International Journal of Environmental Research and Public Health, 2020
The construction industry of all countries in the world is facing the issue of sustainable develo... more The construction industry of all countries in the world is facing the issue of sustainable development. How to make effective and accurate decision-making on the three pillars (Environment; Economy; Social influence) is the key factor. This manuscript is based on an accurate evaluation framework and theoretical modelling. Through a comprehensive evaluation of six cable-stayed highway bridges in the entire life cycle of five provinces in China (from cradle to grave), the research shows that life cycle impact assessment (LCIA), life cycle cost assessment (LCCA), and social impact life assessment (SILA) are under the influence of multi-factor change decisions. The manuscript focused on the analysis of the natural environment over 100 years, material replacement, waste recycling, traffic density, casualty costs, community benefits and other key factors. Based on the analysis data, the close connection between high pollution levels and high cost in the maintenance stage was deeply promot...
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
This paper addresses a study of cost-optimal road modular hinged frames. The performance of three... more This paper addresses a study of cost-optimal road modular hinged frames. The performance of three hybrid metaheuristics is assessed through a fractional factorial design of experiments. The results allow for selecting and calibrating the hybrid simulated annealing to solve the combinatorial optimization problem. By varying the horizontal span from 8 to 16 meters and the earth cover from 1 to 5 meters, 25 different structural configurations are studied. The calibrated methodology is applied to obtain nine different frames with optimal costs for each configuration. The study of the economic, environmental and geometrical characteristics of the 225 optimum structures allows for the development of a regression analysis. With R2 correlation coefficients close to the unit, the expressions form a valuable tool for calculating the final cost, associated emissions, embodied energy and particular geometric characteristics. The optimum structures present slender and densely reinforced designs....
Sustainable development requires improvements in the use of natural resources. The main objective... more Sustainable development requires improvements in the use of natural resources. The main objective of the present study was to optimize the use of materials in the construction of reinforced concrete precast hinged frames. Proprietary software was developed in the Python programming language. This allowed the structure’s calculation, verification and optimization through the application of metaheuristic techniques. The final cost is a direct representation of the use of materials. Thus, three algorithms were applied to solve the economic optimization of the frame. By applying simulated annealing, threshold accepting and old bachelor’s acceptance algorithms, sustainable, non-traditional designs were achieved. These make optimal use of natural resources while maintaining a highly restricted final cost. In order to evaluate the environmental impact improvement, the carbon-dioxide-associated emissions were studied and compared with a reference cast-in-place reinforced concrete frame. The...
This paper represents new approaches for calculating, designing, and optimizing prestressed arche... more This paper represents new approaches for calculating, designing, and optimizing prestressed arched trusses with a tie member. Structural systems with long spans, such as trusses, beams, frames, etc., are subjected to a considerable/substantial risk of losing load-carrying capacity because of the different types of loads used. Some traditional design methods define the values of prestressing force in the tie member and internal forces in the truss elements to avoid this load capacity loss. However, the accuracy and limits of the determination of the forces are not necessarily known. The authors offer a new type of prestressed arched truss and some new approaches in the design and calculation process to solve these disadvantages. The study’s main objectives were to design an innovative and new geometric form of prestressed arched truss, which allows the development of high-value prestressing force, to optimize a new truss for reducing self-weight, increasing load-carrying capacity com...
Journal of Construction Engineering, Management & Innovation
This paper presents a study of the parametric variability of post-tensioned concrete box-girder p... more This paper presents a study of the parametric variability of post-tensioned concrete box-girder pedestrian bridges. SAMO2 algorithm is used for the parametric study. This algorithm combines SA with a mutation operator, to find the economic solutions. A span-length parametric study analyzes the characteristics for the best design of a three-span deck in which the main span ranges from 30 to 60 m. The depth and the number of strands were adjusted according to span length, while the thickness of the slabs presented the same optimum values in all cases. Results show that the amount of steel and volume of concrete per square meter of deck shows a good correlation with the main span length. This study demonstrates that by increasing the main span length by one meter, the total cost per square meter of the deck increases by 6.38 euros on average. Thus, this paper shows the relationship between the span length and geometrical and steel variables to produce and build a cost-efficient pedestrian bridge.
This paper deals with optimizing embedded carbon dioxide (CO2) emissions using surrogate modeling... more This paper deals with optimizing embedded carbon dioxide (CO2) emissions using surrogate modeling, whether it is the deck of a post-tensioned cast-in-place concrete slab bridge or any other design structure. The main contribution of this proposal is that it allows optimizing structures methodically and sequentially. The approach presents two sequential phases of optimization, the first one of diversification and the second one of intensification of the search for optimums. Finally, with the amount of CO2 emissions and the differentiating characteristics of each design, a heuristic optimization based on a Kriging metamodel is performed. An optimized solution with lower emissions than the analyzed sample is obtained. If CO2 emissions were to be reduced, design recommendations would be to use slendernesses as high as possible, in the range of 1/30, which implies a more significant amount of passive reinforcement. This increase in passive reinforcement is compensated by reducing the mea...
At present, reducing the impact of the construction industry on the environment is the key to ach... more At present, reducing the impact of the construction industry on the environment is the key to achieving sustainable development. Countries all over the world are using software systems for bridge environmental impact assessment. However, due to the complexity and discreteness of environmental factors in the construction industry, they are difficult to update and determine quickly, and there is a phenomenon of data missing in the database. Most of the lost data are optimized by Monte Carlo simulation, which greatly reduces the reliability and accuracy of the research results. This paper uses Bayesian advanced fuzzy mathematics theory to solve this problem. In the research, a Bayesian fuzzy mathematics evaluation and a multi-level sensitivity priority discrimination model are established, and the weights and membership degrees of influencing factors were defined to achieve comprehensive coverage of influencing factors. With the support of theoretical modelling, software analysis and f...
