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Cost optimization of reinforced concrete section according to flexural cracking
Primož Jelušič, 2022, original scientific article

Abstract: A series of distributed flexural cracks develop in reinforced concrete flexural elements under the working load. The control of cracking in reinforced concrete is an important issue that must be considered in the design of reinforced concrete structures. Crack width and spacing are influenced by several factors, including the steel percentage, its distribution in the concrete crosssection, the concrete cover, and the concrete properties. In practice, however, a compromise must be made between cracking, durability, and ease of construction and cost. This study presents the optimal design of a reinforced concrete cross-section, using the optimization method of mixed-integer nonlinear programming (MINLP) and the Eurocode standard. The MINLP optimization model OPTCON was developed for this purpose. The model contains the objective function of the material cost considering the crack width requirements. The crack width requirements can be satisfied by direct calculation or by limiting the bar spacing. Due to the different crack width requirements, two different economic designs of reinforced concrete sections were proposed. The case study presented in this study demonstrates the value of the presented optimization approach. A direct comparison between different methods for modelling cracking in reinforced concrete cross-sections, which has not been done before, is also presented.
Keywords: crack width, cost optimization, optimal design, mixed-integer non-linear programming
Published in DKUM: 13.03.2025; Views: 0; Downloads: 1
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A practical method for the optimal design of continuous footing using ant-colony optimization
Boonchai Ukritchon, Suraparb Keawsawasvong, 2016, original scientific article

Abstract: The objective of this paper is to present a practical method for the optimal design of a continuous footing subjected to vertical and horizontal loads. The design problem of finding the optimal size of footing as well as the minimum steel reinforcement is formulated in a nonlinear minimization form. The continuous footing is subjected to the vertical and horizontal loads acting on the top of the column. There are four design variables in the design problem, i.e., the width of the footing, the thickness of the footing, the soil-embedment depth, and the amount of steel reinforcement. The required geotechnical constraints include the bearing capacity, overturning, as well as global sliding and local sliding at the footing corners. Short-term stability and long-term stability are considered simultaneously in the same formulation. The structural constraints are enforced to control the shear force and bending moment within the section resistance. The formulation of the problem’s constraints leads to the nonlinear programming, whose objective function is to minimize the total cost of the footing material, including the concrete and steel reinforcement. The optimal solution is solved using the ant-colony optimization algorithm MIDACO. The proposed optimization method is demonstrated through the actual design of the footing for supporting a large machine moving on rails.
Keywords: optimal design, footing, stability, nonlinear programming, ant-colony optimization
Published in DKUM: 18.06.2018; Views: 1480; Downloads: 94
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Parameterization based shape optimization : theory and practical implementation aspects
Marko Kegl, 2005, original scientific article

Abstract: This paper presents an approach to parameterization based shape optimization of statically loaded elastic structures. The shape parameterization is based on the design element technique and a rational Bezicr body is used to serve as the design element. Practical implementation issues related to the introduction of design variables are discussed briefly. The design sensitivity calculation is based on the discrete approach. The proposed solution process layout is based on a stand-alone optimization program which makes use of compatiblc analysis programs called simulators. For illustrationpurpose an example problem containing shape and sizing design variables is formulated and solved. The range of use of the proposed approachis illustrated with three further examples.
Keywords: mechanics, structure parameterization, shape optimal design, finite element mesh, body parameterization, design element, Bezier body
Published in DKUM: 01.06.2012; Views: 2028; Downloads: 78
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