• Journal of Korean Association for Spatial Structures
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• v.10 no.4
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• pp.23-30
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• 2010

• Steel and Composite Structures
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• v.19 no.5
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• pp.1145-1165
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• 2015

A behavior model for screw connections is developed to provide a better representation of the nonlinear response of thin steel plate shear walls (TSPSWs) with infill plates attached to the boundary frame members via self-drilling screws. This analytical representation is based on the load-bearing deformation relationship between the infill plate and the screw threads. The model can be easily implemented in strip models of TSPSWs where the tension field action of the infill plates is represented by a series of parallel discrete tension-only strips. Previously reported experimental results from tests of two different TSPSWs are used to provide experimental validation of the modeling approach. The beam-to-column connection behavior was also included in the analyses using a four parameter rotational spring model that was calibrated to a test of an identical frame as used for the TSPSW specimens but without the infill plates. The complete TSPSW models consisting of strips representing the infill plates, zero length elements representing the load-bearing deformation response of the screw connection at each end of the strips and the four parameter spring model at each beam-to-column connection are shown to have good agreement with the experimental results. The resulting models should enable design and analysis of TSPSWs for both new construction and retrofit of existing buildings.

• Journal of the Earthquake Engineering Society of Korea
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• v.18 no.2
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• pp.79-87
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• 2014

Masonry-infilled walls have been used in reinforced concrete(RC) frame structures as interior and exterior partition walls. Since these walls are considered as nonstructural elements, they were only considered as additional mass. However, infill walls tend to interact with the structure's overall strength, rigidity, and energy dissipation. Infill walls have been analyzed by finite element method or transposed as equivalent strut model. The equivalent strut model is a typical method to evaluate masonry-infilled structure to avoid the burden of complex finite element model. This study compares different strut models to identify their properties and applicability with regard to the characteristics of the structure and various material models.

• Earthquakes and Structures
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• v.10 no.1
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• pp.1-23
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• 2016

Steel plate shear walls (SPSWs) have been shown to be efficient lateral force-resisting systems, which are increasingly used in new and retrofit construction. These structural systems are designed with either stiffened and stocky or unstiffened and slender web plates based on disparate structural and economical considerations. Based on some limited reported studies, on the other hand, employment of low yield point (LYP) steel infill plates with extremely low yield strength, and high ductility as well as elongation properties is found to facilitate the design and improve the structural behavior and seismic performance of the SPSW systems. On this basis, this paper reports system-level investigations on the seismic response assessment of multi-story SPSW frames under the action of earthquake ground motions. The effectiveness of the strip model in representing the behaviors of SPSWs with different buckling and yielding properties is primarily verified. Subsequently, the structural and seismic performances of several code-designed and retrofitted SPSW frames with conventional and LYP steel infill plates are investigated through detailed modal and nonlinear time-history analyses. Evaluation of various seismic response parameters including drift, acceleration, base shear and moment, column axial load, and web-plate ductility demands, demonstrates the capabilities of SPSW systems in improving the seismic performance of structures and reveals various advantages of use of LYP steel material in seismic design and retrofit of SPSW systems, in particular, application of LYP steel infill plates of double thickness in seismic retrofit of conventional steel and code-designed SPSW frames.

• Earthquakes and Structures
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• v.10 no.3
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• pp.539-562
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• 2016

The seismic behavior of a ${\frac{1}{2}}$ scaled, three-story three-bay RC frame with masonry infill walls was studied experimentally and numerically. Pseudo-dynamic test results showed that despite following the column design provisions of modern seismic codes and neglecting the presence of infill walls, shear induced damage is unavoidable in the boundary columns. A finite element model was validated by using the results of available one-story one-bay frame tests in the literature. Simulations of the examined test frame demonstrated that boundary columns are subjected to shear demands in excess of their shear capacity. Seismic assessment of the test frame was conducted by using ASCE/SEI 41-06 (2006) guidelines and the obtained results were compared with the damage observed during experiment. ASCE/SEI 41-06 method for the assessment of boundary columns was found unsatisfactory in estimating the observed damage. Damage estimations were improved when the strain limits were used within the plastic hinge zone instead of column full height.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.53-56
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• 2008

A reinforced concrete (RC) cast-in-place (CIP) infill wall retrofitting method may provide an improved seismic performance and economical efficiency for the non-ductile rahmen structures. In this study, four one story-one bay non-ductile frame were constructed and retrofitted with CIP infill wall to evaluate seismic performance of CIP infill wall-frame. From the test results, infill wall-frame exhibited a marked increase in shear strength compared to non-ductile RC frame specimen. But the ductility and story-drift at maximum load were decreased when shear strength of infill wall larger than that of existing RC frame. Therefore, it is confirmed that adequate reinforcement detail is required to assure sufficient seismic performance.

