Minimum Cost Design Research Articles

Optimization for the design of reinforced concrete corner combined footings

This paper presents the simplified and generalized equations to estimate the optimal design based in the concept of minimum cost for the reinforced concrete corner combined footings under axial load and biaxial moments in each column that considers the linear pressure of the soil acting on the footing contact surface. This work is presented in two stages: in the first stage the minimum contact surface on the footing is obtained, and in the second stage the minimum cost for design is obtained. The formulation was developed under the condition that the derivative of the moment is the shear force. Four examples are shown to obtain the minimum cost for the complete design. The solution is obtained with the help of Maple-15 software that solves these types of problems. The results show that there is no direct relationship between the optimal area and the minimum cost design.

Product platform design for minimum cost in mass customization manufacturing environment

Abstract Nowadays manufacturers are facing several challenges to compete in the marketplace. One of the main challenges can be described by the need to offer a range of products and categories in addition to shortening the time during which the product is brought to the customer while maintaining low costs to achieve maximum profitability. Several approaches emerged during the past couple of decades that enabled designers and manufacturers to offer the product variety within a product family on one hand and allowing flexibility and responsiveness at the manufacturer’s side on the other hand. This study addressed the problem of product platform design with the objective of minimizing the manufacturing costs incurred in the platform manufacturing phase and the mass customization phase. A genetic algorithm model that minimizes the total manufacturing cost is developed where optimum product platform design is determined. The developed model is used to study the effect of demand proportion of different product variants within a product family on the platform design and the total manufacturing cost.

Application of evolutionary algorithms to design economic flat slab buildings based on the intended function

Numerous studies revealed optimization techniques' applicability in minimizing the costs of reinforced concrete buildings. However, the existing literature has narrowly focused on optimizing buildings with a single function, such as residential or office buildings, hindering the generalization of the results. This paper aims to bridge the gap between optimization and structural engineering by obtaining the minimum-cost design of flat slab buildings with different intended functions. In this context, the optimal designs of 120 alternatives were obtained, considering various spans (4–8 m), live loads (2–10 kPa), and concrete compressive strength (25–40 MPa). The optimization was executed using the evolutionary algorithm provided in Microsoft Excel’s Solver tool. The optimization model permits the utilization of drop panels to resist punching stresses developed from the slab-column interaction. The objective function is the cost of materials and labor involved in constructing floors and columns. The decision variables are the floor dimensions and column configurations in dimensions and reinforcement. The structural constraints were applied per the Egyptian design code (ECP203-2020). Eventually, guidelines were developed to help the designers choose the economic floor system and quantities of materials based on the building's intended function.

Mathematical Modeling for the Optimal Cost Design of Circular Isolated Footings with Eccentric Column

This article shows a model for the design of circular isolated footings and the column placed anywhere in the footing under minimum cost criteria. Some designs for obtaining the diameter, effective depth, and steel areas of the footing under biaxial bending assume the maximum and uniform pressure at the bottom of the footing supported on elastic soils. All these works consider the column placed at the center of the footing. Three numerical problems are given (each problem presents four variants) to determine the lowest cost to design the circular footings under biaxial bending. Problem 1: Column without eccentricity. Problem 2: Column with eccentricity in the direction of the X axis of one quarter of the diameter of the footing. Problem 3: Column placed at the end furthest from the center of the footing on the X axis. The results are verified by the balance of moments, one-way shear or shear and two-way shear or punching. The new model shows a saving of 17.92% in the contact area with soil and of 31.15% in cost compared to the model proposed by other authors. In this way, the proposed minimum cost design model for circular footings will be of great help for the design when the column is placed on the center or edge of the footing.

