• Structural Engineering and Mechanics
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• v.14 no.3
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• pp.365-380
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• 2002

Following a series of experiments on isolated low-rise RC shear walls with openings, a theoretical study on the backbone curve of a perforated shear wall shows that there are some important observations from experimental results that make clear a semi-empirical formula of the backbone curve of a perforated wall. Critical shear zones can be depicted from the configuration of shear walls with openings. Different factors, including the size and location of shear wall openings, the wall's height/width ratio, horizontal and vertical steel bar ratios, and location and amount of diagonal steel bars are involved in the derivation of the backbone curve. Bending and shear effects are also considered in the paper. In addition, a comparison of load and displacement for solid and perforated shear walls is discussed. Generally, the comparison between experimental curves and computed backbone curves is favorable.

• Structural Engineering and Mechanics
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• v.83 no.6
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• pp.799-810
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• 2022

This study investigated the effect of the strengthening efficiency of unbonded steel-bar truss system on the out-of-plane behavior of perforated masonry walls. Four full-scale unreinforced masonry (URM) walls with two different planes were prepared using the unbonded steel-bar truss system and a URM walls without strengthening. All masonry walls were tested under constant axial and cyclic lateral loads. The obtained test results indicated that the pinching effect in the out-plane behavior of masonry walls tends to decrease in the in- and out-of-plane strengthened URM walls using the unbonded steel-bar truss system with the higher prestressing force ratio (R_p) of vertical reinforcing bars in the unbonded steel-bar truss system, regardless of the perforated type of the masonry wall. Consequently, the highest maximum shear resistance and cumulative dissipated energy at peak load in the post-peak behavior were observed in the in- and out-plane strengthened URM walls with the highest R_p values, which are 2.7 and 6.0 times higher than those of URM. In particular, the strengthening efficiency of the unbonded steel-bar truss system was primarily attributed to the vertical prestressed steel-bars rather than the diagonal steel-bars, which indicates that the strains in the vertical prestressed steel-bars at the peak load were approximately 1.6 times higher than those in the diagonal steel-bars.

• Earthquakes and Structures
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• v.6 no.2
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• pp.181-199
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• 2014

The infill walls, whose contribution to the earthquake resistance of a structure is generally ignored due to their limited lateral rigidities, constitute a part of the lateral load bearing system of an RC frame structure. A common method for improving the earthquake behavior of RC frame structures is increasing the contribution of the infill walls to the overall lateral rigidity by strengthening them through different techniques. The present study investigates the influence of externally bonded perforated steel plates on the load capacities, rigidities, and ductilities of hollow brick infill walls. For this purpose, a reference (unstrengthened) and twelve strengthened specimens were subjected to monotonic diagonal compression. The experiments indicated that the spacing of the bolts, connecting the plates to the wall, have a more profound effect on the behavior of a brick wall compared to the thickness of the strengthening plates. Furthermore, an increase in the plate thickness was shown to result in a considerable improvement in the behavior of the wall only if the plates are connected to the wall with closely-spaced bolts. This strengthening technique was found to increase the energy absorption capacities of the walls between 4 and 14 times the capacity of the reference wall. The strengthened walls reached ultimate loads 30-160% greater than the reference wall and all strengthened walls remained intact till the end of the test.

• 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.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.1
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• pp.119-128
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• 2015

This study investigates the wave pressure characteristics of the pile-supported breakwater with single or double perforated walls through 2-D hydraulic experiments and the measured wave pressures are compared to those of wave pressures by Goda's formula. For single chamber, the measured wave pressures in the front wall and rear wall decreased to about 25% and 30%, respectively, compared to those of wave pressures by Goda's formula. Also, the decrease in the wave pressures for double chamber were about 27%, 53%, and 64% in the front wall, middle wall, and rear wall, respectively. It was found that the pile-supported breakwater with double perforated walls was more efficient than the single chamber due to wave dissipation effects of double slit walls with horizontal slits.

• Steel and Composite Structures
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• v.18 no.4
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• pp.811-831
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• 2015

This paper focuses on the strengthening methods used for improving the compression behaviors of perforated box-section walls as provided in the anchorage zones of steel pylons. Rectangular plates containing double-row continuous elliptical holes are investigated by employing the boundary condition of simple supporting on four edges in the out-of-plane direction of plate. Two types of strengthening stiffeners, named flat stiffener (FS) and longitudinal stiffener (LS), are considered. Uniaxial compression tests are first conducted for 18 specimens, of which 5 are unstrengthened plates and 13 are strengthened plates. The mechanical behaviors such as stress concentration, out-of-plane deformation, failure pattern, and elasto-plastic ultimate strength are experimentally investigated. Finite element (FE) models are also developed to predict the ultimate strengths of plates with various dimensions. The results of FE analysis are validated by test data. The influences of non-dimensional parameters including plate aspect ratio, hole spacing, hole width, stiffener slenderness ratio, as well as stiffener thickness on the ultimate strengths are illustrated on the basis of numerous parametric studies. Comparison of strengthening efficiency shows that the continuous longitudinal stiffener is the best strengthening method for such perforated plates. The simplified formulas used for estimating the compression strengths of strengthened plates are finally proposed.