• Journal of the Korean Institute of Rural Architecture
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• v.16 no.2
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• pp.1-8
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• 2014

In the past, Korea was classified as a region not affected by earthquakes. However, recent increase of earthquakes has forced to strengthen standards of earthquake resistant designs of structures to minimize seismic damage. In addition, it was thought that masonry infill walls in buildings are only acting as partitions, so these walls are not considered in analyzing building structures. But it was found that when seismic loads are applied to a structure with masonry infill walls, the walls affect the structure. Accordingly, this study conducted nonlinear static analyses for a structure constructed before applying earthquake resistant designs in two cases: when considering masonry walls and when not. The result showed that the seismic performance of the structure is insufficient. Thus, the structural resistance of the structure was also studied in two cases: when reinforcing with steel plate braces and when using carbon fiber braces. In the two cases reinforcing two different stiffeners, it was appeared that the behaviors of the structure were similar, though the cross-section area of a carbon fiber brace used to reinforcing the structure is only 12.6% of a steel plate brace, and its weight is only 2.8%. Thus, the reinforcing effect of the thin, light-weighted carbon fiber brace is much larger than that of the steel plate brace, when considering usability and constructability of both materials.

• Steel and Composite Structures
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• v.31 no.1
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• pp.85-98
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• 2019

Nonlinear seismic performances of code designed Perforated Steel Plate Shear Walls (P-SPSW) were studied. Three multi-storey (4-, 8-, and 12-storey) P-SPSWs were designed according to Canadian seismic provisions and their performance was evaluated using time history analysis for ground motions compatible with Vancouver response spectrum. The selected code designed P-SPSWs exhibited excellent seismic performance with high ductility and strength. The current code equation was found to provide a good estimation of the shear strength of the perforated infill plate, especially when the infill plate is yielded. The applicability of the strip model, originally proposed for solid infill plate, was also evaluated for P-SPSW and two different strip models were studied. It was observed that the strip model with strip widths equal to center to center diagonal distance between each perforation line could reasonably predict the inelastic behavior of unstiffened P-SPSWs. The strip model slightly underestimated the initial stiffness; however, the ultimate strength was predicted well. Furthermore, applicability of simple shear-flexure beam model for determination of fundamental periods of P-SPSWs was studied.

• Structural Engineering and Mechanics
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• v.44 no.1
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• pp.73-84
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• 2012

This paper strongly addresses to the problem of the mechanical systems in which parameters are uncertain and bounded. Interval calculation is used to find sharp bounds of the structural parameters for infilled frame system modeled with finite element method. Infill walls are generally treated as non-structural elements considerably to improve the lateral stiffness, strength and ductility of the structure together with the frame elements. Because of their complex nature, they are often neglected in the analytical model of building structures. However, in seismic design, ignoring the effect of infill wall in a numerical model does not accurately simulate the physical behavior. In this context, there are still some uncertainties in mechanical and also geometrical properties in the analysis and design procedure of infill walls. Structural uncertainties can be studied with a finite element formulation to determine sharp bounds of the structural parameters such as wall thickness and Young's modulus. In order to accomplish this sharp solution as much as possible, interval finite element approach can be considered, too. The structural parameters can be considered as interval variables by using the interval number, thus the structural stiffness matrix may be divided into the product of two parts which correspond to the interval values and the deterministic value.

• Journal of the Korea Concrete Institute
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• v.21 no.3
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• pp.327-335
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• 2009

In the seismic region, non-ductile structures often form soft story and exhibit brittle collapse. However, structure demolition and new structure construction strategies have serious problems, as construction waste, environmental pollution and popular complain. And these methods can be uneconomical. Therefore, to satisfy seismic performance, so many seismic retrofit methods have been investigated. There are some retrofit methods as infill walls, steel brace, continuous walls, buttress, wing walls, jacketing of column or beam. Among them, the infilled frames exhibit complex behavior as follows: flexible frames experiment large deflection and rotations at the joints, and infilled shear walls fail mainly in shear at relatively small displacements. Therefore, the combined action of the composite system differs significantly from that of the frame or wall alone. Purpose of research is evaluation on the seismic performance of infill walls, and improvement concept of this paper is use of SHCCs (strain-hardening cementitious composites) to absorb damage energy effectively. The experimental investigation consisted of cyclic loading tests on 1/3-scale models of infill walls. The experimental results, as expected, show that the multiple crack pattern, strength, and energy dissipation capacity are superior for SHCC infill wall due to bridging of fibers and stress redistribution in cement matrix.