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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of The Korean Society of Civil Engineers
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Journal DOI :
Korean Society of Civil Engeneers
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Volume & Issues
Volume 18, Issue 3_6 - Nov 1998
Volume 18, Issue 2_6 - Nov 1998
Volume 18, Issue 1_6 - Nov 1998
Volume 18, Issue 3_5 - Sep 1998
Volume 18, Issue 2_5 - Sep 1998
Volume 18, Issue 1_5 - Sep 1998
Volume 18, Issue 3_4 - Jul 1998
Volume 18, Issue 2_4 - Jul 1998
Volume 18, Issue 1_4 - Jul 1998
Volume 18, Issue 3_3 - May 1998
Volume 18, Issue 2_3 - May 1998
Volume 18, Issue 1_3 - May 1998
Volume 18, Issue 3_2 - Mar 1998
Volume 18, Issue 2_2 - Mar 1998
Volume 18, Issue 1_2 - Mar 1998
Volume 18, Issue 3_1 - Jan 1998
Volume 18, Issue 2_1 - Jan 1998
Volume 18, Issue 1_1 - Jan 1998
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Improvement of Lanczos Method for Solution of Eigenproblems of Non-Proportional Damping Systems
Kim, Man-Cheol ; Jung, Hyung-Jo ; Park, Sun-Kyu ; Lee, In-Won ;
Journal of The Korean Society of Civil Engineers, volume 18, issue 1_5, 1998, Pages 587~587
A solution method is presented to solve the eigenproblem arising in the dynamic analysis of non-proportional damping systems with symmetric matrices. The method is based on the use of Lanczos method to generate a Krylov subspace of trial vectors, which is then used to reduce a large eigenvalue problem to a much smaller one. The method retains the n order quadratic eigenproblem, without the need to use the method of matrix augmentation traditionally used to cast the problem as a linear eigenproblem of order 2n. In the process, the method preserves the sparseness and symmetry of the system matrices and does not invoke complex arithmetics, therefore, making it very economical for use in solving large problems. Numerical results are presented to demonstrate the efficiency and accuracy of the method.
A study on Deflection of Cracked Reinforced Concrete Plates based on Effective Stiffness
Choi, Wae-Ho ; Park, Woo-Jin ; Jo, Sun-Gyu ; Lee, Heung-Su ;
Journal of The Korean Society of Civil Engineers, volume 18, issue 1_5, 1998, Pages 597~597
The objective of this paper is to develop a finite element program for calculating, deflections of reinforced concrete slabs. The deflections are calculated based on the effective stiffness formulation that includes the effects of crack. The finite element model is incorporated the Serendipity plate bending element. It is an isoparametric, quadratic, degenerate element based on the assumptions of the Mindlin theory for plate bending. Concrete after cracking is considered to has an orthotropic behavior. The reduced stiffness coefficients after cracking are calculated from the effective moments of inertia in the x- and y-directions. The proposed model has found to be effective when calculation results of this study has been compared to test results.
Evaluation of Fatigue Life of RC Bridge Decks under Heavy Traffics
Chung, Chul-Hun ; Kim, Young-Jin ; Youn, Seok-Goo ;
Journal of The Korean Society of Civil Engineers, volume 18, issue 1_5, 1998, Pages 605~605
Recently, the failure case of the bridge reinforced concrete slabs have been increasing in Korea and it was observed that the failure modes of most reinforced concrete slabs collapsed were not caused by flexural moment but by local punching shear. The main reason of the failures was the fatigue failure of reinforced concrete slabs under heavy truck traffics. Therefore, the statical punching shear strength and the fatigue failure of the slab should be estimated accurately for the safety of the bridge slabs. Since current codes of pratice do not take into account the effects of the reinforcement ratio and lateral restraint of the punching strength of deck slabs, the proper design of deck slabs for such bridges requires a proper estimate of their punching strength and fatigue lifes. In this study, the domestic field experimental data, the analytical fatigue life based on the Matsui's empirical formula, and the real bridge failure case caused by the punching shear are compared.
Free Vibration Characteristics of an Inclined Cable
Ahn, Sang-Sup ; Chang, Sung-Pil ;
Journal of The Korean Society of Civil Engineers, volume 18, issue 1_5, 1998, Pages 615~615
This paper presents the characteristics of linear natural vibration of an inclined cable. To this end, the equation of motion is derived considering the effect of the cable inclination. The effect of the cable inclination can be represented by considering the chord-wise component of self-weight. The inclined cable reveals the phenomena of the formation of hybrid modes at the specific sag ratio. This is different fact from the horizontal cable. Hybrid mode affects the dynamic tension of the inclined cable in natural motion. That is, induced dynamic tension considering the effect of inclination has larger value than not considering that. And maximum values are found in different sag ratio from the horizontal cable. Also, the applicable sag ratio of the natural frequency equation can be expanded by considering the effect of the inclination. Comparisons with the previous works are presented and the results from this paper are analyzed in order to verify the results.
