• Journal of Korean Society of Steel Construction
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• v.18 no.2
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• pp.181-189
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• 2006

This study analyzes the effects of the curvature friction coefficient, the wobble friction coefficient, and the increased strength of concrete, reinforced tendon on optimum de signs by using the optimum-design program, to minimize the cost of a PSC box girder bridge using the full staging method. The objective of this study is to find a proper tendon for the friction coefficient, and thereafter, to indicate the direction of the study development about tendons and to indicate the direction of a study on the increased strength of used materials. This program used the SUMT procedure and Kavlie's extended-penalty function to allow infeasible design points in the process. Powel's direct method was used in searching design points, and the gradient approximate method was used to reduce the design hours.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.3
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• pp.309-318
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• 2004

This research automatically designed psc-box girder bridges by using an optimum design program and applied the results to the various types of bridges to verify if common facts used in steel bridges or concrete bridges can be applied to PSC bridges. Namely, it investigated appropriate unequal span length division by comparing with bridge of unequal and equal span length division, and verified the influence of the load factors which are changed by time or specification applying the results to various types of bridge. and it applied reinforced concrete bridge and steel bridge's variable girder depth which is slender and effective to save material costs to PSC box girder bridges. Technical solution of optimum design program used SUMT procedure, and Kavlie's extended penalty function to allow infeasible design points in the process. Powell's direct method was used for searching design points and a gradient's approximate method was used to reduce the design time.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.3
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• pp.159-167
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• 2004

The objective of this study is development of the optimum design program to minimize the cost for PSC box girder bridge using the full staging method to indicate the necessity for the optimum design applied many types of bridges. It also considered the proper span length to girder depth ratio and the cell number along the width of bridge. This program used SUMT procedure and Kavlie's extended penalty function to allow infeasible design points in the process. Powell's direct method was used in searching design points and Gradient Approximate Method was used to reduce design hours. This study showed the convergence in design parameter and correlation of totally optimized cost according to cell numbers, span lengths, and lane numbers.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.3
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• pp.175-185
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• 2006

This study performed the optimum design of balanced and unbalanced span length bridges with many variable Girder types by using the optimum design program to minimize the cost for PSC box girder bridge of the full staging method. The objective of this study is to present tendon's application direction about complicated construction hereafter by studying about optimum tendon arrangement that is worked in each variable Girder type. This program used SUMT procedure and Kavlie's extended penalty function to allow infeasible design points in the process. Powell's direct method was used in searching design points and Gradient Approximate Method was used to reduce design hours.

• Journal of Korean Society of Steel Construction
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• v.16 no.1 s.68
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• pp.21-32
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• 2004

In this study, a continuous optimum design model with its application program for plane steel frame structures developed. In the model, the sequential unconstrained minimization technique (SUMT) transforming the nonlinear optimization problem with multidesign variables and constraints into an unconstrained minimization problem and the refined plastic hinge analysis method as one of the most effective second-order inelastic analysis methods for steel frame structures were implemented. The total weight of a steel frame structure was taken as the objective function, and the AISC-LRFD code requirements for the local and member buckling, flexural strength, shear strength, axial strength and size of the cross-sectional shapes of members were used for the derivation of constraint equations. To verify the appropriateness of the present model, the optimum designs of serveral plane steel frame structures subject to vertical and horizontal loads were conducted.

• Journal of Korean Association for Spatial Structures
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• v.5 no.4 s.18
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• pp.61-70
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• 2005

In paper the discrete optimum design program was developed using the continuous and discrete optimum algorithms based on the SUMT and genetic algorithms. In this paper, the objective function is the weight of structures and the constraints are limits state design limits method. The design variables are diameter and thick of steel pipe. Design examples are given to show the applicability of the optimum design using the continuous and discrete optimum algorithms based on the SUMT and genetic algorithms of this study.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.1
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• pp.135-142
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• 2008

This study is concerned with the optimum design of LB-Deck plate girder bridge. The optimizing problems of the composite bridge are formulated with objective functions and constraints. The objective functions are formulated as the total cost of the concrete deck and steel girder construction and the constraints are derived by criteria with respect to the Korean Highway bridge design. The optimizing algorithm using SUMT for optimum design of the Simple span, 2-Span, 3-span LB-deck plate and general RC-steel composite girder bridges (L=60m) which act live load(DB24). And their optimum numerical results are compares and analyzed to examine the possibility of optimization, the application and convergency of this optimizing algorithm.

• Journal of Korean Society of Steel Construction
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• v.12 no.5 s.48
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• pp.515-525
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• 2000

The purpose of this paper was to develop size & shape optimization programming algorithm of plane trusses. The optimum techniques applied in this study were extended penalty method of Sequential Unconstrained Minimization Techniques(SUMT) and direct search method with multi-variables proposed by Hooke & Jeeves. Upper mentioned two methods were used iteratively at each level of size and shape optimization routines. The design variables of size optimization were circular steel tube(structural member) diameter and thickness, those of shape optimization were joint coordinates, and the objective function was represented as total weight of truss. During the optimum design, two level procedures of size and shape optimization were interacted iteratively until the final optimum values were attained. At the previous studies about shape optimization of truss, the member sectional areas and coordinates were applied as design variables. So that they could not apply the buckling effect of compression member. In this paper, actual sizes of member and nodal coordinates are used as design variables to consider the buckling effect of compression member properly.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.6 s.58
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• pp.204-211
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• 2009

In this study, the optimal method is applied to strengthening of RC hollow slab bridges using external prestressing. The Queen-post and King-post shapes are considered to find the effective tendon configurations. In order to achieve the objective rating factor, the optimal configurations and tendon forces are obtained by using the Sequential Unconstrained Minimization Technique (SUMT). The object function for optimal strengthening is constituted with the dimensionless function of material costs. The constraints are formulated by design specification and the rating factor. The validity of this study is presented by the analysis of the results of strengthening of the RC hollow slab bridges.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.4
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• pp.97-107
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• 2006

This study is structural analysis and continuous, discrete optimum design of braced steel frame structures under earthquake loads considering soil condition. The program which is able to perform simultaneously structural analysis and continuous, discrete optimum design, it is applied steel frame structures using unbraced, Z-braced, and X-braced types and analyze the program about static loads and seismic loads. The purpose of this study is to present proper braced type for seismic effects by comparing and analyzing results of analytic method about various cases using specially Newmark-Hall design spectrum, ATC design spectrum and ATC equivalent static analysis and finding minimum weight and design variables which satisfy the ultimate strength requirements of AISC-ASD specifications, the serviceability requirements and allowable story drift requirements of ATC-3-06 and various constraints.