• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.1
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• pp.55-68
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• 1991

In this study, Mixed coordination method was selected to optimize the shape of the truss structures which takes multi-loading condition, allowable stress, buckling stress, displacement constraints into consideration. The structure was devided into substructures by Goal coordination method and the substructures were optimized by model coordination method which used two-level technique. Therefore the number of design variables and constrints can be decreased considerable. Under the condition of the same disign, the weight of truss structures can be decreased more considerable by means of optimizing even the shape of truss than by means of optimizing the section of truss while fixing geometrical configuration of it, even though there might be a little difference according to the early geomatrical shape of the truss and the design condition. Thus, the shape optimization of truss structures which utilize the results of this study can be helpful to the economical design of truss structures.

• Structural Engineering and Mechanics
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• v.6 no.8
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• pp.871-882
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• 1998

This paper presents a new design method of truss bridges using advanced analysis. In this approach, separate member capacity checks encompassed by the specification equations are not required because the stability of separate members and the structure as a whole can be treated rigorously for the determination of the maximum strength of the structures. The method is developed and refined by modifications to the conventional elastic-plastic hinge method. Verification studies are carried out by comparing with the plastic-zone solutions. The load-deflection behavior of the truss shows a good agreement between the plastic-zone analysis. A case study is provided for a truss bridge. Member sizes determined by the proposed method are compared with those determined by the conventional method. It is concluded that the proposed method is suitable for adoption in practice.

• Journal of the Korean Society for Advanced Composite Structures
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• v.7 no.1
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• pp.9-18
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• 2016

In this paper, the structural characteristics of a lightweight soundproof tunnel to reduce the dead load imposed on the bridge are investigated. Subsequently, the design procedure of soundproof tunnel structures is reviewed and a design practice for the lightweight soundproof tunnel is carried out according to the reviewed procedure. Next, design compatibility for the lightweight soundproof tunnel is verified through a detailed finite element analysis. The result for evaluation of design compatibility shows that the lightweight soundproof tunnel has structural safety in structural members, welding zones and foundation parts. It is also confirmed that serviceability and buckling safety is excellent.

• Journal of Korean Association for Spatial Structures
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• v.12 no.2
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• pp.89-98
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• 2012

This study investigates the optimum structural design of space truss considering global buckling, and is to obtain the minimal weight of the structure. The mathematical programming method is used for optimization of each member by member force. Besides, dynamic programming method is adapted for consideration in snap-through buckling. The mathematical modeling for optimum design of truss members consists of objective function of total weight and constrain equations of allowable tensile (or compressive) stress and slenderness. The tangential stiffness matrix is examined to find the critical point on equilibrium path, and a ratio of the buckling load to design load is reflected in iteration procedures of dynamic programming method to adjust the stiffness of space truss. The star dome is examined to verify the proposed optimum design processor. The numerical results of the model are conversed well and satisfied all constrains. This processor is a relatively simple method to carry out optimum design with consideration in global buckling, and is viable in practice with respect to structural design.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.325-328
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• 2006

Joint structures of composite truss bridges can have the same details for the connection between diagonal members and upper concrete slab as the connection between diagonal members and lower concrete slab. Adequate connection details should be decided according to design codes, constructibility, and economical evaluation. It is necessary to clarify the design check items and load transferring mechanism because combined external loads on composite truss bridges are concentrated at the joints. Joints with gusset plates and stud connectors are applied and complicated joint details may arise some problems in construction. This paper deals with experimental evaluation of the joints in composite truss bridges and proper design provisions were investigated to enhance the details. Push-out test specimens with group studs were fabricated and the effects of grouping and bent studs were studied.

• Structural Engineering and Mechanics
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• v.44 no.3
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• pp.379-403
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• 2012

In recent years, the need for optimal design of structures under time-history loading aroused great attention in researchers. The main problem in this field is the extremely high computational demand of time-history analyses, which may convert the solution algorithm to an illogical one. In this paper, a new framework is developed to solve the size optimization problem of steel truss structures subjected to ground motions. In order to solve this problem, the covariance matrix adaptation evolution strategy algorithm is employed for the optimization procedure, while a generalized regression neural network is utilized as a meta-model for fitness approximation. Moreover, the computational cost of time-history analysis is decreased through a wavelet analysis. Capability and efficiency of the proposed framework is investigated via two design examples, comprising of a tower truss and a footbridge truss.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.3
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• pp.141-154
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• 1987

The algorithm proposed utilizes the tow-levels technique. In the first level which consists of teeatment only the applied load and design stress as the random variables whose parent distribution has the normal distribution, the cross-sectional areas of the truss members such that the their probabilities of failure have the preseribed failure probabilites are optimized by transforming the nonlinear problem into SUMT, and solving it utilizing modified Newton-Raphson method. In the second level, the geometric shape of truss structure is optimized by utilizing the unidirectional search technique of Powell method which makes it possible to minimize only the objective function. The algorithm proposed is numerically tested for the several truss structures with various shapes and loading conditions. The numerical analysis shows that the rate of decreasing the weight of truss structures is dependent on the prescribed failure probability of the each member of truss structure and the covariance of the applied load and design stress.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.10a
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• pp.171-178
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• 2004

The purpose of optimum design for structures is to minimize the cost and to obtain the reasonable structural systems. This design algorithm have many objective functions including discrete variables as sections, weight, stiffness and shapes. Simulated annealing, Genetic algorithm and TABU algorithm are used search for these optimum values in the structural design. TABU algorithm is applied to many types structures to search for section and distribution optimization and compared with the results of Genetic algorithm for evaluating the efficiency of this algorithm. In this paper, the plane truss of 10 elements and the space truss of 25 element having 10 nodes, star dome and cable dome are analyzed as analytical models.

• Steel and Composite Structures
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• v.24 no.3
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• pp.383-391
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• 2017

The goal of this study is to investigate structural analysis and behaviors of an innovative aerial work platform truss frame whose ductility is improved by using high strength-steel UL-700. The present space truss frame can move or stop through tunnels for maintenance constructions by automatic facilities and workmanship within standardized limited building lines of tunnel. Most of all, this method overcomes problematic, which is to block cars during construction periods, seriously, of typical methods like as using truck and scaffolds for tunnel maintenance. According to evaluated appropriate design results of space truss frames of numerical examples by using a commercial MIDAS GEN program, it is verified that design parameters such as layered size, cross-sectional size, and steel material of the present space truss frame are determined to depend on characteristics such as lanes or shape of road tunnels.

• Steel and Composite Structures
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• v.24 no.4
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• pp.513-521
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• 2017

The goal of this study is to investigate structural analysis and behaviors of an innovative aerial work platform truss frame whose ductility is improved by using high strength-steel UL-700. The present space truss frame can move or stop through tunnels for maintenance constructions by automatic facilities and workmanship within standardized limited building lines of tunnel. Most of all, this method overcomes problematic, which is to block cars during construction periods, seriously, of typical methods like as using truck and scaffolds for tunnel maintenance. According to evaluated appropriate design results of space truss frames of numerical examples by using a commercial MIDAS GEN program, it is verified that design parameters such as layered size, cross-sectional size, and steel material of the present space truss frame are determined to depend on characteristics such as lanes or shape of road tunnels.