• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.1
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• pp.227-238
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• 2003

Due to deterioration of bridge, usually be using the external prestressing method among repair reinforcement method. But, there is much to be desired about a detailed account, almost it has analysed by cambers of girders, deflections of middle span and upper, bottom stresses of girders. Also, it is not examined closely that effect of internal prestress by external prestressing. The purpose of this study is confirmed the effect of internal tendons by external prestressing, estimation of additional external prestressing force and look for exact external prestressing force.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.72-75
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• 1994

In this paper, a novel method to figure out the relative residual stress distribution along the depth of silicon diaphragms is presented Cantilevers with various thickness are fabricated by the time controlled etching method using EPW as an etchant. The boron concentration along the depth of the cantilevers is obtained by the TSUPREM IV simulation, and the etching time to get the proper thickness is calculated. By measuring deflections of the p+ silicon cantilevers the stress profile along the depth of diaphragm is calculated. The obtained stress profile is reasonable and useful to expect the deflection of cantilevers and the buckling of diaphragms.

• Structural Engineering and Mechanics
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• v.10 no.5
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• pp.463-478
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• 2000

An iterative procedure for the analysis of reinforced concrete frames with beams in cracked state is presented. ACI and CEB model equations are used for the effective moment of inertia of the cracked members. In the analysis, shear deformations are taken into account and reduced shear stiffness is considered by using effective shear modulus models available in the literature. Based on the aforementioned procedure, a computer program has been developed. The results of the computer program have been compared with the experimental results available in the literature and found to be in good agreement. Finally, a parametric study is carried out on a two story reinforced concrete frame.

• Smart Structures and Systems
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• v.15 no.5
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• pp.1177-1202
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• 2015

The present paper is concerned with the optimal control and/or design of symmetric and antisymmetric composite laminate with two piezoelectric layers bonded to the opposite surfaces of the laminate, and placed symmetrically with respect to the middle plane. For the optimal control problem, Liapunov-Bellman theory is used to minimize the dynamic response of the laminate. The dynamic response of the laminate comprises a weight sum of the control objective (the total vibrational energy) and a penalty functional including the control force. Simultaneously with the active control, thicknesses and the orientation angles of layers are taken as design variables to achieve optimum design. The formulation is based on various plate theories for various boundary conditions. Explicit solutions for the control function and controlled deflections are obtained in forms of double series. Numerical results are given to demonstrate the effectiveness of the proposed control and design mechanism, and to investigate the effects of various laminate parameters on the control and design process.

• Structural Engineering and Mechanics
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• v.43 no.2
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• pp.253-271
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• 2012

To analyze the bending and transverse shear effects of laminated composite plates, a thirteen nodes triangular element will be presented. The suggested formulations consider a parabolic variation of the transverse shear strains through the thickness. As a result, there is no need to use shear correction coefficients in computing the shear stresses. The proposed element can model both thin and thick plates without any problems, such as shear locking and spurious modes. Moreover, the effectiveness of $w_{,n}$, as an independent degree of freedom, is concluded by the present study. To perform the accuracy tests, several examples will be solved. Numerical results for the orthotropic materials with different boundary conditions, shapes, number of layers, thickness ratios and fiber orientations will be presented. The suggested element calculates the deflections and stresses more accurate than those available in the literature.

• Structural Engineering and Mechanics
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• v.44 no.3
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• pp.405-416
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• 2012

In this study the investigation of large deflections subject in compliant mechanisms is presented using homotopy perturbation method (HPM). The main purpose is to propose a convenient method of solution for the large deflection problem in compliant mechanisms in order to overcome the difficulty and complexity of conventional methods, as well as for the purpose of mathematical modeling and optimization. For simplicity, a cantilever beam of linear elastic material under horizontal, vertical and bending moment end point load is considered. The results show that the applied method is very accurate and capable for cantilever beams and can be used for a large category of practical problems for the aim of optimization. Also the consequence of effective parameters on the large deflection is analyzed and presented.

• Structural Engineering and Mechanics
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• v.42 no.5
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• pp.729-745
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• 2012

This study presents dynamic analysis of laminated beams traversed by moving loads using a multilayered beam element based on the first-order shear deformation theory. The present element consists of N layers with different thickness and material property, and has (3N + 7) degrees of freedom corresponding three axial, four transversal, and 3N rotational displacements. Delamination and interfacial slip are not allowed. Comparisons with analytical and/or numerical results available in literature for some illustrative examples are made. Numerical results for natural frequencies, deflections and stresses of laminated beams are given to explain the effect of load speed, lamina layup, and boundary conditions.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.10a
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• pp.375-382
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• 2001

This study is attempted to predict experimentally the fatigue crack propagation behavior of two-span beams with steel fibrous for various steel fibrous contents. The static tests and the fatigue tests were performed on a series of SFRC(steel fibrous reinforced concrete) to investigate the fatigue behavior of SFRC varying with the steel fibrous contents. Through this test, the diagonal cracking loads, ultimate loads, deflections, strains of concrete and steels. Fatigue crack length were measured by the eye-observation. As a result of test, A model for S-N relationship, and propagation life of fatigue crack of SFRC was proposed. The crack growth and failure of SFRC beams were studied.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.10a
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• pp.489-496
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• 1998

The single layer latticed domes have various behaviors with each geometrical shape and scale, and they are affected by vertical component as well as horizontal component of the dynamic load. And they represent ye different earthquake responses under each ground acceleration compared with another structural systems. Generally, all of the members of latticed domes undergo three dimensional deflections if they are subjected to arbitrary one dimensional horizontal load under earthquake motions. And their response characteristics are very different to their shapes, rise/span ratios, and damping mechanisms. In this study, the earthquake response behavior is verified according to the factor of each shape, rise/span ratio, and damping ratio of latticed domes, which undergo horizontal and vertical earthquake motions by numerical approaches.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1995.10a
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• pp.207-214
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• 1995

Muller-Scordelis RC Gabled Hyperbolic Paraboloid (HP) shell is divided by 40 40 mesh and analyzed using a finite element computer program which was developed by Mahamoud and Gupta and migrated to a Cray Y-U 00 at SERI. The results are compared with membrane theory and Muller-Scordelis's results. Comparing with Muller-Scordelis's result it shows that good agreements between two analyses, except a discrepancy in the normal deflections of the crown beam. The behavior of the crown beam is quite sensitive and needs further study. The analysis shows that Gabled HP shells do not behave as the typical shells according to the membrane theory. To design such Gabled HP shells we rather use a finite element analysis which simulates realistically membrane and honing actions of the shells.