50011-2010. The axial displacement that occurred during the specimens were subjected to cyclic shears included the geometrical displacement and inelastic axial deformation induced by shears. The inelastic axial deformation was found to be proportional to the cumulative plastic rotation of the links. [ABSTRACT FROM AUTHOR]

SUMMARY The steel tube-reinforced concrete (ST-RC) composite column is a novel type of composite column, which consists of a steel tube embedded in RC. In this paper, the seismic behavior of ST-RC columns is examined through a series of experiments in which 10 one-third scale column specimens were subjected to axial forces and lateral cyclic loading. The test variables include the axial force ratio applied to the columns and the amount of transverse reinforcement. All specimens failed in a flexural mode, showing stable hysteresis loops. Thanks to the steel tube and the high-strength concrete it is filled with, the ST-RC column specimens had approximately 30% lower axial force ratios and 22% higher maximum bending moments relative to the comparable RC columns when subjected to identical axial compressive loads. The amount of transverse reinforcement made only a small difference to the lateral load-carrying capacity but significantly affected the deformation and energy dissipation capacity of the ST-RC columns. The specimens that satisfied the requirements for transverse reinforcement adopted for medium ductile RC columns as specified by the Chinese Code for Seismic Design of Buildings (GB 50011-2010) and EuroCode 8 achieved an ultimate drift ratio of around 0.03 and a displacement ductility ratio of approximately 5. The design formulas used to evaluate the strength capacity of the ST-RC columns were developed on the basis of the superposition method. The predictions from the formulas showed good agreement with the test results, with errors no greater than 10%. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: This paper proposes an innovative structural wall, named “the steel tube–double steel plate–concrete composite wall”, which is suited for use in high-rise buildings. The composite wall consists of concrete filled steel tubular (CFST) boundary elements and a double “skin” composite wall web where two steel plates are connected by tie bolts with space between them filled with concrete. The seismic behavior of the composite walls was examined through a series of experiments in which five slender rectangular wall specimens were subjected to axial forces and lateral cyclic loading. The specimens failed in a flexural mode, characterized by local buckling of the steel tubes and plates, fracture of the steel tubes, and concrete crushing at the wall base. The extent of the CFST boundary element was found to significantly affect the deformation and energy dissipation capacities of the walls. The area ratio of steel plates had a minimal effect on the deformation capacity of the slender walls. The addition of circular steel tubes embedded in the CFST boundary elements obviously increased the lateral load-carrying capacity of the walls. When the CFST boundary element's extent was 0.2 times the wall's sectional depth and the test axial force ratio was no more than 0.25, the walls had a yield drift ratio of over 0.005 and an ultimate drift ratio of around 0.03. Simplified formulas used to evaluate the flexure strength of the composite walls were proposed. The evaluated results had good agreement with the test results, with errors no greater than 10%. [Copyright &y& Elsevier]

This paper proposed an innovative composite wall, named the steel tube-double plate-concrete composite shear wall, which is suited for use in the lower stories of super high-rise buildings. The seismic behavior of the composite walls was examined through results of an experimental research program where five rectangle-shaped wall specimens with a shear span ratio of 2.5 were tested. The test results indicate that the specimens fail in a flexural mode, characterized by local buckling of boundary steel tubes and steel plates, fracture of steel tubes, and compressive crushing of concrete at the wall base. The extent of concrete filled steel tubular (CFST) boundary elements significantly affects the deformation and energy dissipation capacities of the composite walls. The area ratio of steel plate has a minimal effect on the deformation capacity of the wall specimens. The addition of circular steel tubes embedded in the CFST boundary elements leads to an increase in the lateral load-carrying capacity of the composite walls, but it does not increase the wall's deformation capacity. When the CFST boundary element's extent is 0. 2 times the wall's sectional depth and the designed axial force ratio is 0.45, the wall specimen has a yield drift ratio of over 0. 005 rad and an ultimate drift ratio of 0. 030 rad. In addition, simplified formulas used to calculate the flexure strength of the composite walls were proposed. The evaluated results show good agreement with the test results, with errors no more than 10%. [ABSTRACT FROM AUTHOR]

