• Geomechanics and Engineering
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• v.29 no.6
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• pp.645-655
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• 2022

Granular columns have recently found widespread use in underground construction. The behaviour of granular columns under vertical loads has been extensively studied, specifically in relation to vertical load capacity obtained by bulging of the column body, including the behaviour after encasement of material. Determining the shear strength of loose soils reinforced with granular columns has received less attention. After the observations of lateral deformation near the toe of the embankment, attempts have been made to strengthen the lateral strength of granular columns. The purpose of this research is to look into the effects of different encasement conditions on the lateral load capacity of granular columns. This was accomplished by three-dimensional finite element analysis with FEM software. Various normal pressures and two different encasement configurations, namely single layer encasement and double layer encasement, with differing tensile strengths, were used in this study to determine their effect on lateral resistance. The failure envelope for a single column planted in loose sand was used to analyse the findings for three different granular column diameters, as well as the impact of different encasement conditions. According to the findings, the inclusion of a Granular Column enhanced the shear strength and overall stiffness of the loose sand bed, and the encasement of the Granular Column helped in deriving higher lateral resistance.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.3
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• pp.95-104
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• 2007

This study was focused on the effect of concrete strength and lateral ties of concrete columns subjected to eccentric compressive loads. The twenty-four concrete columns with $200mm{\times}200mm$ square cross-section were tested. The main variables were concrete strength, spacing and configuration of lateral ties, and eccentricity ratios. From the experiment, the followings were investigated ; 1) In all cases, it was observed that the increase of concrete compressive strength led to the decrease of ductility. Also, as the eccentricity ratios increased, the effect of ductility enhancement by lateral ties decreased. 2) As the ties spacing decreased from 100mm to 30mm, the magnitude of axial load acting on the concrete column showed an enhancement of 1.1~1.2 times and the descending curve after a peak moment presented a smooth decline. 3) The high-strength concrete columns required a design of lateral ties to increase the volumetric ratios and density of tie spacing to sustain a proper strength and ductility. Accordingly, regardless of concrete strength, the current AIK design code to specify the maximum tie spacing of concrete columns was proven to lead to the poor strength and ductility for seismic design. Therefore, it is necessary to develop a new seismic design code that connects volumetric ratios and tie spacing of concrete columns with concrete strength.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.9
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• pp.1175-1183
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• 2010

A spacer grid assembly is one of the most important structural components in a Light Water Reactor(LWR) nuclear fuel assembly. In the case of the Zircaloy spacer grid assembly, the primary design consideration is to ensure that lateral dynamic crush strength of the spacer grid assembly is sufficient to resist design basis loads and thereby prevent seismic accidents, without a significant increase in the hydraulic head loss for the reactor coolant in the reactor core. In this study, factors affecting the lateral dynamic crush strength of a spacer grid assembly were analyzed by performing lateral dynamic crush tests and finite element analyses. Further, an effective and economical method to enhance the lateral dynamic crush strength of the spacer grid assembly is proposed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.4
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• pp.99-108
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• 2007

In the flat-plate slab design of the KCI and ACI building code, the punching shear strength of connections with shear reinforcement can increase one and half times to that of connections without shear reinforcement. And the ACI-ASCE committee 352 recommendations propose limiting the direct shear ratio $V_g$/$V_c$ on interior connections to 0.4 to insure adequate drift capacity. In this study, four interior column-slab connections were tested to look into the punching shear strength and the lateral displacement capacity of the flat-plate slab with and without shear reinforcement under cyclic lateral loading. Based on the test results, it is found that the provision about punching shear strength in the codes may appropriate for the gravity loading only whereas it is unconservative for the lateral loading and that the limit of ACI-ASCE committee 352 appears conservative.

• Structural Engineering and Mechanics
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• v.68 no.3
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• pp.289-297
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• 2018

The real behavior of the RC structures constructed based on the assumed specifications of the used materials is matched with the designed ones when the assumed and the applied specifications in construction are the same. Despite in the construction phase of the reinforced concrete (RC) structures always it is tried to implement the same specifications of materials as given in the executive drawings, but considering the unpredicted/uncontrolled parameters that affect the specification of materials, always there is a deviation between the constructed and the designed materials' specifications. The objective of this paper is to submit a guideline for the evaluation of the strength and damage to the existing RC structures encountered deviation in materials' strengths. To achieve this goal, the lateral strength (plastic behaviors) and damage to twenty-five RC moment-resisting frames (MRFs) are studied by applying the inelastic analysis. In this study, a couple of concrete and reinforcement strengths' deviations are investigated. The obtained results indicate that in general, there is a semi-linear relationship between the deviation in the strength of reinforcement and the changes in the lateral strength values of the MRFs. The relative effect of the deviation in the strength of reinforcements is more than the relative effect of the deviation in the concrete strength on the damage rate. The obtained results could be a guideline for the engineers in the survey of the existing buildings encountered deviation in materials' strengths during their construction phase.

