• Structural Engineering and Mechanics
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• 제70권1호
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• pp.81-96
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• 2019

In this paper, a hybrid uncertain model is applied to system reliability based design optimization (RBDO) of trusses. All random variables are described by random distributions but some key distribution parameters of them which lack information are defined by variation intervals. For system RBDO of trusses, the first order reliability method, as well as monotonicity analysis and the branch and bound method, are utilized to determine the system failure probability; and Improved (${\mu}+{\lambda}$) constrained differential evolution (ICDE) is employed for the optimization process. System reliability assessment of several numerical examples and system RBDO of different truss structures are proposed to verify our results. Moreover, the effect of different classes of interval distribution parameters on the optimum weight of the structure and the reliability index are also investigated. The results indicate that the weight of the structure is increased by increasing the uncertainty level. Moreover, it is shown that for a certain random variable, the optimum weight is more increased by the translation interval parameters than the rotation ones.

• 전산구조공학
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• 제27권4호
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• pp.62-67
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• 2014

• 한국전산구조공학회논문집
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• 제31권1호
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• pp.1-8
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• 2018

본 연구의 목적은 강성 개폐식 대공간 건축물의 비정형 입체트러스를 파라메트릭 기법을 적용하여 모델링을 구현하는데 있다. 개폐식 대공간 건축물은 비선형성 형상을 모델링하거나 다수의 모델을 대안별로 생성, 해석, 검토하는 과정에 많은 시간과 기술이 소요되는 것이 현 실정이다. 이러한 문제점을 해결하기 위해서 첫째로, 개발에 사용된 파라메트릭 모델링 전산도구를 소개하고, 강성 개폐식 대공간 건축물의 비정형 입체트러스를 분석하며, 개발한 입체트러스의 파라메트릭 컴포넌트로 모델링을 구현하게 된다. 따라서 지붕이 개폐되는 방식으로 구분한 입체 트러스 종류의 모델링을 구현해 낼 수 있는 컴포넌트를 형상이나 기능에 따른 각각 대안별로 개발하여 효율적인 개폐식 지붕의 모델링을 가능하게 하는 것이 추후 연구사항이다.

• 한국강구조학회 논문집
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• 제24권6호
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• pp.637-645
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• 2012

슬래브와 트러스 보의 합성효과를 고려한 합성트러스의 경우 단순히 고정하중으로 취급되던 슬래브를 구조체로서 활용할 수 있으므로 구조재료를 매우 효과적으로 활용할 수 있게 되고 구조체의 강성이 증가하게 되므로 장스팬 설계의 중요 변수인 사용성 측면에서도 상당한 이점을 확보할 수 있게 된다. 이와 더불어 슬래브 하부에 다양한 설비 시설을 위한 공간이 확보되므로 보의 춤이 깊어지는데 대한 단점을 상당부분 상쇄할 수 있게 된다. 본 연구는 합성 트러스 시스템을 개발함에 있어 상하현재를 600MPa급 고강도강을 사용하여 실험과 수치해석을 통해 스터드 커넥터의 유 무에 따른 합성 트러스의 역학적 거동 특성을 평가하는 것을 목적으로 한다. 또한 상하현재로 일반강재를 사용한 연구결과와 비교하였다. 그 결과 고강도강으로 T형강을 사용한 경우는 일반강재를 T형강으로 사용한 경우보다 구조성능에서 더욱 효율적임을 알 수 있었다.

• 한국강구조학회 논문집
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• 제22권6호
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• pp.599-608
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• 2010

트러스의 상현재와 콘크리트 슬래브가 합성 거동하는 합성 트러스는 장스팬에 경제적인 구조시스템임에도 불구하고 현재 국내에서 설계되는 대부분의 트러스 보는 바닥슬래브와의 합성효과를 전혀 고려하지 않고 설계되고 있다. 슬래브와 트러스 보의 합성효과를 고려할 경우에는 단순히 고정하중으로 취급되던 슬래브를 구조체로서 활용할 수 있으므로 구조 재료를 매우 효율적으로 활용할 수 있게 되고 구조체의 강성이 증가하게 되므로 장스팬 설계의 중요 변수인 사용성 측면에서도 상당한 이점을 확보할 수 있게 된다. 이와 더불어 슬래브 하부에 다양한 설비 시설을 위한 공간이 확보되므로 보의 춤이 깊어지는데 대한 단점을 상당부분 상쇄할 수 있게 된다. 본 연구는 합성 트러스 시스템을 개발함에 있어 국내 현실을 충분히 반영하여 국내 설계 및 시공 현장에서 바로 적용하기 위한 초기단계의 연구로서 실험과 수치해석을 통해 스터드 커넥터의 유 무에 따른 합성 트러스의 역학적 거동 특성을 평가하기 위한 것에 목적을 두고 있다.

