• Structural Engineering and Mechanics
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• v.60 no.5
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• pp.781-794
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• 2016

Due to its relatively good safety performance and aesthetic benefits, laminated glass (LG) is increasingly being used as load-carrying members in modern buildings. This paper presents an experimental study into one applicational scenario of structural LG subjected to in-plane bending. The aim of the study is to reveal the in-plane behaviors of the LG beams made up of multi-layered glass sheets. The LG specimens respectively consisted of two, three and four plies of glass, bonded together by two prominent adhesives. A total of 26 tests were carried out. From these tests, the structural behaviors in terms of flexural stiffness, load resistance and post-breakage strength were studied in detail, whilst considering the influence of interlayer type, cross-sectional interlayer percentage and presence of shear forces. Based on the test results, analytical suggestions were made, failure modes were identified, corresponding failure mechanisms were discussed, and a rational engineering model was proposed to predict the post-breakage strength of the LG beams. The results obtained are expected to provide useful information for academic and engineering professionals in the analysis and design of LG beams bending in-plane.

• Journal of the Korean Society of Safety
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• v.23 no.3
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• pp.42-50
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• 2008

This study, push-off tests for the initially uncracked specimens were conducted to investigate shear transfer mechanism in reinforce concrete elements. Experimental programs for shear transfer were undertaken to investigate the effect of the concrete compressive strength, the presence of steel stirrups as shear reinforcement and the amount of steel stirrups. As the shear plane is loaded, several cracks form in a direction inclined to the shear plane, creating compression struts in the concrete. For this stage, shear is being transferred through a truss-like action produced by the combination of the compressive force in the concrete struts and the tensile force that the steel reinforcement crossing the shear plane develops. In the normal strength concrete specimens with steel stirrups, ultimate failure occurred when the compression struts crushed in concrete. In the high strength concrete specimens, on the other hand, ultimate failure occurred when the steel stirrups developed their yield strength.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.04a
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• pp.304-311
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• 2001

Unreinforced masonry is widely used as a structural material in residential constructions and known to have poor seismic performance in the out-of-plane rather than in-plane behavior. In countries of lower seismicity such as Korea, it is necessary to check the possibility of the mode of the out-of-plane failure. Though face loading is a major cause of the failure of masonary walls, Korean Seismic Code does not include provision for face-loaded unreinforced masonry walls. This paper briefly reviews the concept of analysis for unreinforced masonry walls subjected to face-load excitation proposed by Priestley, and its applicatility to Korean case.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.7 no.1
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• pp.27-30
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• 1977

To insure accuracy in dental roentgenographs, it is important that the patient's head position and angulation of the x-ray tube. In 1907 Cieszynski applied the rule of isometry to dental radiography and established that in the production of an accurate image of a tooth, the central ray must be porjected perpendicularly to a plane bisecting angle formed by the longitudinal axis of the tooth and the film plane. Proper exposure of the film is a part of the production of a good dental radiograph, and correct processing also makes an essential contribution to the quality of the radiograph. The author analysed the failure of exposure and processing results, and recommended followings. 1. The patient head must be positioned that occlusal plane are parallel with the horizontal floor. 2. Central ray must be projected to the objective tooth and supporting structure and projected as perpendicularly to tooth axis and film surface as possible. 3. In processing, the temperature of the solution and the processing time must be correct.

• Steel and Composite Structures
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• v.9 no.2
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• pp.173-189
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• 2009

This paper presents a study on the behavior and design of bolted stainless steel plates under in-plane tension. Using an experimentally validated finite element (FE) program strength of stainless steel bolted plates under tension is examined with an emphasis on plate bearing mode of failure. A numerical parametric study was carried out which includes examining the behavior of stainless steel plate models with various proportions, bolt locations and in two different material grades. The models were designed to fail particularly in bolt tear-out and material piling-up modes. In the numerical simulation of the models, non-linear stress-strain material behavior of stainless steel was considered by using expressions which represent the full range of strains up to the ultimate tensile strain. Using the results of the parametric study, the effect of variations in bolt positions, such as end and edge distance and bolt pitch distance on bearing resistance of stainless steel bolted plates under in-plane tension has been investigated. Finally, the results obtained are critically examined using design estimations of the currently available international design guidance.

