Summary The seismic performance of steel‐plate concrete (SC) shear walls is numerically investigated for various SC wall geometrical shapes. Steel faceplates and infill concrete are two main components of SC walls; a full connection between steel and concrete is required for composite action. A comprehensive set of SC wall specimens with different cross‐sectional shapes and geometrical properties were tested in the literature for evaluating their seismic behavior. The numerical responses of 17 tested SC walls, including rectangular, T‐shaped, and flanged walls, isolated and coupled walls, with and without boundary elements and endplates, subjected to cyclic lateral loading and a wide range of axial load ratio from 0.065 to 0.4, are evaluated using a finite element‐based software, LS‐DYNA. The predicted force‐displacement diagrams, failure modes, and damping ratios of the finite element models reasonably match the test observations. Also, three main analysis and design issues are evaluated, including the effect of coefficient of friction between concrete and steel faceplates, the effect of modeling pullout of shear studs from the concrete on the global response of SC walls, and the importance of the presence of shear studs and tie rods and the possible changes that may happen by changing the connector spacing to faceplate thickness ratio.

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This paper evaluates the applicability of several concrete models to simulate the behavior of concrete elements under monotonic and cyclic loadings. Several robust constitutive models based on the combination of plasticity and continuum damage or plasticity and smeared crack approach are selected. The behavior of one concrete element is evaluated under different uniaxial compression, uniaxial tension, biaxial compression, biaxial tension, biaxial compression-tension, and triaxial compression loads. Then, the applicability of the concrete models is investigated for two flexural beams under cyclic loading. Five concrete models available in the versatile finite element-based software LS-DYNA are selected, including Winfrith, CSCM, RHT, KCC, and CDPM. The prepeak, peak, and postpeak behaviors of all selected models are presented, including initial stiffness, peak strength, strain at peak strength, postpeak stiffness, and failure strain.concrete constitutive models, finite element analysis, LS-DYNA, monotonic and cyclic loading | INTRODUCTION AND BACKGROUNDMost finite element models identify the concrete with its elastoplastic behavior in compression and with a brittle elastic behavior in tension. A large variety of elasticity-and plasticity-based constitutive models have been proposed in recent years for the prediction of the uncracked concrete behavior, including empirical models, linear elastic, nonlinear elastic, plasticity-based models, models based on endochronic theory of inelasticity, fracturing models, and continuum damage mechanics models. [1] Various plasticity models have been developed for a better description of concrete compression strength under multidirectional stress states. The approach of plasticity models can be path-independent deformational theory or incremental theory, in which the total strain or total strain increment can be obtained by summation of elastic and plastic strain or strain increment, respectively. Assuming a linear elastic behavior for concrete can be quite accurate until it reaches to its peak tensile strength. [2] Under the compression loading, the behavior of concrete is highly nonlinear and inelastic. This model predicts the results with high error in cyclic loading. Under multiaxial compression loading, the use of nonlinear elastic models increases accuracy compared to linear elastic models. [3] These nonlinear elastic models can be categorized as secant formulations (hyperelastic models), which are path-independent and applicable to the monotonic or proportional loading, or tangential formulations (hypoelastic models), which better describe the concrete behavior under cyclic and nonproportional loading.For a better representation of concrete behavior in compression, different plasticity-based constitutive models have been developed over the last few decades. [4][5][6][7][8] All plasticity models are composed of three main components: yield criteria, flow rule, and hardening rule. The yield surface of concrete could be achieved by applying some corrections on the failure sur...

Steel-plate composite (SC) walls can be connected to a concrete basemat using a base plate and a set of anchors eccentric to the wall. The base plate can be separated into two parts so that the concrete of the wall and basemat is cohesive, and thus, the wall can be manufactured more easily and economically. Additionally, compression and shear demand are directly transferred from infill concrete to concrete basemat.Another change in the base plate connection of available tested walls involves transferring anchors to the bottom of faceplates. As a result of this modification, the base plate is removed from the force transmission chain, and the force is transferred directly from the wall to the anchors. After presenting the design criteria for this type of connection, three test walls with concrete foundations were verified in LS-Dyna.The walls were modeled with a split base plate connection and concentric anchors, and then compared to other types of wall-basemat connections. Three rectangular sections were then chosen as benchmarks and modeled with three anchors of different sizes to evaluate the effect of this parameter on walls behavior. The design equations presented for the single base plate connection were found applicable to design split base plate connections. Then all walls were compared to the test wall-fixed base wall connection. Finally, the models were analyzed with elastic walls to determine whether the foundation is stronger than the wall. The split base plate connection with concentric anchors was found to be stronger than connected parts and can be an alternative to existing connections.concentric anchors, concrete basemat, rectangular steel-plate composite walls, split base plate connection | INTRODUCTION AND BACKGROUNDSteel-plate composite (SC) walls are introduced as a lateral force resisting system in ASCE 7. [1] SC walls consist of two steel faceplates with concrete fill between the plates, with or without boundary elements. Tie bars or a combination of tie bars and shear studs can be used to achieve the composite action between the plates and concrete fill. An SC wall can be used when a relatively large seismic demand on the walls leads to dense reinforcement and large thicknesses in conventional concrete shear walls or relatively large wall thicknesses of the web infill and boundary elements in special plate shear walls. [2] SC walls correct the defects of steel plate shear walls. [3]

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