Economically optimized design point of high-field stellarator power-plant

High temperature superconductors (HTSs) expand the design space of stellarator power-plants (PPs) toward high magnetic fields B, enabling compact major radii R. The present paper scans the space of B, R and other design parameters, finding solutions that are promising from a physics and engineering standpoint, while minimizing the capital cost of the PP and the levelized cost of fusion electricity. Similarly, it identifies minimum-cost design points for next-step burning plasma stellarator experiments of fusion gain 1<Q<10 . The study assumes advanced stellarator configurations of reduced aspect ratio, heated by neutral beam injection. Plasma-facing, flowing liquid metal (LM) walls protect it from high heat and neutron fluxes. The study relies on analytical first-principle calculations, and established zero-dimensional (0D) empirical scaling laws. Power flows are illustrated by Sankey diagrams. Plasma operating contours are used to determine the reactor’s start-up path. Sensitivity analyses are conducted to identify the most critical reactor parameters within physics, engineering and costing, quantifying their influence on the economics of the PPs. Such 0D study suggests that the assumed next generation HTS, flowing LM walls, and advances in compact plasma configurations could lead to an ignited stellarator PP of aspect ratio A∼4 , R⩽4 m, B > 9 T, and normalized plasma pressure β∼5% which would minimize both the cost of electricity and capital cost while achieving a net electric power of about 1 GW.

A Minimum Cost Design Approach for Steel Frames Based on a Parallelized Firefly Algorithm and Parameter Control

In this work, the applicability of a Firefly Algorithm (FA) to the real problem of the minimum cost of a detailed design for steel frames is studied. To reduce the calculation time, which is a common problem of meta-heuristic algorithms when they are used to solve real design cases, and to better suit the characteristics of the algorithm, a parallel migration strategy has been implemented and tested. As it is well known that the performance of any metaheuristic algorithm depends on the chosen value of its parameters, an extensive sensitivity analysis has been carried out. This not only serves to improve performance but also provides information on how it depends on the values of these parameters. With the information obtained from this analysis, and in order to achieve the robust behavior of the algorithm, a parameter control strategy has also been implemented and tested. Finally, a study demonstrating the close dependence between one of the parameters and the number of variables considered in the examples has been carried out. As a result of this final study, a simple expression is proposed that provides the minimum necessary population based on the number of variables in the problem.

Ammonia stripping and scrubbing followed by nitrification and denitrification saves costs for manure treatment based on a calibrated model approach

Resource-efficient nitrogen management is of high environmental and economic interest, and manure represents the major nutrient flow in livestock-intensive regions. Ammonia stripping/scrubbing (SS) is an appealing nitrogen recovery route from manure, yet its real-life implementation has been limited thus far. In nutrient surplus regions like Flanders, treatment of the liquid fraction (LF) of (co–)digested manure typically consists of nitrification/denitrification (NDN) removing most N as nitrogen gas. Integrating SS before NDN in existing plants would expand treatment capacity and recover N while maintaining low N effluent values, yet cost estimations of this novel approach after process optimisation are not yet available. A programming model was developed and calibrated to minimise the treatment costs of this approach and find the balance between N recovery versus N removal. Four crucial operational parameters (CO2 stripping time, NH3 stripping time, temperature and NaOH addition) were optimised for 18 scenarios which were different in terms of technical set-up, influent characteristics and scrubber acid. The model shows that SS before NDN can decrease the costs by 1 to 56% under optimal conditions compared to treatment with NDN only, with 1 to 8% reduction for the LF of manure (22–29% recovered of N treated), and 11 to 56% reduction for the LF of co-digested manure (42–67% recovered of N treated), primarily dependent on resource pricing. This study shows the power of modelling for minimum-cost design and operation of manure treatment yielding savings while producing useful N recovery products with SS followed by NDN.

Minimum Cost Design for Rectangular Isolated Footings Taking into Account That the Column Is Located in Any Part of the Footing

This work presents a new model for obtaining the cheapest design for a rectangular isolated footing, taking into account that the column is located in any part of the footing. The methodology is developed by integration to obtain the moments, bending shear and punching shear according to the American Concrete Institute ACI 318-14. This document presents the simplified and precise equations of the four moments, four bending shears and one punching shear acting on the footing. Some designs have been developed by the trial and error method to determine the footing dimensions, and later the thickness and steel area of the footing are obtained. Some authors present the minimum cost design for a rectangular isolated footing taking into account that the column is located in the center of gravity of the footing, and other authors present very complex algorithms. Numerical examples are presented to obtain the minimum cost design of rectangular isolated footings under biaxial bending, and some results are compared with those of other authors considering the same conditions. The new model presents a smaller contact area with the soil and a lower design cost than those presented by other authors.

