Minimum Construction Cost Research Articles

Multi-objective site selection optimization of the gas-gathering station using NSGA-II

Abstract The gas-gathering station (GGS) is a key component in the gas field, and its site selection is an important issue for designers. Since the diffusion of gas from the station may pollute the surrounding environment, it is a trend to consider the environmental and economic factors in the site selection of GGSs. In this study, a model is developed with the objective functions of minimal construction costs and environmental impact. We apply NSGA-II to search for the Pareto frontier and couple A* algorithm to find the optimal routes, and we use the Monte Carlo method to sample the uncertain wind data and evaluate the environmental impact. The effectiveness of the proposed method is demonstrated in a design problem in a gas field. The optimal construction site for the GGS is solved by the proposed method. The results show that this work can serve as a decision-support tool for the design of GGS.

A method to optimize mobile crane and crew interactions to minimize construction cost and time

Abstract Cranes often play a central role in transporting materials on building construction sites and are therefore critical to project cost and schedule. This paper presents a new model to simulate the interactions between mobile cranes and associated work crews onsite. The model considers crane type and position, the sequence of components transported, and the number and size of crews at the demand point. A novel hybrid multi-objective Genetic Algorithm (MOGA) is utilized to identify optimal crane and crew configurations that minimize construction cost and duration. The proposed method is demonstrated on an example problem involving the installation of curtain wall panels for a mid-rise office building. The results indicate that considering crane and crew decisions in parallel reduces installation cost by 19.5% and duration by 1.7% compared to considering these decisions sequentially. Furthermore, the number of crews used and the number of crane stops had the most significant impact on project cost and schedule, respectively.

Restoring the eastern oyster: how much progress has been made in 53 years?

Coastal ecosystem restoration is accelerating globally as a means of enhancing shoreline protection, carbon storage, water quality, fisheries, and biodiversity. Among the most substantial of these efforts have been those focused on re‐establishing oyster reefs across the US Atlantic and Gulf coasts. Despite considerable investment, it is unclear how the scale of and approaches toward oyster restoration have evolved. A synthesis of 1768 projects undertaken since 1964 reveals that oyster substrate restoration efforts have primarily been concentrated in the Chesapeake Bay and the Gulf Coast, have been heavily reliant on oyster shell, and have re‐established 4.5% of the reef area that has been lost across all regions. By comparing costs to ecosystem service benefits, we discovered that the return‐on‐investment of oyster restoration varies widely, but generally increases with project size. To facilitate the recovery of coastal ecosystems and their services, scientists and resource managers must adopt a new restoration paradigm prioritizing investment in sites that maximize economic and ecological benefits and minimize construction costs.

Sustainable design for reinforced concrete columns through embodied energy and CO2 emission optimization

This study presents a sustainable design method that optimizes the embodied energy and carbon dioxide (CO2) emissions of a reinforced concrete (RC) column. Conventionally, the design of RC structures has been focused on the minimization of construction costs while satisfying the structural design code. Recently, however, sustainability aspect in structural design has drawn big attention to structural engineers, especially for structure life cycle assessment. Therefore, it is crucial to understand the relationship between construction costs and consumption of energy including CO2 emissions, in the design process of RC structures. In the sustainable design process, the objective functions for the cost, embodied energy, and CO2 emissions were set and numerous optimization analyses for various loading conditions were conducted as the failure mode of RC columns varies according to the eccentricity involving the axial forces and moment. A thorough investigation of the optimization analysis results shows that, when a 10% cost increase is assumed, the embodied energy and CO2 emissions might undergo an overall reduction of up to 22% and 63%, respectively. As a result, the proposed design method enables the embodied energy and CO2 emissions to be effectively optimized in the conventional design process of RC columns.

