• Structural Engineering and Mechanics
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• v.86 no.1
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• pp.49-68
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• 2023

This study investigates the static and dynamic structural analysis of symmetrical and asymmetrical coupled shear walls using the continuous and modified transfer matrix methods by idealizing the coupled shear wall as a three-field CTB-type replacement beam. The coupled shear wall is modeled as a continuous structure consisting of the parallel coupling of a Timoshenko beam in tension (with axial extensibility in the shear walls) and a shear beam (replacing the beam coupling effect between the shear walls). The variational method using the Hamilton principle is used to obtain the coupled differential equations and the boundary conditions associated with the model. Using the continuous method, closed-form analytical solutions to the differential equation for the coupled shear wall with uniform properties along the height are derived and a numerical solution using the modified transfer matrix is proposed to overcome the difficulty of coupled shear walls with non-uniform properties along height. The computational advantage of the modified transfer matrix method compared to the classical method is shown. The results of the numerical examples and the parametric analysis show that the proposed analytical and numerical model and method is accurate, reliable and involves reduced processing time for generalized static and dynamic structural analysis of coupled shear walls at a preliminary stage and can used as a verification method in the final stage of the project.

• Steel and Composite Structures
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• v.3 no.6
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• pp.403-420
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• 2003

In the paper one investigates the benefits deriving from the introduction of SMA provisions in a structure subject to dynamic excitation and vertical loads. At this purpose one considers a multi-degree-of-freedom (mdof) shear elastic-plastic frame and designs couples of super-elastic SMA tendons to be placed at critical locations of the structure. Particular attention is focused on the reduction of $P-{\Delta}$ effects.

• 한국전산유체공학회:학술대회논문집
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• 2003.08a
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• pp.139-143
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• 2003

In this study the numerical analyses on cavity flow in supersonic flow field are conducted. According to the length-to-depth ratio of cavity, the shear layer is changed, consequently influencing on vortex structure inside the cavity. Especially in case the fluid flow outside cavity impinges inside the cavity, the oscillation of the cavity flow is identified. Another result is that though the cavity flow shows the unsteadiness, characteristics of cavity flow can be represented by pressure coefficients converged.

• Structural Engineering and Mechanics
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• v.40 no.6
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• pp.763-782
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• 2011

Results from nonlinear time-history analyses of wall-frame structural models indicate that the condition of vulnerable foundations -for which uplifting and reaching the bearing capacity of the supporting soil can occur before yielding at the base of the shear walls- may not be necessarily detrimental to the drift response of buildings under strong ground motions. Analyses also show that a soil-foundation system can inherently have deformation capacity well in excess of the demand and thus act as a source of energy dissipation that protects the structural integrity of the shear walls.

• Earthquakes and Structures
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• v.18 no.6
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• pp.667-675
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• 2020

The current study compares the effect of structure-soil-structure interaction (SSSI) on the dynamic responses of adjacent buildings and isolated structures including soil-structure interaction (SSI) with the responses of fixed-base structures. Structural responses such as the relative acceleration, displacement, drift and shear force were considered under earthquake ground motion excitation. For this purpose, 5-, 10- and 15-story structures with 2-bay moment resisting frames resting on shallow foundations were modeled as a group of buildings in soft soil media. Viscous lateral boundaries and interface elements were applied to the soil model to simulate semi-infinite soil media, frictional contact and probable slip under seismic excitation. The direct method was employed for fully nonlinear time-history dynamic analysis in OpenSees using 3D finite element soil-structure models with different building positions. The results showed that the responses of the grouped structures were strongly influenced by the adjacent structures. The responses were as much as 4 times greater for drift and 2.3 times greater for shear force than the responses of fixed-base models.

• Steel and Composite Structures
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• v.11 no.5
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• pp.375-390
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• 2011

Composite beam, which combined the material characteristic of the steel and concrete, has been widely used in the construction of various building and bridge system. For the effective application of the composite beam, the composite action on the composite interface between the concrete element and the steel element should be achieved by shear connectors. The behavioral characteristics of composite beam are related with the degree of interaction and the degree of shear connection according to the shear strength and shear stiffness of the stud shear connectors. These two concepts are also affected by the number of installed shear connector and the strength of composite materials. In this study, experimental and analytical evaluations of the degree of shear connection affected by stud diameter were conducted, and the relationship between structural behavior and the degree of shear connection was verified. The very small difference among the ultimate loads of the specimens depending on the change of the degree of connection was possibly because of the dependence of the ultimate load on the characteristic of plastic moment of the composite beam.

