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According to the well-known mathematician Leonhard Euler: “Nothing takes place within the universe in which the rule of maximum or minimum does not appear.” The development of optimization algorithms can be traced back to the days of Kepler, Newton, Lagrange and Cauchy and the concept of minimization much earlier to the days of Euclid. However, des...
Citations
... The target functions and constraints in RC frame optimization are essential for establishing the design goals [10] and assuring the frame's structural integrity, safety [89], and sustainability [90]. Following are a few typical goal functions and restrictions applied in this circumstance: Minimization of material usage: Minimising overall material consumption while meeting structural performance standards is one of the key goals of optimizing RC frames [91]. Lowering the quantity of concrete and reinforcing steel needed, can result in more affordable designs. ...
... Topology and structural optimization are deeply rooted from the start of the theory of elasticity (Lagaros, 2018). It was known as the Optimal Layout Theory and its use was not limited to the geometry of the structural unit; it tackled its layout as well. ...
The study presents the integration of Topology Optimization (TO) as a design strategy and Wire Arc Additive Manufacturing (WAAM) as a fabrication strategy. Although TO is well-known in the discipline, a gap in implementing this technique in architectural design due to fabrication limitations remains. In this research, an integrated framework is proposed to obtain a design where both TO and WAAM printing are implemented simultaneously. This framework is divided into five main phases, (1) checking suitability, (2) preprocessing, (3) processing, (4) post-processing, and (5) printing. The framework is then applied to the design of a topology-optimized spiral staircase and studied for fabrication using WAAM metal 3D printing. The results conclude that avoiding the usual standardization of design can be realized by implementing a framework that takes the fabrication strategies into consideration throughout the design process.
... The environmental and economic significance of structural optimization has been more recognized in the recent years [1]. In the context of structural optimization, design of truss systems for minimum weight or cost has been always an active field of research. ...
Benchmarking is an essential part of developing efficient structural optimization techniques. Despite the advent of numerous metaheuristic techniques for solving truss optimization problems, benchmarking new algorithms is often carried out using a selection of classic test examples which are indeed unchallenging for contemporary sophisticated optimization algorithms. Furthermore, the limited optimization results available in the literature on new test examples are usually not accurately comparable. This is typically due to the lack of infromation about the performance of the investigated algorithms and the inconsistencies between the studies in terms of adopted test examples for benchmarking, optimization problem formulation, maximum number of objective function evaluations and other similar issues. Accordingly, there exists a need for developing new standard test suites composed of easily reproducible challenging test examples with rigorous and comparable performance evaluation results of algorithms on these test suites. To this end, the present work aims to propose a new baseline for benchmarking structural optimization algorithms, using a set of challenging sizing and shape optimization problems of truss structures selected from the international student competition in structural optimization (ISCSO) instances. The most recent six structural optimization examples from the ISCSO are tackled using a representative metaheuristic structural optimization algorithm. The statistical results of all the optimization runs using the proposed benchmarking suite are provided to pave the way for more rigorous benchmarking of structural optimization algorithms.
... To achieve the goals agreed in the Paris climate agreement, extensive restructuring of the economy is required worldwide. The construction sector carries a great responsibility since it is a huge consumer of materialressources globally [10,11]. Cement production in particular is responsible for around 8 % of anthropogenic CO 2 emissions, although concrete does not have a higher CO 2 footprint than other building materials [12]. ...
One of the main challenges in concrete construction at present is the reduction of CO2 emissions. To achieve this, both academia and industry are testing innovative methods, developing CO2-reduced materials, and implementing design principles. CO2-reduced materials are being developed and construction principles are being implemented. In addition to the development of new resource-saving construction materials, innovative manufacturing processes such as additive manufacturing are being tested to use the materials only where they are needed. One promising approach is the use of textile reinforced concrete, which uses woven glass, basalt, aramid or carbon fibres that have a much higher tensile strength than conventional structural steel. As a chemically inert material, carbon fibres offer the additional advantage of being insensitive to corrosion and are therefore particularly suitable for the realisation of durable, material-saving high-performance concrete elements. The extrusion process is an innovative method for implementing new construction concepts from carbon reinforced concrete. In this process, solid to viscous materials are transported through an extruder and pressed through a shaping mouthpiece. This enables the efficient production of precise linear components without the need for formwork. Initial approaches to integrating flexibly impregnated textiles in a laboratory extruder were already carried out in 2012 at the Institute of Building Materials Research at RWTH Aachen University (ibac). However, for the implementation of high-performance textile reinforced concrete components with subsequent longitudinal and transversal shaping with a laboratory extruder, scientifc fundamentals and methods are lacking. In this work, the state of the art of textile reinforced concrete, concrete extrusion and form optimised constructions is presented first. It is followed by four papers in which the scientific research and methods developed in the context of this work are presented. Chapter 2 presents the basic principles for the development of an innovative mouthpiece that allows the integration of arbitrarily stiff impregnated textiles in the concrete extrusion process. Chapter 3 describes the development of a test method used to accurately describe concrete mixtures prior to actual extrusion in order to predict defect-free extrusion in LabMorTex. In Chapter 4, the shaping behaviour of the (un)reinforced, microfiber- and textile reinforced concrete after extrusion is investigated. The aim of the investigations is to identify the technical limits of longitudinal and transverse shaping for the implementation of material-minimised structures. Chapter 5 describes the design and Chapter 6 the implementation of an innovative wall / slab element assembled from extruded textile reinforced components. In addition, the slab element is compared with an equivalent reinforced concrete system of the same dimensions and the same flexural strength in terms of sustainability and structural design. The aim of the study is to implement the findings obtained in Chapters 2–4 in an exemplary building component.Finally, chapter 6.3 presents and discusses the results of the durability study of the extruded concrete.