• Earthquakes and Structures
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• v.20 no.4
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• pp.377-388
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• 2021

Thin perforated Steel Plate Shear Walls (SPSWs) are among the most common types of seismic energy dissipation systems to protect the main boundary components of SPSWs from fatal fractures in the high-risk zones. In this paper, the cyclic behavior of the different circular hole patterns under cyclic loading is reported. Based on the experimental results, it can be concluded that a change in the perforation pattern of the circular holes leads to a change in the locations of the fracture tendency over the web plate, especially at the plate-frame interactions. Accordingly, the cyclic responses of the tested specimens were simulated by finite element method using the ABAQUS package. Likewise, perforated shear panels with a new perforation pattern obtained by implementing Topology Optimization (TO) were proposed. It was found that the ultimate shear strength of the specimen with the proposed TO perforation pattern was higher than that of the other specimens. In addition, theoretical equations using the Plate-Frame Interaction (PFI) method were used to predict the shear strength and initial stiffness of the considered specimens. The theoretical results showed that the proposed reduced coefficients relationships cannot accurately predict the shear strength and initial stiffness of the considered perforated shear panels. Therefore, the reduced coefficients should be adopted in the theoretical equations based on the obtained experimental and numerical results. Finally, with the results of this study, the shear strength and initial stiffness of these types of perforated shear panels can be predicted by PFI method.

• Structural Engineering and Mechanics
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• v.74 no.3
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• pp.325-339
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• 2020

This study presents a practical application of topology optimization (TO) technique to seek the best form of perforated steel plate shear walls (PSPSW) in simple frames. For the numerical investigation, a finite element model is proposed based on the recent particular form of PSPSW that is called the ring-shaped steel plate shear wall. The TO is applied based on the sensitivity analysis to maximize the reaction forces as the objective function considering the fracture tendency. For this purpose, TO is conducted under a monotonic and cyclic loading considering the nonlinear behavior (material and geometry) and buckling. Also, the effect of plate thickness is studied on the TO results. The final material volume of the optimized plate is limited to the material volume of the ring-shaped plate. Finally, an optimized plate is introduced and its nonlinear behavior is investigated under a cyclic and monotonic loading. For a more comprehensive view, the results are compared to the ring-shaped and four usual forms of SPSWs. The material volume of the plate for all the models is the same. The results indicate the strength, load-carrying, and energy dissipation in the optimized plate are increased while the fracture tendency is reduced without changing the material volume.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.10a
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• pp.149-150
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• 2013

Recently, various types of perforated breakwaters are being constructed for protecting offshore storm waves. In general, perforated breakwaters have wave chambers with perforated walls at seaside. Purposes of the wave chambers are to reduce wave reflections and maximum wave forces acting on the breakwater. Impact wave forces due to wave breaking can attack to the perforated wall directly, so the effects have to be considered in the design of the perforated wall carefully. Using resonance channels for wave energy dissipation, a new concept perforated breakwater is proposed, which is free from impact loads. Numerical simulation was made for wave reflection characteristics of the breakwater with respect to major design parameters. Numerical analysis was carried out using the Galerkin's FE model based on the linear potential theory considering energy dissipation on the perforated plate. Variations of wave reflection was investigated according to perforated ratios of perforated plate.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.4
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• pp.935-946
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• 2014

This paper investigates the noise transmission performance of industrial mufflers widely used in ships based on the CAE modeling and simulation. Since the industrial mufflers have very complicated internal structures, the conventional Transfer Matrix Method (TMM) is of limited use. The CAE modeling and simulation is therefore required to incorporate commercial softwares: CATIA for geometry modeling, MSC/PATRAN for FE meshing and LMS/SYSNOISE for analysis. Main sources of difficulties in this study are led by complicated arrangement of reactive elements, perforated walls and absorption materials. The reactive elements and absorbent materials are modeled by applying boundary conditions given by impedance. The perforated walls are modeled by applying the transfer impedance on the duplicated node mesh. The CAE approach presented in this paper is verified by comparing with the theoretical solution of a concentric-tube resonator and is applied for industrial mufflers.