• Structural Engineering and Mechanics
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• v.51 no.3
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• pp.471-485
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• 2014

Until now, the finite corner stiffness of the right-angle frames used as horizontal girders in a bonnet, have not been considered during the design process to result in not a precise result. This paper presents a design equation set for right-angle frames used as horizontal girders in a bonnet assuming rigid corner stiffness. By comparing the center stresses of the right-angle frame according to the design equation set with the results of the finite element method, the master curves for the empirical corner stiffness can be determined as a function of slenderness ratio. A second design equation set for a right-angle frame assuming finite corner stiffness was derived and compared with the first equation set. The master curves for the corner stiffness and the second design equation set can be used to determine the design moments at the centers of the girder so that the bending stresses can be analyzed more precisely.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.04a
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• pp.487-495
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• 2003

Bearings at the obtuse corner are subjected to much larger vertical reactions than other bearings because of the geometric shape of skew bridges. The current relevant specifications require that additional bars should be disposed at the bottom of concrete deck slabs to deal with the large vertical reaction on bearings at the obtuse corner. In this study, new methods of reducing the magnitude of the vertical reaction on bearings at the obtuse corner by the stiffness adjustment of bearings were proposed. The basic concept of proposed methods was to redistribute support reactions by reducing the vertical stiffness of bearings at the obtuse corner showing a relatively large vertical reaction. For 45 simply supported skew bridges designed according to the current relevant specifications, the redistribution effect of vertical reactions by the stiffness adjustment of bearings was investigated. Parameters such as skew angle, girder spacing, and deck aspect ratio that affect the distribution of support reactions were considered. The results of the analyses show that the magnitude of the vertical reaction on bearings at the obtuse corner can be reduced to the levels of straight bridges by replacing the existing bearings at the obtuse corner with new ones having the value of 1/10 or 1/20 of the vertical stiffness of the existing bearings. The reduction effect of the vertical reaction on bearings at the obtuse corner increases as the girder spacing decreases and it is more pronounced when the deck aspect ratio is 2.0.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.939-940
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• 2013

• Journal of the Korean Geosynthetics Society
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• v.21 no.2
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• pp.39-48
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• 2022

Unlike the horizontal strut, the corner strut causes bending behavior by the installation angle when soil pressure occurs, so there is a limit to its application as a elasto plastic method that requires only the axial stiffness of struts. Therefore, this study attempted to approach a method of modifying axial stiffness data to present an analysis method for corner struts in elasto plastic method, and linear elasticity analysis was used for this. And, through Linear elasticity analysis, axial stiffness data for corner struts installed at the actual site were calculated. The behavior of the retainingwall was confirmed by applying the calculated axial stiffness data of corner struts to elasto plastic method, and its applicability was evaluated by comparing it with the measurement results and the finite element analysis results. As a result of the study, when the axial stiffness data of the corner struts was applied using Linear elasticity analysis(Case 1, Case 3), the axial stiffness data decreased to 9% to 17% compared to the general method of applying the axial stiffness of the struts(Case 2, Case 4), and the displacement of the retainingwall increased to 25.33% to 64.42%. Comparing this result with the measurement results, when Linear elasticity analysis was used(Case 1, Case 3), the behavior of the retainingwall during the elasto plastic method was better shown.

• Steel and Composite Structures
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• v.48 no.3
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• pp.321-333
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• 2023

This paper proposes a comprehensive investigation on lateral stiffness of corner-supported steel modular frame using splice connection. A full-scale modular frame with two stacked steel modules under lateral load is tested. Ductile pattern in the transfer of lateral load is found in the final failure mode. Two types of lateral stiffness, including tangent stiffness and secant stiffness, are defined from the load-displacement due to the observed nonlinearity. The difference between these two types of stiffness is found around 20%. The comparisons between the experimental lateral stiffness and the predictions of classical methods are also conducted. The D-value method using hypothesis of independent case is a conservative option for predicting lateral stiffness, which is more recommended than method of contraflexural bending moment. Analyses on two classical short-rod models, including fix-rod model and pin-rod model, are further conducted. Results indicate that fix-rod model is more recommended than pin-rod model to simplify splice connection for simulation on lateral stiffness of modular frame in elastic design stage.

• Earthquakes and Structures
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• v.7 no.5
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• pp.891-906
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• 2014

The purpose of this study is to propose a modification factor to reflect the lateral stiffness modification when a step is located in flat plates. Reinforced concrete slabs with steps have different structural characteristics that are demonstrated by a series of structural experiment and nonlinear analyses. The corner at the step is weak and flexible, and the associated rotational stiffness degradation at the corner of the step is identified through analyses of 6 types of models using a nonlinear finite element program. Then a systematic analysis of stiffness changes is performed using a linear finite element procedure along with rotational springs. The lateral stiffness of reinforced concrete flat plates with steps is mainly affected by the step length, location, thickness and height. Therefore, a single modification factor for each of these variables is obtained, while other variables are constrained. When multiple variables are considered, each single modification factor is multiplied by the other. Such a method is verified by a comparative analysis. Finally, a complex modification factor can be applied to the existing effective slab width.