Optimization of steel frame building systems in terms of parameters and reliability requirements

The problem of ensuring safety and reliability of building structures in modern socio-economic conditions is especially urgent. An important aspect of this issue is to determine the rational costs of manufacturing the load-bearing systems. This should take into account the possible emergency situations and their consequences. The purpose of the present studies is to create a methodology for the optimal design of normally operated steel frames considering material and social losses from the possible failure of structural elements. A method for parametric optimization of steel frame systems during selection of rod cross-sections and structure reliability levels is developed. The problem is to minimize structure manufacturing costs and recover damage caused by any material and social losses in the event of possible malfunctions and damage. Constraints on the strength, stiffness, and stability of the frame have all been taken into consideration. A two-stage optimization scheme is proposed. The first stage includes several parametric optimization processes using a genetic algorithm with minimization of construction costs for various system load levels. Then the structure's reliability is assessed within a probabilistic formulation for each of the obtained parameter combinations. Eventually variant of the frame is selected based on the minimum sum of the manufacturing cost and the expected value of material and social losses possible during operation period of the structure, expressed in monetary terms. An example of optimum design of a spatial frame with personnel present in the areas of possible damage is considered. The presented method allows implementing a comprehensive approach to optimum designing, while taking into account both the manufacturing cost and the possible failures of the constructive system.

Construction Cost Minimization of Shallow Foundation Using Recent Swarm Intelligence Techniques

In this study, the performances of eight recent swarm intelligence techniques, accelerated particle swarm optimization (APSO), firefly algorithm, levy-flight krill herd, whale optimization algorithm (WOA), ant lion optimizer, grey wolf optimizer, moth-flame optimization algorithm and teaching-learning-based optimization algorithm (TLBO), are explored. Particle swarm optimization algorithm is also considered to benchmark the efficiencies. A final cost is considered as an objective function which deals with shallow footing optimization with two attitudes: routine optimization, and sensitivity analysis. Moreover, as a further study, the effect of the location of the column at the top of the foundation is examined by adding two spare design variables. To this end, three numerical case studies are simulated. Based on the final results TLBO showed an acceptable performance because of the lowest mean values and WOA demonstrated the weakest efficiency among the algorithms in this study.

Computing the minimum construction cost of a building’s external wall taking into account its energy efficiency

The construction of a building’s external wall is subject to many restrictions such as budget, workforce, availability of materials, thickness, maintenance cost, time limit and specially, energy efficiency legislation intended at mitigating the negative effects of the energy consumption and obtaining a more sustainable and healthier indoor environment. The choice of the appropriate material and thickness composing each layer of an external wall can significantly reduce the energy consumption of the building without adversely affecting the cost of the wall. By using Integer Linear Programming (ILP), the aim of this paper is to obtain this best choice of materials and thicknesses to minimize the construction cost of an external wall while complying with the abovementioned restrictions. A case study is presented with more than 5.5 million combinations of different selected materials and their thicknesses for the different layers of the wall. The ILP problem has been solved for 165 scenarios that take into account different maximal allowed thermal transmittances and a range of the most usual thicknesses and material options of an external wall.

Applied Mathematical Approach for Decision-Making in Building Plan Design

This article presents a method for solving decision in building plan design by using a mathematical model (nonlinear programming). First objective is to formulate mathematical models for analysis in dividing rooms and dimensions in a building plan. Secondly, to calculate the dimensions and room sizes which have minimum construction cost. A case study of a condominium building plan was analyzed in this research. The results found application of the mathematical model was applicable. The mathematical models were formulated, the minimum construction cost was ฿723,000 (US$24,100) and usable area in the condominium was 67.5 m2 and followed the assigned design constraints.Keywords: Building plan design; Mathematical model; Unit cost;eISSN 2398-4295 © 2018. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open-access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia. DOI:

SIMILITUDE AND THERMAL PERFORMANCE ON NON-CONVENTIONAL ROOFS

The objectives of this study were to evaluate the thermal comfort and the similitude between prototypes and reduced models, using non-conventional coverage with green roof and expanded clay aggregate, supported on wood frame structure. For this, were determined the Black Globe Temperature and Humidity Index (BGHI), the Human Discomfort Index (HDI), Effective Temperature (ET), Air Temperature (Tair) and Radiant Thermal Load (RTL), from March 2013 to December 2014. The results showed that there were no statistical differences to 5% significance in predicting heat indices between the prototypes and models. Observing all indexes simultaneously, it was observed that January was the month what led to the worst heat conditions, while June and July showed the worst cold conditions. It can be concluded that the use of reduced models is possible (1:2) compared to the prototype (1:1), with green roofs and expanded clay as covering element, for the prediction of thermal indexes, minimizing construction costs and use of spaces.