• Structural Engineering and Mechanics
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• 제64권5호
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• pp.671-681
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• 2017

This study investigates the structural performance of 3D steel pipe rack suspended scaffolding systems. For the purpose, a standard full scale 3D steel pipe rack suspended scaffolding system considering two frames, two plane trusses, purlins and wooden floor is constructed in the laboratory. A developed load transmission system was placed in these experimental systems to distribute single loads to the center of a specific area in a step-by-step manner using a load jack. After each load increment, the displacements are measured by means of linear variable differential transducers placed in several critical points of the system. The tests are repeated for five different system conditions to determine the structural performance. The means of system conditions is the numbers of the tie bars which are used to connect plane trusses under level. Finite elements models of the 3D steel pipe rack suspended scaffolding systems considering different systems conditions are constituted using SAP2000 software to support the experimental tests and to use the models in future studies. Each of models including load transmission platform is analyzed under a single loading and the displacements are obtained. In addition, to calibrate the numerical models some uncertain parameters such as elasticity modulus of wooden floor and connection rigidity of purlins to plane trusses are assessed experimentally. The results of this work demonstrate that when increasing numbers of tie bars the displacement values are decreased. Also the results obtained from developed numerical models have harmony with those of experimental. In addition, the scaffolding system with two tie bars at the beginning and at the end of the plane truss has the optimum structural performance compared the results obtained for other scaffolding system conditions.

• Steel and Composite Structures
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• 제1권1호
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• pp.17-32
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• 2001

The Rosette-joining system is a completely new press-joining method for cold-formed steel structures. One Rosette-joint has a shear capacity equal to that of approximately four screws or rivets. The Rosette thin-walled steel truss system presents a new fully integrated prefabricated alternative to light-weight roof truss structures. The trusses are built up on special industrial production lines from modified top hat sections used as top and bottom chords and channel sections used as webs which are joined together with the Rosette press-joining technique to form a completed structure easy to transport and install. A single web section is used when sufficient but can be strengthened by double-nesting two separate sections or by using two lateral profiles where greater compressive axial forces are met. An individual joint in the truss can be strengthened by introducing a hollow bolt into the joint hole. The bolt gives the connection capacity a boost of approximately 20%. A series of laboratory tests have been carried out in order to verify the Rosette truss system in practice. In addition to compression tests on individual sections of different lengths, tests have also been done on small structural assemblies and on actual full-scale trusses of a span of 10 metres. Design calculations have been performed on selected roof truss geometries based on the test results, FE-analysis and on the Eurocode 3 and U.S.(AISI) design codes.

• 한국공간구조학회지
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• 제17권3호
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• pp.4-8
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• 2017

• Steel and Composite Structures
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• 제2권3호
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• pp.209-222
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• 2002

This paper describes the buckling phenomenon of a tubular truss with unsupported length through a full-scale test and presents a practical computational method for the design of the trusses allowing for the contribution of torsional stiffness against buckling, of which the effect has never been considered previously by others. The current practice for the design of a planar truss has largely been based on the linear elastic approach which cannot allow for the contribution of torsional stiffness and tension members in a structural system against buckling. The over-simplified analytical technique is unable to provide a realistic and an economical design to a structure. In this paper the stability theory is applied to the second-order analysis and design of the structural form, with detailed allowance for the instability and second-order effects in compliance with design code requirements. Finally, the paper demonstrates the application of the proposed method to the stability design of a commonly adopted truss system used in support of glass panels in which lateral bracing members are highly undesirable for economical and aesthetic reasons.

• Structural Engineering and Mechanics
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• 제52권1호
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• pp.149-172
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• 2014

Four algorithms for damage detection of trusses are presented in this paper. These approaches can detect damage by using both complete and incomplete measurements. The suggested methods are based on the minimization of the difference between the measured and analytical static responses of structures. A non-linear constrained optimization problem is established to estimate the severity and location of damage. To reach the responses, the successive quadratic method is used. Based on the objective function, the stiffness matrix of the truss should be estimated and inverted in the optimization procedure. The differences of the proposed techniques are rooted in the strategy utilized for inverting the stiffness matrix of the damaged structure. Additionally, for separating the probable damaged members, a new formulation is proposed. This scheme is employed prior to the outset of the optimization process. Furthermore, a new tactic is presented to select the appropriate load pattern. To investigate the robustness and efficiency of the authors' method, several numerical tests are performed. Moreover, Monte Carlo simulation is carried out to assess the effect of noisy measurements on the estimated parameters.