• Full-scale tests were conducted on steel coupling beam-to-SRC wall joints. • The steel coupling beam-to-SRC wall joints failed in panel shear mode. • The capacity designed joint had slight damage upon to failure of steel beam. • Design model for calculating the nominal joint strength is presented. • Mechanism and accuracy of design model are validated by test data and FE analysis. A hybrid coupled wall system, where steel coupling beams couple steel reinforced concrete (SRC) walls in series, has been recognized as an alternative to reinforced concrete (RC) coupled wall systems for enhanced seismic performance of high-rise buildings. A key issue of this system is seismic design of steel coupling beam-to-SRC wall joints. This paper presents a series of full-scale tests to investigate the cyclic behavior and strength capacity of the steel coupling beam-to-SRC wall joints, where a steel beam was rigidly connected to an encased steel column in wall boundary using a fully welded connection detail. The steel beam-to-SRC wall joints failed in panel shear mode, characterized by yielding of the steel web panel and joint transverse reinforcement, and crisscrossed-diagonal cracking and crushing of joint panel concrete. A design model for calculating the nominal strength of the steel beam-to-SRC wall joint is presented. The accuracy of the design model was verified against the collected test data and additional finite element (FE) analysis. The experimental tests and FE analysis also identified that severe vertical cracks might develop along the inner side of wall boundary element, due to horizontally tensile forces induced by the steel beam flange. Increased amount of horizontally distributed rebar is recommended to be assigned in around the join region, in order to control such unwanted damage. In addition, the test results of one specimen demonstrated that properly designed beam-to-wall joint remained slightly damaged when the steel coupling beam fully developed its plastic rotation. [ABSTRACT FROM AUTHOR]

To study the seismic behavior of composite-sectioned high strength concrete filled steel tubular (CSCFT) columns, quasi-static tests on six specimens were conducted. The test variables included the axial force ratio, wall thickness and width-to-thickness ratio of square steel tube, confinement index of circular concrete filled steel tube (CFT). Test results indicate that the failure mode of the CSCKF column specimens is characterized by wall buckling of square steel tube and crushing of partial concrete between the square steel tube and the circular steel tube within a height of 300mm from the column base. The lateral force-displacement hysteretic loops are plump. At the peak lateral force, the drift ratio of one specimen is a little bit less than 1/100 since it has a design value of axial force ratio close to 1.0, and the drift ratios of other 5 specimens are larger than 1/100. As the wall width-to-thickness ratio of square steel tube reduced, or the confinement index of CFT increased, the initial secant stiffness and the ultimate drift ratio are increased. As the wall thickness of square steel tube increased, the bending strength of specimen under axial compressive force is enhanced. The bending strength of the specimens calculated by the superposition method and by the plane section assumption has good agreement with the test results. [ABSTRACT FROM AUTHOR]

Abstract: This paper proposes an innovative composite shear wall, named the steel tube-reinforced concrete (ST-RC) composite wall, with steel tubes embedded at the wall boundary elements and fully anchored within the foundation. This arrangement is supposed to enhance the wall’s seismic performance. A series of quasi-static tests were performed to examine the behavior of the ST-RC walls when subjected to high axial forces and lateral cyclic loads. The area ratios of steel tube and of concrete filled steel tube (CFST) (i.e. the ratios of the cross-sectional areas of steel tubes and of CFSTs over that of the wall boundary element, respectively), axial force ratio, and cross-sectional shape of walls were taken as major test variables. All specimens failed in a flexural mode, characterized by tensile yield of the vertical rebars and steel tubes in the boundary elements and compressive crushing of concrete at the wall bottom. The test results showed that the ST-RC composite walls had larger load-carrying and deformation capacities relative to the RC wall counterpart. The deformation capacity of the rectangular-shaped composite walls increased with an increase in the area ratios of steel tube and of CFST and decreased with an increase in the applied axial force ratio. The barbell-shaped composite wall that was configured with edge columns had much larger deformation and energy dissipation capacities than the rectangular-shaped composite walls. In addition, simplified formulation was proposed to evaluate the lateral load-carrying capacity of the ST-RC composite walls. The evaluated results showed good agreement with the test results, with errors no more than 10%. [Copyright &y& Elsevier]