Minimization of Construction Costs for an All Battery-Swapping Electric-Bus Transportation System: Comparison with an All Plug-In System

The greenhouse gases and air pollution generated by extensive energy use have exacerbated climate change. Electric-bus (e-bus) transportation systems help reduce pollution and carbon emissions. This study analyzed the minimization of construction costs for an all battery-swapping public e-bus transportation system. A simulation was conducted according to existing timetables and routes. Daytime charging was incorporated during the hours of operation; the two parameters of the daytime charging scheme were the residual battery capacity and battery-charging energy during various intervals of daytime peak electricity hours. The parameters were optimized using three algorithms: particle swarm optimization (PSO), a genetic algorithm (GA), and a PSO–GA. This study observed the effects of optimization on cost changes (e.g., number of e-buses, on-board battery capacity, number of extra batteries, charging facilities, and energy consumption) and compared the plug-in and battery-swapping e-bus systems. The results revealed that daytime charging can reduce the construction costs of both systems. In contrast to the other two algorithms, the PSO–GA yielded the most favorable optimization results for the charging scheme. Finally, according to the cases investigated and the parameters of this study, the construction cost of the plug-in e-bus system was shown to be lower than that of the battery-swapping e-bus system.

Automated spatial design of multi-story modular buildings using a unified matrix method

Abstract Automated design methods facilitate the study of the influence of design forms on the buildings' behavior, and help compare the performance of alternative designs more effectively. This paper presents a Unified Matrix Method, as an effective automated method that aids in the search for the best compromised spatial design of multi-story modular buildings during the early stages of the design process. The method is presented in a general format employing a balanced approach that integrates different design aspects together, namely constructional, architectural and structural aspects. First, it describes how the spatial design of multi-story modular buildings can be generally represented by three-dimensional matrices arisen from combinatorial problems. Then, the spatial design is modeled by a design structure matrix, which decomposes the building into smaller components such as modular units, connections, stabilizing and bracing systems. Finally, a three-dimensional assignment problem is formulated to solve the problem. Particular conditions or preferences for the spatial design can be incorporated as constraints on the assignment problem. In order to show the robustness of the method, an actual case study is designed and employed, with the aim of obtaining a spatial design having minimum construction cost, maximum plan regularity and maximum energy efficient form.

Increased fly ash utilization — value addition through forest road reconstruction

Increasing forest bioenergy utilization is increasing the need to discover more applications for fly ash to avoid dumping charges. Our study concentrates on defining the work phases of reconstruction work and estimation of construction costs for a method using biomass based fly ash. Cost calculations were carried out for two mixed structures of fly ash and aggregate, two uniform structures of fly ash, and a conventional aggregate structure, where construction material volumes were calculated per kilometre for each structure. Our study defined suitable machines and their productivity per hour for different work phases. Cost calculation equations were formed for the used machines and the transportation of construction materials. Our study showed that building a 250 mm thick uniform layer of fly ash was the best alternative for minimizing construction costs. However, building a 500 mm thick uniform layer of fly ash was the best alternative for minimizing dumping charges.

