An efficient genetic algorithm for the design optimization of cold-formed steel portal frame buildings

Phan, Duoc T.; Lim, James B.P.; Tanyimboh, Tiku T.; Sha, Wei

doi:10.12989/scs.2013.15.5.519

Cited by 9 publications

(9 citation statements)

References 11 publications

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“…For example, previous studies indicated that the serviceability criteria can govern the design of CFS frame systems especially in low-seismic regions, e.g. under wind loads [27]. Violation of serviceability requirements (e.g.…”

Section: Introductionmentioning

confidence: 99%

Development of optimum cold-formed steel beams for serviceability and ultimate limit states using Big Bang-Big Crunch optimisation

Mojtabaei

Hajirasouliha

2019

Engineering Structures

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Cold-formed steel (CFS) elements are increasingly used as main structural members in modern construction practice. While flexibility of CFS cross-sectional shape allows achieving higher load carrying capacities by using more efficient shapes, obtaining optimum design solutions can be a challenging task due to end-use constraints and complex behaviour of CFS elements controlled by local, global and distortional buckling modes. This study aims to develop a practical methodology for optimum design of CFS beam sections with maximum flexural strength and minimum deflection under ultimate and serviceability load conditions, respectively, in accordance with Eurocode 3 by taking into account manufacturing and end-use design constrains. Population-based Big Bang Big Crunch Optimisation method is employed to obtain optimum design solutions for twelve different CFS cross-sectional prototypes. To verify the flexural strength and stiffness of the optimum beam sections, detailed nonlinear finite element (FE) models are developed using ABAQUS by considering both material nonlinearity and initial geometrical imperfections. It is shown that the optimised sections based on serviceability limit state (SLS) and ultimate limit state (ULS) can provide, respectively, up to 44% higher effective stiffness and 58% higher bending moment capacity compared to a standard lipped channel beam section with the same plate width and thickness. Using plain channel and folded-flange sections generally leads to the best design solutions for SLS and ULS conditions, respectively. Finally, the results of detailed FE models are used to evaluate the adequacy of EC3 proposed procedures to estimate CFS beam capacity and deflection at ULS and SLS, respectively.

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Section: Introductionmentioning

confidence: 99%

Development of optimum cold-formed steel beams for serviceability and ultimate limit states using Big Bang-Big Crunch optimisation

Mojtabaei

Hajirasouliha

2019

Engineering Structures

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“…To maintain the diversity of population when generation progresses, a niching technique is applied for selection and crossover operators. The details of this process can be found in Phan et al [13].…”

Section: Real-coded Genetic Algorithm (Rc-ga)mentioning

confidence: 99%

“…While optimum design of CFS elements has been extensively investigated in the past, considerably less research has been conducted on optimisation of CFS structural systems. In one of the few studies available in this area, Phan et al [13,14] used Genetic Algorithm (GA) to optimise CFS portal frames with small to medium spans and reported a variation of optimal geometry in terms of pitch and frame spacing for a range of typical column heights. In a follow-up study, it was shown that by taking into account the effects of stressed-skin action (owing to the stiffening effect of roof diaphragm) in the optimisation process, the material cost of the CFS portal frame structural system can be noticeably (up to 53%) reduced [15].…”

Section: Introductionmentioning

confidence: 99%

Coupled element and structural level optimisation framework for cold-formed steel frames

Phan

Mojtabaei

Hajirasouliha

et al. 2020

Journal of Constructional Steel Research

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Optimisation of cold-formed steel (CFS) structures can be challenging due to the complex behaviour of thin-walled CFS sections affected by different buckling modes. In this paper, a coupled framework is presented for element and structural level optimisation of CFS portal frames, under serviceability limit state (SLS) and ultimate limit state (ULS) conditions, using Genetic Algorithm. First, CFS lipped-channel beam sections are optimised with respect to their flexural capacity determined in accordance with the effective width method specified in Eurocode 3 (EC3). The relative dimensions of the cross-section are considered as the main design variables, while the EC3 plate dimensions and slenderness limits and a number of manufacturing and end-use constraints are taken into account in the optimisation process. The results show that the optimum CFS sections exhibit significantly higher (up to 84%) ultimate capacity compared to the standard lipped channel sections with the same plate width and thickness. The structural level optimisation is then carried out to obtain the optimal design solution for a long-span CFS portal frame with knee braces under SLS and ULS conditions. Compared to conventional optimisation using standard cross-sections, it is shown that the proposed coupled framework leads to more cost-effective solutions (up to 20% less structural material) by using the more efficient CFS cross-sectional shapes optimised for generic applications. The results also indicate that optimising the frame geometry and knee brace configuration can noticeably improve the structural performance and reduce the required structural weight, especially when both ULS and SLS conditions are considered.

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“…Depending on the optimization purpose, crosssectional areas of the members and/or nodal coordinates separately or simultaneously can be included as the design variables of the problem. Phan et al (2013), Gholizadeh and Fattahi (2014), Gholizadeh and Poorhoseini (2015), Kaveh and Shokohi (2015), Gholizadeh (2015) and Artar (2016) applied some metaheuristic algorithms for the design optimization problems including the sizing variable only. Although it is possible to obtain better results taking into account both sizing and layout variables, in such a case the optimization problem becomes more complex due to rising number of variables (Hasançebi et al 2009;Tang et al 2005;Miguel et al 2013;Silih et al 2010;Deb, Gulati 2001;Dede, Ayvaz 2015;Bekdaş et al 2015;Aydın, Çakır 2015).…”

Section: Introductionmentioning

confidence: 99%

Weight Minimization of Truss Structures With Sizing and Layout Variables Using Integrated Particle Swarm Optimizer

Mortazavi

Toğan

Nuhoğlu

2017

Journal of Civil Engineering and Management

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This study investigates the performances of the integrated particle swarm optimizer (iPSO) algorithm in the layout and sizing optimization of truss structures. The iPSO enhances the standard PSO algorithm employing both the concept of weighted particle and the improved fly-back method to handle optimization constraints. The performance of the recent algorithm is tested on a series of well-known truss structures weight minimization problems including mixed design search spaces (i.e. with both discrete and continuous variables) over various types of constraints (i.e. nodal displacements, element stresses and buckling criterion). The results demonstrate the validity of the proposed approach in dealing with combined layout and size optimization problems.

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An efficient genetic algorithm for the design optimization of cold-formed steel portal frame buildings

Cited by 9 publications

References 11 publications

Development of optimum cold-formed steel beams for serviceability and ultimate limit states using Big Bang-Big Crunch optimisation

Development of optimum cold-formed steel beams for serviceability and ultimate limit states using Big Bang-Big Crunch optimisation

Coupled element and structural level optimisation framework for cold-formed steel frames

Weight Minimization of Truss Structures With Sizing and Layout Variables Using Integrated Particle Swarm Optimizer

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