... The construction sector plays key part in the world's economy because it consumes approximately 40% of global energy, accounts for approximately 10% of the global gross domestic product (GDP) and employs millions of people (Lagaros, 2018). The US Geological Survey research institute (USGS, 2017, apud Lagaros, 2018, p. 1752 has recently assessed cement consumption worldwide and reported cement production increase from 536 to 4200 million tons, between 1967 and 2016. ...
The aim of the current study is to apply multi-objective optimization to precast slab designs to help minimizing the cost, execution time and amount of manpower required at construction sites. Design variables comprised filler element thickness, distance between rib axes, and steel area, whereas variables associated with manpower encompassed number of carpenters, assemblers and masons. Restrictions concerned design equations at ultimate limit state and verification equations at serviceability limit state. Moreover, there were restrictions for the minimum and maximum amounts of manpower. Four optimization cases were analyzed. Cost was the objective function in case 1; execution time was minimized in case 2; and multi-objective optimization was applied in cases 3 and 4, whose objective functions were cost, execution time and amount of manpower. Two projects with different slab spans were investigated in each case. It is worth highlighting results observed in Case 4, according to which, lower cost tended to correspond to longer execution time and to smaller amount of manpower. Thus, multi-objective optimization application provides a larger set of optimal solutions for decision makers, due to conflict among objective functions.
... The process of reducing the volume of a structure to reduce its cost Sarma and Adeli (2002), Sirca and Adeli (2005), Sarma and Adeli (2000) and Liu and Neghabat (1972) Structural performance development Improvements in structural properties are made to adapt to functional requirements Lagaros (2014), , Yang et al. (2010) and Systems (2005) Environmental impact minimization Optimization of structure to minimize its impact on the environment, including emissions of gases, structure in water and material impact on aquatic species Lagaros (2018), Lim andPark (2009), de Medeiros andKripka (2014) and Van Cauteren et al. (2022) Multi-objective Process of multiple objectives from all those mentioned above Al-Saadi et al. (2021), Marler and Arora (2004), Zavala et al. (2014a) and Quaglia et al. (2014) (Oleinik and Yurgaytis, 2017), design, geotechnical engineering (Hajihassani et al., 2018), transportation (Sun et al., 2015) and mechanics, has received considerable attention. ...
Purpose
The purpose of this article is to analyze the optimization process in depth, elaborating on the components of the entire process and the techniques used. Researchers have been drawn to the expanding trend of optimization since the turn of the century. The rate of research can be used to measure the progress and increase of this optimization procedure. This study is phenomenal to understand the optimization process and different algorithms in addition to their application by keeping in mind the current computational power that has increased the implementation for several engineering applications.
Design/methodology/approach
Two-dimensional analysis has been carried out for the optimization process and its approaches to addressing optimization problems, i.e. computational power has increased the implementation. The first section focuses on a thorough examination of the optimization process, its objectives and the development of processes. Second, techniques of the optimization process have been evaluated, as well as some new ones that have emerged to overcome the above-mentioned problems.
Findings
This paper provided detailed knowledge of optimization, several approaches and their applications in civil engineering, i.e. structural, geotechnical, hydraulic, transportation and many more. This research provided tremendous emerging techniques, where the lack of exploratory studies is to be approached soon.
Originality/value
Optimization processes have been studied for a very long time, in engineering, but the current computational power has increased the implementation for several engineering applications. Besides that, different techniques and their prediction modes often require high computational strength, such parameters can be mitigated with the use of different techniques to reduce computational cost and increase accuracy.
... Maximization of material usage efficiency through minimization of the structure weight is a common objective function. In this context, structural optimization may also contribute to reducing environmental impacts (Lagaros 2018). ...
Discrete sizing and topology optimization of truss structures subject to stress and displacement constraints has been formulated as a Mixed-Integer Linear Programming (MILP) problem. The computation time to solve a MILP problem to global optimality via a branch-and-cut solver highly depends on the problem size, the choice of design variables, and the quality of optimization constraint formulations. This paper presents a new formulation for discrete sizing and topology optimization of truss structures, which is benchmarked against two well-known existing formulations. Benchmarking is carried out through case studies to evaluate the influence of the number of structural members, candidate cross sections, load cases, and design constraints (e.g., stress and displacement limits) on computational performance. Results show that one of the existing formulations performs significantly worse than all other formulations. In most cases, the new formulation proposed in this work performs best to obtain near-optimal solutions and verify global optimality in the shortest computation time.