Life Cycle Costing as an Important Contribution to Feasibility Study in Construction Projects

The purpose of this paper is to highlight the role of life cycle cost (LCC) analysis in the feasibility study of construction projects, especially in the public sector. Feasibility study is usually conducted in the early phase of construction projects when the greatest benefit of LCC can be obtained. The commonly used construction cost minimization approach should be replaced with LCC optimization. In order to achieve the maximum value for money, all costs incurred over the whole life span must be evaluated. Life cycle costing is a method of economic analysis directed at all costs related to constructing, operating, and maintaining a construction project over a defined period of time. The optimization of the LCC of a project, construction or equipment, is essential for the complex decision-making process. It is then at this point that the solution with the minimum value of LCC can be chosen. The public sector in the Czech Republic is now beginning to require quantification of LCC when deciding on construction. In addition, LCC has become a criterion in public tenders. This paper summarizes the experience of assessing building designs in terms of LCC. Not only public sector benefits are identified and summarized but also some significant difficulties. Case studies are provided.

Behavior of post-tensioned dry-stack interlocking masonry walls under out of plane loading

The researches done on wall construction to make it appropriate, easy, fast and cost effective have led to a promising technique known as “Dry-stack interlocking masonry system”. Nevertheless, there are several disadvantages attributed to using this system. One of the major drawbacks of this system is the low bending capacity that can be resisted by the interlocking keys alone. To overcome this problem grouting and reinforcing of the hollow block cells are required, which make the system a bit expensive. Additionally, the dry-stacked units had to settle down to balance uneven surfaces and notches, which may reduce strength and stiffness of the walls. One method that has been suggested to minimize this drawback is post-tensioning (PT) of these walls to eliminate grout and enhance the bending capacity.The objective of the current research is to investigate the behavior of PT dry-stacked interlocking masonry (DSIM) walls constructed using locally available masonry units and PT bars under out-of-plane loading. Some of the expected factors that could affect the performance of these systems are construction system, grouting effect, PT technique and restraining effect of PT bars. The test results demonstrated that PT-DSIM systems considered in the current study, under out-of-plane loading, behaved similar to the conventionally reinforced masonry walls. In addition, the proposed PT technique proved its efficiency for grouted walls. It can achieve a remarkable increase in the cracking load triple that of the ordinary reinforced walls and in addition to improving the durability and enhancing the appearance. Furthermore, ungrouted PT walls proved to be the most effective construction detail. Since, their specific strength (capacity/weight) ranges between 1.3 and 1.6 times that of grouted PT walls, in addition to taking the advantage of minimizing construction cost, time, and weight of the structure.

Efficient twin aperture magnets for the future circular e+/e_ collider

We report preliminary designs for the arc dipoles and quadrupoles of the FCC-ee double-ring collider. After recalling cross sections and parameters of warm magnets used in previous large accelerators, we focus on twin aperture layouts, with a magnetic coupling between the gaps, which minimizes construction cost and reduces the electrical power required for operation. We also indicate how the designs presented may be further optimized so as to optimally address any further constraints related to beam physics, vacuum system, and electric power consumption.

Water Quality Based Multi-objective Optimal Design of Water Distribution Systems

Water distribution systems (WDSs) are one of the vital infrastructures in urban areas. The common objective considered in WDSs design is providing required water with the minimum construction cost. Less attention is paid to “water quality” as an objective in optimal design of WDSs. The aim of this paper is to include a water quality based objective in WDS design alongside other common objectives. For this purpose, the water quality reliability index developed based on “chlorine residual” and “water age”, is used. EPANET2.0 is applied for WDS simulation and ACO (Ant-Colony-Optimization) has been used as the optimization algorithm. Head-Driven-Simulation-Method (HDSM) is also considered. The proposed model is applied to Jahrom (a city in the south of Iran) WDS. The outputs show that the proposed model would result in less construction costs in comparison to the original design and 4–10 % of construction cost can be reduced depending on the considered objectives and selected optimal solution by managers and decision makers while the resulted solutions include high water quality reliability (ranging from 93 to 99 %). Also using HDSM method for hydraulic analysis of WDS instead of DDSM can lead to solutions with less construction cost (U$10,000 in average) and acceptable water quality reliability.