Optimal Sewer Network Design for Cities in Hilly Regions

ABSTRACT This paper proposes a method to include drop manholes in the optimal design of sewer networks. These structures dissipate energy and reduce flow velocity, which is important in hilly regions where high slopes induce velocities that exceed the maximum allowable. The methodology proposed here introduces a new type of arc to represent drop manholes in a model that uses graph theory to achieve the minimum cost design of a sewer network. Also, for the estimation of drop manhole costs, a new cost function is developed based on pipe and manhole cost equations proposed in the literature. The methodology was tested in eight different series of pipe configurations, as well as a real sewer network located in Colombia, varying the pipe material and the land slope. The results demonstrated that the proposed methodology allows for the optimal design of sewer networks in hilly regions while satisfying all hydraulic and commercial constraints.

Optimal Location and Line Assignment for Electric Bus Charging Stations

This article considers an optimization problem aiming at planning the service stations to recharge a fleet of electric buses (EBs) for public transportation. The planning problem includes the selection of the sites of the stations (among a set of pre-specified eligible sites) and their sizing (both in terms of the number of sockets and maximum output power). The optimization problem also integrates issues related to the assignment of the various lines to the activated stations and the bus fleet's sizing. The formalization of the optimization problem is carried out by taking into account the nonlinear charging process characteristic of the batteries of EBs. The optimization problem is defined as a minimum cost design while guaranteeing a minimum quality level of the service, represented in this case by a minimum frequency for each of the lines. The overall decision problem turns out to be a mixed nonlinear one. It can be efficiently solved by common commercial software tools for moderate-medium problem sizes, as demonstrated in the presented application.

Thermo-economic analysis of a low-cost greenhouse thermal solar plant with seasonal energy storage

Reduction of greenhouse gas emissions is today mandatory to limit the increase of ambient temperature. This paper provides a numerical study of a thermal solar plant using a seasonal dual-media sensible heat thermal energy storage system for supplying the total energy demand of a greenhouse located in the South of Italy, avoiding the use of the gas boiler. The aim of the work is to assess the technical and economic performance of a low-cost pit storage system, made of gravel and water, placed under the greenhouse to save surface. The study provides an original analysis of the charging and discharging phases during one year of operation on the basis of the real hourly heating demand and on real weather data. A sensitivity analysis of the levelized cost of heat is carried on with respect to the solar-collector area and to the storage-pit volume. The analysis shows that a minimum-cost design solution exists to cover 100% of the heat demand with an estimated levelized cost of heat of 153.3 EUR/MWh. The results demonstrate that dual-media thermal energy storage systems with solar thermal collectors represent a viable solution for reducing the environmental impact of greenhouses.

Parametric analysis of the minimum cost design of flexible pavements

This paper presents recommendations for an optimal pavement design. For this purpose, eight optimization models were developed, each corresponding to a different type of pavement. The optimization models were used to obtain the optimal designs for different design data. These results were used to perform a multi-parametric analysis, from which the design recommendations for an optimal design were derived. Since the optimization was performed for a large number of design-parameter combinations, the manual execution of the optimization algorithm was not feasible. Therefore, the optimization model was developed to include a loop to perform an optimization for each of the combinations. This study discusses the project data in which geosynthetically reinforced flexible pavements outperform conventional flexible pavements. In addition, the results of the study allow a direct comparison between geosynthetic reinforced and unreinforced flexible pavement structures once they are optimized.

On the Evolution of the Optimal Design of WDS: Shifting towards the Use of a Fractal Criterion

Several researchers have proposed methodologies for addressing the problem of designing optimal water distribution systems. Metaheuristic approximations are studied the most due to the vast solution space. In search of reducing computational time, the Non-dominated Sorting Genetic Algorithm II (NSGA-II) has been tested with retrofitting from the Optimal Power Use Surface (OPUS) methodology. A previous study demonstrates how OPUS significantly improves the results since it seeks to reduce energy losses in the network, in order to approximate minimum-cost designs using fewer hydraulic executions. However, more research is still needed to determine applicable hydraulic criteria that allow an enhanced comprehension of optimal designs. Therefore, this paper aims to understand the characteristics of near-optimal solutions using designs from the retrofitted OPUS/NSGA-II Pareto fronts of four distinct networks (Hanoi, Balerma, Fossolo, and Modena). Moreover, fractal characteristics of the networks’ energy dissipation, flow, and diameter distribution have been analyzed for this purpose. In this way, outcomes suggest that the hydraulic gradient line box dimension in optimal designs approaches a value of two, demonstrating that objects resemble a single-plane surface. These promising results propose fractal analysis as a practical design criterion due to its hydraulic significance and low computational cost.