• Smart Structures and Systems
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• v.24 no.3
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• pp.345-360
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• 2019

The shear keys are set in a seismic isolation system to resist the long-term service loadings, and are cut off to isolate the earthquakes. This paper investigated the influence of shear keys on the seismic performance of a vertical spring-viscous damper-concave Coulomb friction isolation system by an incremental dynamic analysis (IDA) and a performance-based assessment. Results show that the cutting off process of shear keys should be simulated in a numerical analysis to accurately predict the seismic responses of isolation system. Ignoring the cutting off process of shear keys usually leads to untrue seismic responses in a numerical analysis, and many of them are unsafe for the design of isolated structure. And those errors will be increased by increasing the cutting off force of shear keys and decreasing the spring constant of shear keys, especially under a feeble earthquake. The viscous damping action postpones the cutting off time of shear keys during earthquakes, and reduces the seismic isolation efficiency. However, this point can be improved by increasing the spring constant of shear keys.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.9
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• pp.191-198
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• 2019

All over the Republic of Korea, there are many masonry buildings which have been built since 1970s. When the earthquake at Po-Hang occurred, this is the main cause of huge damage because the masonry buildings have not seismic capacity. When masonry buildings are failed, two type of the failure modes can be shown, which are in-plane mode and out-plane mode. In-plane mode can have seismic capacity in masonry so diagonal shear test is performed in this study. The purpose of this study was to find the best way to reinforce the materials through the diagonal shear test. Through the test, shear stress and shear modulus of elasticity will be calculated, referred to the ASTM E 519-02. The variables in this test are ${\phi}3$ wire, three types of wire meshes, polypropylene strap and different types of brick. Each variable is applied to the same condition of the $1.2m{\times}1.2m$ masonry walls which are made by ASTM E 519-02. Compared to each variable with shear stress and shear modulus of elasticity, the best way of reinforcing method to have seismic capacity will be proved in this study.

• Structural Engineering and Mechanics
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• v.77 no.6
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• pp.721-734
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• 2021

The seismic analysis of structures without applying the effects of soil can undermine functional objectives of structure so that it can affect all the desired purposes at the design and control stages of the structure. In this research, employing OpenSees and MATLAB software simultaneously and developing a definite three-dimensional finite element model of a high-rise concrete structure, designed using performance-based plastic design approach, the performance of Tuned Mass Damper (TMD) and Active Mass Damper (AMD) is both examined and compared. Moreover some less noted aspects such as nonlinear interaction of soil and structure, uplift, nonlinear behavior of structure and structural torsion have received more attention. For this purpose, the analysis of time history on the structural model has been performed under 22 far-field accelerogram records. Examining a full range of all structural seismic responses, including lateral displacement, acceleration, inter-story drift, lost plastic energy, number of plastic hinges, story shear force and uplift. The results indicate that TMD performs better than AMD except for lateral displacement and inter-story drift to control other structural responses. Because on the one hand, nonlinear structural parameters and soil-structure interaction have been added and on the other hand, the restriction on the control force applied that leads up to saturation phenomenon in the active control system affect the performance of AMD. Moreover, the control force applied by structural control system has created undesirable acceleration and shear force in the structure.

• Journal of the Korean Geotechnical Society
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• v.24 no.1
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• pp.51-59
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• 2008

In this study, cyclic shear characterics of sand-clay mixtures were analyzed. In order to perform cyclic triaxial tests on sand clay mixtures, natural clays with activity and silica sand were mixed variously to reproduce soils with wide range of grain size compositions. Test specimens with various fines contents were prepared by the moisture compaction and pre-consolidation methods, while paying attention to the void ratio expressed in terms of the sand structure and clay structures, and undrained cyclic shear tests were performed. In the test results, cyclic shear strength decreased with increasing of sand granular void ratio below 20% of fine contents. When the granular void ratio of the test specimen exceeded the maximum void ratio of the silica sand, the clay matrix dominated the soil structure, and soil structures were not influenced by compaction energy. It was observed that, the matrix structure of the coarse particles has great effect on the undrained cyclic shear strength characteristics for sand-clay mixtures, and therefore, it is more appropriate to pay more attention to the density of the sand structure, rather than to the fines content.