Minimizing the costs of constructing an all plug-in electric bus transportation system: A case study in Penghu

The growth of worldwide environmental awareness has prompted numerous countries to focus on developing energy-conservation and carbon-reduction technology. The advancement of such technology enables the emergence of low-noise, low-polluting alternatives for bus systems, such as hybrid-electric, battery-electric, and fuel-cell electric buses (e-buses). For such buses to serve the existing schedules and lines operated by their conventional counterparts, reorganizing bus transportation systems is a major challenge and entails construction costs that comprise the costs of e-buses, battery capacity, chargers, and bus scheduling.To facilitate the development of environmentally friendly public transportation, this study proposes a model for simulating the operation and battery charging schedule of plug-in e-buses on the basis of an existing schedule and line network. The model was used to estimate the overall construction cost of converting the existent bus transportation system into an all plug-in e-bus one. Focusing on the bus transportation system in Penghu, an archipelago of Taiwan, this case study examined the effects of day- and nighttime charging requirements on the construction cost of an e-bus transportation system to improve the practicability of e-buses. It also applied a genetic algorithm to determine the minimum construction cost, which varied depending on the number of e-buses, level of battery capacity, number of chargers, and electricity costs. The optimized parameters involved the hourly residual battery capacity and battery charging times during the daytime operating hours. The results showed that although daytime charging involved electricity uses during peak hours and thus incurred additional costs, it contributed to the use of e-buses and an overall reduction in the construction cost. In summary, the proposed optimization method would successfully reduce the construction cost of the Penghu e-bus transportation system.

Shuffled Frog-Leaping Algorithm for Optimal Design of Open Channels

AbstractOpen channels are important water structures for irrigation, water supply, power generation, and drainage. The primary concern of designing a channel is to determine optimum dimensions while minimizing construction costs. In this paper, a memetic metaheuristic algorithms called “shuffled frog-leaping algorithm” (SFLA) is used to optimize sampling design variables of composite open channels. The results of optimization using SFLA and a generic language for interactive general optimization (LINGO) software are compared with other metaheuristic algorithms, such as genetic algorithm (GA), simulated annealing (SA), Lagrange multiplier method (LMM), ant colony optimization (ACO), improved ant colony optimization (IACO), and particle swarm optimization (PSO). Four common nonlinear models in open-channel designing are considered in this study: (1) model I (M1), which applies an equivalent roughness coefficient without any sectional division following the Manning equation; (2) model II (M2), which consider...

Multi-criteria analysis of variation solutions for the pipeline route by applying the PROMETHEE method

Preliminary notes The paper considers the problem of selecting the most appropriate variation for the pipeline route Belosevac Divci within the Kolubara regional water supply system (Serbia). Variations are evaluated according to five criteria, three of which have an economic character. The problem of selecting the optimal variant for the pipeline route is solved using the multi-criteria analysis by applying the PROMETHEE method and the implementation into the software package Visual PROMETHEE 1.4. The PROMETHEE method has proved to be applicable and suitable in solving practical problems related to civil engineering, in the phase of the final decision-making in the area of construction planning. The application of multi-criteria evaluation methodology, provided in this paper, proposes the variant with the minimal construction costs.

Effect of palm oil clinker (POC) aggregates on fresh and hardened properties of concrete

Utilizing waste material in the construction industry is an effective way to protect the environment and minimize construction cost. In this paper, palm oil clinker (POC) aggregates were used as coarse and fine aggregate replacement in lightweight concrete production. This study focused mainly on investigating the effect of both partial and full replacement of the aggregates with POC on the physical and mechanical properties of concrete. Department of Environment (DOE) method was adopted for the mix design to produce concrete Grade 40. The approach used in the mix design involved POC replacement of 0%, 10%, 20%, 40%, 60%, 80%, and 100% of the total volume of fine and coarse aggregates. The parameters investigated in this study include the slump and density for the fresh properties, as well as the compressive strength and ultrasonic pulse value (UPV) tests at 3, 7, 14, and 28days for the hardened properties. The hardened density at 28days was within the range of 2074–2358kg/m3. Test results showed that POC exhibited good UPV value and an acceptable compressive strength of 33–49MPa at 28days. Thus, POC has a good potential to replace natural aggregates, making it suitable to be used in concrete.