Surrogate-based optimum design of 3D reinforced concrete building frames to Eurocodes

The optimum structural design of real-world 3D concrete building frames to modern design standards is a complex and computationally expensive task. Hence, the use of surrogate-based optimization (SBO) methodologies must be investigated to reduce computational cost. The present study applies, for first time, a fully-fledged SBO algorithm to the optimum design of 3D concrete building frames. More particularly, the algorithm is applied to the minimum material cost design of a 4-storey and a 12-storey 3D RC building according to Eurocodes. It is found that the SBO algorithm can converge earlier than other well-established metaheuristic optimization algorithms reducing considerably the required computational effort. Nevertheless, it is likely to get trapped in local optima for large-scale RC frames. To overcome this drawback, a novel hybrid approach is also proposed herein that offers improved computational performance for large-scale concrete building frames.

Metaheuristic-Based Practical Tool for Optimal Design of Reinforced Concrete Isolated Footings: Development and Application for Parametric Investigation

In the process of designing an economical structure, safety along with total cost must be balanced. This can be attained by design optimization, however the complex nature of the algorithms involved hinders its application. Further, there is a severe lack of research on the optimization of reinforced concrete (RC) isolated footings. Therefore, the main objective of this research is to develop a user-friendly tool for the optimization of RC isolated footings using advanced metaheuristic algorithms to make it more practical and convenient to adopt for design optimization. For this purpose, a spreadsheet-based interface is created in which input parameters from the original design can be entered to find the best option for the minimum cost design. The Evolutionary Algorithm (EA) and the Genetic Algorithm (GA) are used as metaheuristic techniques for optimization. The original design of four examples from the literature is compared with the optimized design obtained from the developed tool to demonstrate its efficiency. For the considered case studies, cost-saving of up to 44% has been obtained. Furthermore, a parametric investigation for the minimum cost objective using the GA has been performed through which a detailed analysis of geometric reinforcement and material strength variables is conducted. The results lead to the derivation of useful thumb rules for the economical design and proportioning of isolated footings.

OPTIMAL DESIGNS OF GRID-CONNECTED ENERGY EFFICIENT AND RESILIENT RESIDENTIAL COMMUNITIES

Abstract As demand continues to grow throughout the United States, new communities have unique opportunities to take advantage of load-side and generation-side integrations with the goal of reducing energy use, improving the environment, and increasing resilience. Most currently reported literature investigates energy efficiency and reduction of building energy consumption or on-site generation and net zero energy goals without resiliency performance analysis. This study examines the impacts of residential building characteristics and energy sources (i.e. electricity and natural gas) on the capacity of the on-site PV generation required to achieve net-zero energy and resiliency goals for a community in Longmont, Colorado. Six community load designs are shown to impact system sizes and costs for on-site generation and resilience. Gas and electrified minimum cost designs reduce source energy from their baselines by 17% and 47% respectively. Gas minimum cost designs reduce initial and annualized energy costs by 487 and247 per year, whereas electrified minimum cost designs increase initial costs by 4, 991 and reduce annualized energy costs by1,266 per year. Resilience designs show that with various outage durations, the longer the outage design case, the larger the system, but the greater the probability of surviving outages throughout the year, with gas communities representing lower probabilities of survivability than electrified communities.