• Geotechnical Engineering
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• v.4 no.3
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• pp.35-42
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• 1988

A series of consolidated-undrained cubical triaxial tests was performed to investigate the three- dimensional strength characteristics of anisotropic overconsolidated clay. All specimens sampled in field were loaded under conditions of principal stress directions fixed and aligned with the directions during sampling. A sufficient number of tests It was performed to deter.mine the three- dimensional failure surface in the octahedral plane. The adjusted effective friction angles obtained by the stress state projected on the same octahedral plane did not show anisotropy, while the measured effective friction angles showed considerally difference according to the axes of speccimens. Therefore, Lade failure criterion proposed fort isotropic materials could be also used practically for anisotropic overconsolidated clay. The direction of the plastic strain increment wrectors superimposed on the principal stress space was nearly perpendicular to the traces of the failure surface in the octahedral plane.

• Computers and Concrete
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• v.8 no.6
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• pp.735-755
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• 2011

The capability of a multi-directional fixed smeared crack constitutive model to simulate the flexural/punching failure modes of fiber reinforced concrete (FRC) laminar structures is discussed. The constitutive model is implemented in a computer program based on the finite element method, where the FRC laminar structures were simulated according to the Reissner-Mindlin shell theory. The shell is discretized into layers for the simulation of the membrane, bending and out-of-plane shear nonlinear behavior. A stress-strain softening diagram is proposed to reproduce, after crack initiation, the evolution of the normal crack component. The in-plane shear crack component is obtained using the concept of shear retention factor, defined by a crack-strain dependent law. To capture the punching failure mode, a softening diagram is proposed to simulate the decrease of the out-of-plane shear stress components with the increase of the corresponding shear strain components, after crack initiation. With this relatively simple approach, accurate predictions of the behavior of FRC structures failing in bending and in shear can be obtained. To assess the predictive performance of the model, a punching experimental test of a module of a façade panel fabricated with steel fiber reinforced self-compacting concrete is numerically simulated. The influence of some parameters defining the softening diagrams is discussed.

• Earthquakes and Structures
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• v.6 no.6
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• pp.689-713
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• 2014

The seismic vulnerability of stone masonry buildings is studied on the basis of their fragility curves. In order to account for out-of-plane failure modes, normally disregarded in past studies, linear static Finite Element analysis in 3D of prototype regular buildings is performed using a nonlinear biaxial failure criterion for masonry. More than 1100 analyses are carried out, so as to cover the practical range of the most important parameters, namely the number of storeys, percentage of side length in exterior walls taken up by openings, wall thickness, plan dimensions and number of interior walls, type of floor and pier height-to-length ratio. Results are presented in the form of damage and fragility curves. The fragility curves correspond well to the damage observed in masonry buildings after strong earthquakes and are in good agreement with other fragility curves in the literature. They confirm what is already known, namely that buildings with stiff floors or higher percentage of load-bearing walls are less vulnerable, and that large openings, taller storeys, larger number of storeys, higher wall slenderness and higher ratio of clear height to horizontal length of walls increase the vulnerability, but show also by how much.

• International Journal of Concrete Structures and Materials
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• v.3 no.1
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• pp.71-77
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• 2009

A theoretical model of multiple cracking failure mechanism is proposed herein for fiber reinforced high performance Cementitious composites. By introducing partial debonding energy dissipation on non-first cracking plane and fiber reinforcing parameter, the failure mechanism model of multiple cracking is established based on the equilibrium assumption of total energy dissipation on the first crack plane and non-first cracking plane. Based on the assumption of the first crack to be the final failure crack, energy dissipation terms including complete debonding energy, partial debonding energy, strain energy of steel fiber, frictional energy, and matrix fracture energy have been modified and simplified. By comparing multiple cracking number and energy dissipations with experiment results of the reference's data, it indicates that this model can describe the multiple cracking behavior of fiber reinforced high performance cementitious composites and the influence of the partial debonding term on energy dissipation is significant. The model proposed may lay a foundation for the predictions of the first cracking capacity and post cracking capacity of fiber reinforced high performance cementitious composites and also can be a reference for optimal mixture for construction cost.

• Geotechnical Engineering
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• v.6 no.1
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• pp.43-58
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• 1990

In order to get ultimate pullout resistance of ground anchor, the position of failure surface, normal stress and friction angle on the failure surface should be known. In this study, the position of failure surface is obtained by observing deformation of ground around anchor, and stresses on the anchor surface are analyzed by measuring normal and shear stresses on the anchor surface through model anchor test in plane strain. In addition, the relationship between lateral earth pressure and the position of failure surface is analyzed and the formula for calculating ultimate pullout resistance of anchor is proposed by using non-dimensional coefficient of ultimate pullout resistance.