Dynamic Boundary Element Method of Multi-Layered Half Plane Using Asymptotic Solutions
Kim, Moon-Kyum ; Rhee, Jong-Woo ; Lee, Phil-Kyu ; Kim, Min-Kyu ;
Journal of The Korean Society of Civil Engineers, volume 18, issue 1_5, 1998, Pages 625~625
The semi-analytical method to compute the dynamic fundamental solutions for viscoelastic layered half-planes is presented. The properties of multi-layered half-plane can be expressed by generalized reflection and transmission coefficients. The fundamental solutions for dynamic line source in frequency domain can be estimated by Fourier transformation and inverse transformation with respect to horizontal wavenumber which is expressed as finite integrals. When source and receiver depths are close, it is difficult to compute the fundamental solutions of layered half-planes, because their integrands oscillate with slowly decreasing amplitude. It can be overcome using the asymptotic solutions which converge to the integrands of Green's functions with increasing wavenumber. Since their analytical solutions are expressed by the products of exponential functions and sinusoidal functions, they can be analitically integrable. The range of wavenumber integration is reduced significantly and this make the boundary element method efficient. We show the efficiency of this procedure and finally demonstrate the validity of boundary element method, to which our procedure is applied, with some cases.
Elasto-Plastic Analysis of Underground Structure by Using the Stochastic Finite Element Method
Ra, Kyeong-Woong ; Kim, Sang-Hyo ;
Journal of The Korean Society of Civil Engineers, volume 18, issue 1_5, 1998, Pages 637~637
An elasto-plastic stochastic finite element method is developed to analyze the probability of displacement and plastic region of the underground structure which has random material properties. The Mohr-Coulomb yield criterion is adopted for the failure condition. The material properties such as the elastic modulus and cohesion are assumed to be statistically independent random variables which are modeled as spatial stochastic fields. Ground displacements around the excavated area and probabilities of the corresponding plastic failure are examined by varying the coefficient of variation of each variable. The influence of the correlation distance is also examined. Displacements and plastic zones are found to be very sensitive to the probabilistic characteristics of material properties. Therefore, the safety level of excavated areas in the stochastic field should be evaluated in the probabilistic perspective for displacements and plastic regions. The correlated relationship between the displacement and the plastic failure probability obtained in this study can be utilized to predict the plastic failure from the measured displacement data around the excavated area.
Open Space Evaluation for Vibration-Attenuation of Concrete Panels with Recycled Materials
Chung, Young-Soo ; Cho, Sung-Ho ; Choi, Woo-Sung ;
Journal of The Korean Society of Civil Engineers, volume 18, issue 1_5, 1998, Pages 651~651
Vibration-controlled concrete has been developed by using various concrete mixtures, such as latex, rubber powders, plastic rosins and polystyrene(styrofoam). As part of the recycling research of obsolete aged tires and plastic materials, vibration-reducing mixtures are used for 10 concrete panels having above
in uniaxial compressive strength. Open space test has been carried out for the analysis of the impact wave, of which data have been transferred by the FFT technique to comparatively investigate damping ratios of 10 concrete panels. According to wave propagation analysis on vibration-controlled concrete for this research, it can be concluded that Latex concrete has relatively larger damping ratios than those for normal concrete with similar compressive strength.
Development of Refined Plastic-Hinge Analysis Accounting for Sequential Loads
Kim, Seung-Eock ;
Journal of The Korean Society of Civil Engineers, volume 18, issue 1_5, 1998, Pages 663~663
In this paper, the refined plastic-hinge analysis is improved to account for the effect of strain reversal induced by sequential loading. This analysis will permit sequential loading to be applied to structures as well as consider material and geometric nonlinearities. As well, the problem conventional refined plastic-hinge analyses have underestimating the strength of structures subjected to sequential loading is overcome. Efficient ways of assessing steel frame behavior including gradual yielding associated with residual stresses and flexure, second-order effect, and geometric imperfections are outlined. The modified stiffness degradation model approximating the effect of strain reversal is discussed in detail. The load-displacements predicted by the proposed analysis compare well with those given by a plastic-zone analysis, and a case study is provided for an unbraced frame. Member sizes determined by the proposed analysis are compared with those of the conventional refined plastic-hinge analysis. In conclusion the proposed analysis is presented as an efficient, reliable tool ready to be implemented into design practice.
Effect of Sand-Cap in Compressive Strength of High Strength Concrete Cylinders
Park, Young-Shik ; Suh, Jin-Kook ; Shin, Young-Shik ; Lee, Jae-Hoon ;
Journal of The Korean Society of Civil Engineers, volume 18, issue 1_5, 1998, Pages 673~673
Grinding the end of cylinder instead of bonded capping system should be used for the recognition of the compressive strength of high strength concrete, because the compressive strength by using conventional capping methods, such as sulfur mortar capping, has been underestimated. It has been ascertained from this study that the capping system by sand-cap is not only more economic in the time and the process of testing but more reliable in the results than grinding method. Also, the simple estimating equations which are able to presume the exact value for the compressive strength of high strength concrete cylinders are presented in this study, although the other conventional capping methods are used under unavoidable situation of the fields.