고유진동수 제한을 갖는 골조구조의 GA 기반 최적설계 시스템

Normal strategy of structure optimization procedure has been minimum cost or weight design. Minimum weight design satisfying an allowable stress has been used for the ship and offshore structure, but minimum cost design could be used for the case of high human cost. Natural frequency analysis and forced vibration one have been used for the strength estimation of marine structures. For the case of high precision experiment facilities in marine field, the structure has normally enough margin in allowable stress aspect and sometimes needs high natural frequency of structure to obtain very high precise experiment results. It is not easy to obtain a structure design with high natural frequency, since the natural frequency depend on the stiffness to mass ratio of the structure and increase of structural stiffness ordinary accompanies the increase of mass. It is further difficult at the grillage structure design using the profiles, because the properties of profiles are not continuous but discrete, and resource of profiles are limited at the design of grillage structure. In this paper, the grillage structure design system under the constraint of high natural frequency is introduced. The design system adopted genetic algorithm to realize optimization procedure and can be used at the design of the experimental facilities of marine field such as a towing carriage, PMM, test frame, measuring frame and rotating arm.

A generative design-to-BIM workflow for minimum weight plane truss design

Structural design has a significant impact on the overall cost of truss structures. In order to reduce the cost of a structure it is important to support designers' decision making starting from the early design phase. In this study, an optimization workflow is proposed, developed and implemented using well known generative design and Building Information Modeling (BIM) tools to achieve a cost-optimal design of a truss structure in the early design phase. Generative design aims to develop products that are lighter, stronger, more efficient and tailored to the specific needs of end users. Generative design tools allow users to create efficient designs via optimizing factors such as cost, weight, energy efficiency and performance. The aim of this study was to develop an optimization workflow to find and model the minimum weight / minimum cost design alternative in the early design phase using generative design, structural analysis and BIM tools in an integrated manner. The goal for the optimization was determined as finding the minimum weight (thus minimum cost) structure among the generated design alternatives. The single span steel truss was selected as the structure to be optimized, and optimization scenarios were prepared and implemented to determine the structural components of the truss with minimum weight. The results demonstrated that through integrated use of structural analysis, generative design and BIM tools minimum-weight truss design can be realized easily and practically.

Optimum Design of Reinforced Concrete T-Beam Considering Environmental Factors via Flower Pollination Algorithm

The minimum cost designs may be costly for the environment. In that case, the cost is not only a single objective in the design of structures. In that situation, CO2 emission minimization can be considered in the optimum design. In this study, reinforced concrete (RC) T-beams were optimized via flower pollination algorithm for the environmental factor minimizing the CO2 emission of the materials. The investigation was done for 4 cases of CO2 emission values and these cases were compared with 5 cases of the cost ratios of concrete and steel. Due to this investigation, it was found that CO2 emission optimization is effective in the reduction of the CO2 emission value by 4.5% compared to cost optimization. If the ratios of CO2 emission and the cost of steel per concrete are different, the optimum design variables and objectives are different. Also, the use of recycled steel is %.30.24 more effective on the reduction of CO2 emission and saving the planet.

Seismic design of multiple‐rocking systems: A gradient‐based optimization approach

AbstractSelf‐centering concentrically braced frames (SC‐CBFs) have shown many advantages towards structural damage‐free seismic behavior. These systems could be designed either with a single rocking section at the base or with multiple rocking sections along their height. Initial design methodologies for both cases have been proposed with an emphasis on the former case. These methods focused on simplicity of the design process and mostly relied on parametric studies. Thus, the obtained designs may violate some displacement constraints when verified using nonlinear time history analysis (NLTHA) or lead to conservative designs that may be expensive. Furthermore, focusing on simplicity, these methods are tailored for regular structures. This paper takes a different approach that leads to minimum cost designs for irregular structures that satisfy the constraints exactly when verified using NLTHA. The proposed approach allows for multiple rocking sections along the height of the designed buildings, if these lead to cost reductions. Of course, this comes with more demanding computing resources. Nevertheless, these are kept reasonable for practical use on a personal computer. For that purpose, the NLTHA is performed using the computationally efficient Mixed Lagrangian Formalism. Furthermore, an efficient gradient‐based optimization framework is developed. The framework is applied for the design of 8, 12, and 20‐story spine SC‐CBFs and an irregular 12‐story building with a setback level. These have shown promising results while revealing also non‐traditional designs. This demonstrates the power of using optimization for the design of these lateral load resisting systems.