• Proceedings of the KSR Conference
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• 2002.10b
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• pp.892-897
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• 2002

The research was requested by Meridian Rail Corporation in United States. The Swing Motion Bogie can application by Korea style if synthesize study result of bogie strength evaluation, bogie dynamic characteristics analysis, actual test(maximum speed, derailment coefficient, lateral force, vertical force, vibration acceleration, steady state lateral acceleration) etc..

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.411-416
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• 2000

The behavior of high strength reinforced concrete columns subjected to uniaxal reversal loading and biaxial reversal circle path loading was investigated. Four full scale test specimens were tested. All specimens were adopted cantilever type, in order that the critical region is to locate only at the bottom of column. The parameters studied were transverse reinforcement ratio, uniaxial lateral loading and biaxial lateral loading. The damage features of columns by the biaxial loading are different from those of the uniaxial loading, However, the maximum strength and the draft angle at maximum strength were almost the same under uniaxial and biaxial loading. The transverse reinforcement under biaxial loading was very effective for increasing ductility of specimens.

• Earthquakes and Structures
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• v.12 no.4
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• pp.449-455
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• 2017

Using X-braced frames in steel structures is a current procedure to achieve good strength against lateral loads. Study on mid-connections of X-braces and their effects on frame behavior is a subject whose importance has been more or less disregarded by researchers. Experimentally inspecting models involves considerable expense and time; however, computer models can be more suitable substitutes. In this research, a numerical model of X-braced frame has been analyzed using finite element software. The results of pushover analysis of this frame are compared with those of the experimental test. With the help of computer model, the effects of different mid-connection details on ductility and lateral strength of the frame are inspected. Also performances of bolted and welded connections are compared. Taking into account ductility and strength, this study suggests details of a decent pattern for the mid-connection.

• Steel and Composite Structures
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• v.33 no.2
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• pp.245-259
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• 2019

The present study aims to investigate the ultimate strength and geometric nonlinear behavior of composite plates containing initial imperfection subjected to combined end-shortening strain and lateral pressure loading by using a semi-analytical method. In this study, the first order shear deformation plate theory is considered with the assumption of large deflections. Regarding in-plane boundary conditions, two adjacent edges of the laminates are completely held while the two others can move straightly. The formulations are based on the concept of the principle of minimum potential energy and Newton-Raphson technique is employed to solve the nonlinear set of algebraic equations. In addition, Hashin failure criteria are selected to predict the failures. Further, two distinct models are assumed to reduce the mechanical properties of the failure location, complete ply degradation model, and ply region degradation model. Degrading the material properties is assumed to be instantaneous. Finally, laminates having a wide range of thicknesses and initial geometric imperfections with different intensities of pressure load are analyzed and discuss how the ultimate strength of the plates changes.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.129-134
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• 2003

The importance of understanding the response of structural composites to impact and CAI cannot be overstated to develop analytical models for impact damage and CAI strength predictions. This paper presents experimental findings observed from quasi-static lateral load tests, low velocity impact tests, CAI strength and open hole compressive strength tests using 3mm thick composite plates ($[45/-45/0/90]_{3s}$ - IM7/8552). The conclusion is drawn that damage areas for both quasi-static lateral load and impact tests are similar and the curves of several drop weight impacts with varying energy levels (between 5.4 J and 18.7 J) fallow the static curve well. In addition, at a given energy the peak force is in good agreement between the static and impact cases. From the CAI strength and open hole compressive strength tests, it is identified that the failure behaviour of the specimens was very similar to that observed in laminated plates with open holes under compression loading. The residual strengths are in good agreement with the measured open hole compressive strengths, considering the impact damage site as an equivalent hole. The experimental findings suggest that simple analytical models for the prediction of impact damage area and CAI strength can be developed on the basis of the failure mechanism observed from the experimental tests.