Minimum cost design of RC beams using DCOC Part I: Beams with freely-varying cross-sections

Adamu, Abebaw Yirga; Karihaloo, Bhushan Lal

doi:10.1007/bf01743718

Cited by 15 publications

(6 citation statements)

References 23 publications

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“…The equations of implicit constraints for the U-shaped girder are based on AASHTO LRFD Bridge design specifications [7,[51][52][53]. They consist of stresses, deflection, ultimate strength, cracking moment, and shear strength [34,38] as follows:…”

Section: Implicit Constraintsmentioning

confidence: 99%

“…By optimal design, we mean the structure which is cost-effective without disturbing the practical purposes of the structure under attention [33]. The total expense of the structure is mostly the summation of the cost of its distinct component materials, which include concrete, steel reinforcement, and prestressing strands in the case of a prestressed girder [27,34]. The computation of prestressing losses also plays a crucial role in optimization problems, especially in the design of PC girder bridges.…”

Section: Introductionmentioning

confidence: 99%

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Cost Optimization of Prestressed U-Shaped Simply Supported Girder Using Box Complex Method

et al. 2023

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The use of U-shaped girders has become increasingly popular in advanced projects such as metro rail systems due to their ability to provide greater vertical clearance beneath bridges. These girders, characterized by two webs and a bottom flange, contribute essential longitudinal stiffness and strength to the overall structure while effectively countering torsional forces in curved bridges. However, the design and construction of U-shaped girders present challenges, including their relatively higher self-weight compared to other girder types. Consequently, cost optimization has become a crucial focus in structural design studies. This research aims to develop an optimization model for prestressed U-shaped girders using the AASHTO LRFD bridge design specifications. The model is based on the Box complex method, with necessary modifications and improvements to achieve an optimal design. The objective is to minimize the total cost of materials, including concrete, steel reinforcement, and prestressing strands, while satisfying explicit and implicit design constraints. To facilitate the analysis, design, and optimization processes, a program is developed using Visual Studio 2010 and implemented in Visual Basic (VB.NET). The program incorporates separate subroutines for analysis, design, and optimization of the prestressed U-shaped girder, which are integrated to produce the desired results. When running the program, the optimization process required 229 iterations to converge to the optimal cost function value. The results demonstrate that the developed algorithm efficiently explores economically and structurally effective solutions, resulting in cost savings compared to the initial design. The convergence rate of the moment capacity constraint is identified as a key factor in achieving the optimal design. This research makes a significant contribution to the field of civil engineering by applying the classical Box complex method to the optimization of girders, an area where its utilization has been limited. Furthermore, this study specifically addresses the optimization of prestressed U-shaped girders in metro rail projects, where they serve as both the deck and support structure for train loading. By employing the Box complex method, this research aims to fill the research gap and provide valuable insights into the optimization of U-shaped girders. This approach offers a fresh perspective on designing these girders, considering their unique role in supporting metro rail loads. By leveraging the benefits of the Box complex method, researchers can explore new possibilities and uncover optimal design solutions for U-shaped girders in metro rail applications.

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Section: Implicit Constraintsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cost Optimization of Prestressed U-Shaped Simply Supported Girder Using Box Complex Method

et al. 2023

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“…0 0 The minimum cost design problem of an l~C frame structure including the constraints and bounds may be mathematically stated using the augmented Lagrangian as follows: (3), (23), (24) and (25) (27) and (28) due to the inclusion 0z 2 of selfweight in the equilibrium equation of the real system. As discussed in the works of Zhou and Rozvany (1992), and Adamu and Karihaloo (1994a), {a r } is a scaled adjoint displacement vector given by {~r]T = ~{~]T.…”

Section: Problem Formulation Using An Augmented Lagrangianmentioning

confidence: 99%

“…For the satisfaction of the compatibility condition of the adjoint system, the adjoint initial displacements may be obtained from (23), (24) or (25). In the notation of Adamu and Karihaloo (1994a) …”

Section: Problem Formulation Using An Augmented Lagrangianmentioning

confidence: 99%

Minimum cost design of RC frames using the DCOC method Part I: Columns under uniaxial bending actions

Adamu

Karihaloo

1995

Structural Optimization

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A b s t r a c tThe paper solves the minimum-cost design problem of RC plane frames. The cost to be minimized includes those of concrete, reinforcing steel and formwork, whereas the design constraints include limits on maximum deflection at a specified node, on bending and shear strengths of beams and on combined axial and bending strength of columns, in accordance with the limit state design (LSD) requirements. The algorithms developed in this work can handle columns under uniaxial bending actions. In the companion paper the numerical procedure is generalized to include columns subjected to biaxial bending. On the basis of discretized continuum-type optimality criteria (DCOC), the design problem is systematically formulated, followed by explicit mathematical derivation of optimality criteria upon which iterative procedures are developed for the solution of design problems when the design variables are the cross-sectional parameters and steel ratios. For practical reasons, the cross-sectional parameters are chosen to be either uniform per member or uniform for several members at a given floor level. The procedure is illustrated on several test examples. It is shown that the DCOC-based methods are particularly efficient for the design of large RC frames.

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“…Some "RC beam optimization" publications that are already available dealing with minimization of cost and weight of RC beams using Genetic Algorithms (GA) [1,4,6] and Discretized Continuum-type Optimality Criteria (DCOC) [2,3], using Artificial Neural Network (ANN) [5], Teaching-Learning-based Optimization (TLBO) [10], Random Search Technique (RST) [8], and analytical approach [11], to cite a few.…”

Section: Introductionmentioning

confidence: 99%

Reinforced Concrete (RC) beam design application for android based on SNI 2847:2013 (CEMA)

2019

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In Indonesia RC structures are widely used for high rise, low rise, shop offices, as well as residential buildings. In February 2018, the first author introduced an RC beam design application for Android [12] for two options. Option one is for calculating nominal moment (Mn) and nominal shear force (Vn) of the section when the beam dimensions (b, h) and reinforcements are known; option two is to calculate the number of reinforcements for Mn and Vn when the dimensions (b, h) are known. In this paper, the first author added option three, namely the optimization for the design of RC beams when the internal forces are known and the application calculates the most optimal dimensions (b, h) and reinforcements. The application developed is named Civil Engineering Mobile Application for Concrete Beams (CEMA) and is called C2. In CEMA the user can follow the step by step calculation and the results of the calculation are stored in a database. For option three of CEMA (optimization of RC beam sections), the application was validated by another method called Teaching-Learning-based Optimization (TLBO) method [10]. It is believed that CEMA which is based on SNI 2847:2013 can be useful for Indonesian structural engineers designing and supervising actual construction RC buildings.

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Minimum cost design of RC beams using DCOC Part I: Beams with freely-varying cross-sections

Cited by 15 publications

References 23 publications

Cost Optimization of Prestressed U-Shaped Simply Supported Girder Using Box Complex Method

Cost Optimization of Prestressed U-Shaped Simply Supported Girder Using Box Complex Method

Minimum cost design of RC frames using the DCOC method Part I: Columns under uniaxial bending actions

Reinforced Concrete (RC) beam design application for android based on SNI 2847:2013 (CEMA)

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