... In addition, in the beam-column connection, the strength of the connection between the inclined column, the beam, and the slab may be significantly reduced compared to the strength of the standardized beam-column connection. In case of an atypical skyscraper structure system, the amount of welding can be further increased depending on the shape condition, and the risk of brittle fracture is high [51].Therefore, it is necessary to develop joint details that can minimize the amount of welding and respond appropriately to irregular shapes. The joint detail development can be developed using the current BIM Tool (REVIT, TEKLA), and the developed joint detail can be reviewed for structural performance through FEM analysis (Ansys, Abaqus). ...
Contemporary atypical skyscrapers in United Arab Emirates became the landmarks of the city and secured the urban competitiveness via innovative building design. These contemporary skyscrapers use non-linear geometry of structural frames, it is impossible to design these structures with conventional design methods. The objective of this paper is to examine the unit technologies for structural design of an atypical skyscraper and propose an optimal structural design process. As a methodology, the status of atypical skyscraper optimization technologies is analyzed, the status of data exchange among structural analysis programs, BIM software and FEM analysis programs are examined, and the case studies of some landmark buildings in United Arab Emirates designed by well known companies such as SOM, AECOM, and Salama Structural Engineers are explored. The result has shown that the unit technologies for optimizing atypical skyscrapers can follow four phases: Concept Design Phase, Schematic Design Phase, Design Development Phase and Construction Documentation Phase.
... demand will grow, reaching four times more than in 1990. Furthermore, cement production is closely linked to demand for steel; in 2016, Asia and Oceania alone required 1000 million tons of steel [16]. These data, translated in terms of environmental impact, mean producing disastrous consequences on the environment. ...
In the world of structural design, in most cases, there is a need to control the shape of structural elements and—at the same time—the performance that each one can achieve. With the evolution of structural analysis tools, nowadays it is possible not only to have an immediate investigation of the structure’s performance, but also to search for the best shape by imposing geometric constraints. The aim of this paper is to present an innovative methodology called the performative structural design optimization (PSDO) method, based on the use of algorithm-aided design (AAD). The proposed approach deals with an emptied voided beam; starting from the parameterization of a large-span beam, the search method for the most performing shape is accomplished by multi-objective evolutionary algorithms (MOEAs). The obtained results are characterized by a double optimization: the structure achieved by the hypervolume estimation algorithm for multi-objective optimization (HypE Reduction) (OCTOPUS) represents the starting shape for the application of form-finding, giving so the possibility to obtain different feasible solutions from a single study and to choose the best one in terms of structural behavior.
... Structural sizing optimization typically aims at detecting the optimum cross-sectional geometric properties of the structural components that minimize the cost (or material weight/volume) of a structure subject to behavioral constraints (controlling mainly stresses and displacements or drifts) as imposed by design codes. Relevant optimization formulations refer to the weight minimization problem of truss and frame structures [1][2][3][4][5][6][7], the life-cycle cost optimization problem [8], the problem of performance-based structural design optimization [9][10][11], the environmentally driven structural design optimization problem [12,13], etc. ...
... Although the basic concept of cascading assumes the utilization of a different optimization algorithm at each cascade stage, the case of invoking the same optimizer at more than one (or even at all) cascade stages should not be excluded. A number of cascading variations have been successfully implemented in structural optimization applications: various gradient-based optimizers were utilized at the cascade stages in [17][18][19][20]; a gradient-based optimizer and a response surface approach were integrated in the framework of a cascade procedure in [21]; the same evolutionary optimizer was employed at all cascade stages in [15,22]; both gradient-based and evolutionary optimizers were applied one after the other in [23]; cascading was implemented also in a general-purpose design optimization platform [24] and applied to real-world structural design optimization problems [12]. ...
In structural sizing optimization problems, the number of design variables typically used is relatively small. The aim of this work is to facilitate the use of large numbers of design variables in such problems, in order to enrich the set of available design options and offer the potential of achieving lower-cost optimal designs. For this purpose, the concept of cascading is employed, which allows an optimization problem to be tackled in a number of successive autonomous optimization stages. In this context, several design variable configurations are constructed, in order to utilize a different configuration at each cascade sizing optimization stage. Each new cascade stage is coupled with the previous one by initializing the new stage using the finally attained optimum design of the previous one. The first optimization stages of the cascade procedure make use of the coarsest configurations with small numbers of design variables and serve the purpose of basic design space exploration. The last stages exploit finer configurations with larger numbers of design variables and aim at fine-tuning the achieved optimal solution. The effectiveness of this sizing optimization approach is assessed using real-world aerospace and civil engineering design problems. Based on the numerical results reported herein, the proposed cascade optimization approach proves to be an effective tool for handling large numbers of design variables and the corresponding extensive design spaces in the framework of structural sizing optimization applications.