• Journal of the Korean Wood Science and Technology
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• v.17 no.2
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• pp.34-64
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• 1989

Corner block with anchor bolt(CBA) joint method used in knock-down type table furniture manufacturing can reduce the packing and transporting cost. Unfortunately. it also has the disastrous defect to be loosend and unstable during the service life mainly due to fatigue and creep(repeated and prolonged loading). So 22 joint groups constructed were tested to evaluate the effect of some design factors related to the size of side rail(apron). block attachment to side rail. and the number of anchor bolt as well as the effect of the type of corner block(mitered type vs. rectangular type) Usable strength from the stiffness coefficients of each joint group were analysed with SPSS /PC+ and described as the criteria of CBA joint construction. The conclusions were as follows: The height of side rail(50, 75 and 100 mm) and the addition of polyvinyl acetate(PVAc) emulsion in the corner block attactment to side rail had the effect on raising the usable strength of CBA joint with remarkable high significance. And the effect of 2 - anchor bolts was also superior to that of 1 - bolt significantly. However. the thickness of side rail(22 mm vs. 25 mm) had no effect on the strengthening the table joint rigidity. Mitered type corner block joint appeared to he recommendable for CBA jointed table construction rather than the rectangular type one regardless of the method of block attachment to side rail. The best result identified from Duncan's multiple comparison was in the construction with 25 mm thick and 100 mm height of side rail fastened using 2 - anchor bolts in mitered type corner block. But it would be reasonable to use 22 mm thick & 75 mm high side rail and mitered corner block with PVAc emulsion & 2 bolts considering the productivity and production cost down in the MDF furniture manufacturing industries.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.04a
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• pp.325-331
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• 2004

Generally, the buckling of thin-walled structures has studied for rectangular sections or circular sections. Rectangular sections have small stiffness and circular sections have large stiffness when they are compared with rectangular sections for local buckling. But both of them have similar stiffness to column buckling. Therefore in this paper, we are going to analyze the local buckling for the box section with rounded comer and compare with rectangular section. Also we confirm that the rounded comer section has larger local buckling strength than rectangular section.

• Geomechanics and Engineering
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• v.38 no.4
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• pp.381-395
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• 2024

With the wide application of urban subway tunnels, the foundation pits of new stations and existing subway tunnels are becoming increasingly close, and even zero-distance close-fitting construction has taken place. To optimize the construction support scheme, the existing tunnel's vertical displacement is theoretically analyzed using the two-stage analysis method to understand the action mechanism of the construction of zero-distance deep large foundation pits on both sides of the existing stations; a three-dimensional numerical calculation is also performed for further analysis. First, the additional stress field on the existing tunnel caused by the unloading of zero-distance foundation pits on both sides of the tunnel is derived based on the Mindlin stress solution of a semi-infinite elastic body under internal load. Then, considering the existing subway tunnel's joints, shear stiffness, and shear soil deformation effect, the tunnel is regarded as a Timoshenko beam placed on the Kerr foundation; a sixth-order differential control equation of the tunnel under the action of additional stress is subsequently established for solving the vertical displacement of the tunnel. These theoretical calculation results are then compared with the numerical simulation results and monitoring data. Finally, an optimized foundation pit support scheme is obtained considering the pit corner effect and external corner failure mode. The research shows a high consistency between the monitoring data,analytical and numerical solution, and the closer the tunnel is to the foundation pit, the more uplift deformation will occur. The internal corner of the foundation pit can restrain the deformation of the tunnel and the retaining structure, while the external corner can cause local stress concentration on the diaphragm wall. The proposed optimization scheme can effectively reduce construction costs while meeting the safety requirements of foundation pit support structures.

• Journal of the Korean Institute of Gas
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• v.13 no.6
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• pp.9-14
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• 2009

In this study, the stress and deformation characteristics of corner protection in which is fabricated in an insulation area have been analyzed using a finite element method. The proposed corner protection may increase the strength and leakage safeties of conventional LNG storage system. The stress and deformation of LNG storage tank system are computed for an insulation panel box, membrane inner tank, and prestressed concrete outer tank. The FEM computed results indicate that the stress and displacement of new membrane LNG tank system with a corner protection between an inner tank and an outer tank are reduced in comparison to those of a conventional membrane LNG tank. This is explained that the strength safety of LNG membrane tank system may be increased due to a strength stiffness of a corner protection.