Cross Beam Effects on Free Vibration of Horizontally Curver I-Girder Bridges
Yoon, Ki-Yong ; Kang, Young-Jong ; Lee, Kyu-Se ;
Journal of The Korean Society of Civil Engineers, volume 18, issue 1_5, 1998, Pages 687~687
Due to the initial curvature of horizontally curved I-girder bridges, their out-of-plane behavior exhibits the flexural and torsional motion simultaneously. Unlike the dynamic and static responses of straight bridges, those of curved bridges are significantly affected by cross beams and the initial curvature of girders. In the present study, the finite element analysis is used to investigate cross beam effects on free vibration of horizontally curved I-girder bridges with varying modeling methods, degrees of freedom, cross sections and numbers. Free vibration analyses of horizontally curved I-girder bridges are performed with the finite element analysis program developed based on the theory of thin-walled curved beams. The bridge is modeled as a 3-dimensional grillage beam system composed of curved beam elements and straight beam elements. Both of those elements have 7 degrees of freedom per node including the warping degree of freedom.
Optimal Design of Plate Girder Bridges for Korean High-Speed Railway
An, Ye-Jun ; Shin, Yung-Seok ; Shin, Dong-Ku ; Seo, Sang-Sik ;
Journal of The Korean Society of Civil Engineers, volume 18, issue 1_5, 1998, Pages 699~699
Noncomposite steel plate girder bridges are optimally designed for the Korean high-speed railway bridge. Static and fatigue load cases are considered. The design variables are the thicknesses and the lengths of the plates that are used to form H-shaped stringers, cross-beams, and main girders with variable cross sections. To improve computational efficiency, a multi-level optimization scheme is used where stringers, cross beams, and main girders are individually and sequentially optimized. A C++ based design program is developed; this program interfaces with a FORTRAN based optimization program ADS. The results show that the fatigue strength in short stringer members together with the deflections of main gilders are the most important constraints in designing the high-speed railway bridge.
Flexural-Torsional Buckling Characteristics of Monosymmetric Circular Arches
Kang, Young-Jong ; Lee, Gyu-Sei ; Lim, Nam-Hyoung ; Yoon, Ki-Yong ;
Journal of The Korean Society of Civil Engineers, volume 18, issue 1_5, 1998, Pages 713~713
Because of initial curvature, the out of plane deflections perpendicular to the curvature plane are coupled with its twist rotations, and its in plane deflections are coupled with its axial deflections. Because of these coupling effects, the buckling behavior of curved beam becomes more complicated compared with straight beam. Also, the buckling behavior of monosymmetric curved beam is different from the doubly symmetric curved beam because of wagner effect. This wagner effect result in change in the effective torsional rigidity of the monosymmetric section. In the present paper, closed form solutions are obtained for arches subjected to equal and opposite end moments (uniform bending), and to uniformly distributed radial load (uniform compression). The method of assumed mode is used in determining the buckling loads. The investigation on the buckling modes of arches and the effective torsional rigidity due to wagner effect presents an insight for better understanding of buckling characteristics of arches.
A Study on the Static and Fatigue Behavior of High Tension Bolted Joints (II) - Influence of Bolt Hole Size -
Lee, Seung-Yong ; Cho, Sun-Kyu ; Chang, Dong-Il ;
Journal of The Korean Society of Civil Engineers, volume 18, issue 1_5, 1998, Pages 725~725
In field fabrication of steel members using high tension bolts, the oversize hole is frequently required due to the disagreement of bolt holes. But, there are no provisions about oversize hole in the Specifications of Korea Highway Bridge. In order to evaluate the effect of oversize holes in friction type high tension bolted joints, this study is performed with enlarging bolt hole size applicated in AASHTO and ECCS specifications. Experimental studios are divided into static and fatigue tests. The former is performed to measure the slip force and slip coefficient, the latter is performed to evaluate the fatigue strength and failure pattern of fatigue crack. In addition, relaxation tests are performed to measure the reduction of clamping force directly after clamping the high tension bolts. From the results, the variation due to the elapsed time of clamping force in oversize holes 26mm is not different from that in holes of nominal size 24mm, and decrease of the slip coefficient is negligible. The fatigue strength in oversize holes compared with holes of nominal size is almost the same.
Information Management System for Construction Management and Construction CALS by Standard Information Classification(I)
Kang, Leen-Seok ;
Journal of The Korean Society of Civil Engineers, volume 18, issue 1_5, 1998, Pages 737~737
Construction management process based on construction CALS needs to hold information in common by a standard classification code system. Since CI/SfB can be used to civil engineering projects only with great difficulty, ISO suggested a new standard of being composed of eight facets for construction information in 1994. Subsequently NBS services in London developed the Uniclass system to substitute for CI/SfB in 1997. Uniclass is the first system in accordance with the suggestion of ISO, and the items representing civil engineering projects are well classified. Considering that CI/SfB is being used in our country and that there is much to be desired in international exchange of construction information, it is necessary to analyze adaptability of Uniclass. The present study analyzed the adaptability of Uniclass comparing with CI/SfB, and then suggested that the classification system with fourteen facets can be applicable to civil engineering projects.