This paper deals with the seismic column design of 35 elevated RC water storage tanks. Tanks comp... more This paper deals with the seismic column design of 35 elevated RC water storage tanks. Tanks comprise a top conic trunk reservoir, a column with variable hollow square cross-sections, and a shallow foundation on a sand layer. The five-column heights considered are 20, 25, 30, 35, and 40 m. The five tanks are subjected to seven degrees of seismic loading characterized by the reference peak ground acceleration in Eurocode 8. The elevated tanks are designed against the full prescriptions of Eurocode 2, Eurocode 8, and the Spaniard Structural Code of Practice. This includes variable loads for seismicity, wind, snow, etc., together with the action of self-weight and dead loads. The optimization design method considered is a variant of the old bachelor algorithm, an adaptive threshold acceptance method with a neighborhood move based on the mutation operator from genetic algorithms. Column results show the high nonlinearity of the problem since the horizontal seismic forces depend on the r...
The aim of this paper is to establish an international framework for sustainable project manageme... more The aim of this paper is to establish an international framework for sustainable project management in engineering, to make up the lack of research in this field, and to propose a scientific theoretical basis for the establishment of a new project management system. The article adopts literature review, mathematical programming algorithm and case study as the research method. The literature review applied the visual clustering research method and analyzed the results of 21-year research in this field. As a result, the project management system was found to have defects and deficiencies. A mathematical model was established to analyze the composition and elements of the optimized international project management system. The case study research selected large bridges for analysis and verified the superiority and practicability of the theoretical system. Thus, the goal of sustainable development of bridges was achieved. The value of this re-search lies in establishing a comprehensive i...
This paper deals with a short postgraduate course in automated design and economic optimization o... more This paper deals with a short postgraduate course in automated design and economic optimization of prestressed concrete bridges typically used in public road construction. The course forms part of a recent MSc course in Concrete Engineering which has started in October 2007. The course is concerned first with the basic heuristic algorithms for structural optimization, such as genetic algorithms, ant colonies, simulated annealing, tabu search, threshold acceptance, particle swarm optimization, neural networks, etc. And it then moves to the application of such algorithms to the practical design of real concrete structures such as walls, road portal and box frames, building frames, vaults, bridge piers, abutments and decks. Two design cases are presented. Simulated annealing (SA) is firstly applied to a prestressed concrete precast beam of 30-30 meters of longitudinal spans and 12.00 m of width. The beam has a double U-shape cross-section with beam spacing of 6 m. This example has 59 discrete design variables for the geometry of the beam and the slab, materials in the two elements and active and passive reinforcement. The SA method indicates savings of about 5% with respect to a traditional design. The second type of structure analysed is a 30-30 m prestressed concrete road bridge deck. This example has 27 discrete variables. Threshold accepting method (TA) indicates savings of about 7.5% with respect to the design based on the experience of the bridge designers. Finally, case studies indicate that heuristic optimization is a forthcoming option for improving the design costs of real prestressed bridge decks.
Document downloaded from: This paper must be cited as: The final publication is available at Copy... more Document downloaded from: This paper must be cited as: The final publication is available at Copyright
This paper presents one approach to the analysis and design of post-tensioned cast-in-place concr... more This paper presents one approach to the analysis and design of post-tensioned cast-in-place concrete slab bridge decks. A Simulated Annealing algorithm is applied to two objective functions: (i) the economic cost; and (ii) the embodied energy at different stages of production materials, transport, and construction. The problem involved 33 discrete design variables: five geometrical ones dealing with the thickness of the slab, the inner and exterior web width, and two flange thicknesses; concrete type; prestressing cables, and 26 variables for the reinforcement set-up. The comparison of the results obtained shows two different optimum families, which indicates that the traditional criteria of economic optimization leads to inefficient designs considering the embodied energy. The results indicate that the objectives are not competing functions, and that optimum energy designs are close to the optimum cost designs. The analysis also showed that the savings of each kW h of energy consum...
This paper describes a methodology to design reinfo rced concrete (RC) cantilever earth-retaining... more This paper describes a methodology to design reinfo rced concrete (RC) cantilever earth-retaining walls typically used in road construction based on minimum embedded CO2 emissions. The traditional approach to design does not fully optimize the use of materials. However, s t uctural optimization methods are a clear alternat ive to designs based only on experience. Here, the design involves optimization by a simulated annealing (SA) algorit hm applied to two objective functions, namely the embedded CO 2 emissions and the economic cost of reinforced conc rete walls. The formulation of the problem includes 20 d esign variables: four geometrical ones dealing with the thickness of the kerb and the footing, as well as t he toe and the heel lengths; four material types; a nd 12 variables for the reinforcement set-up. All the structural co nstraints have been imposed using Spanish codes, as well as habitual recommendations in this type of projects. Results from the SA algorithm application i...
This paper deals with the economic optimization of reinforced concrete walls, portal and box fram... more This paper deals with the economic optimization of reinforced concrete walls, portal and box frame structures typically used in road construction. It shows the efficiency of heuristic optimization by the simulated annealing algorithm. The evaluation of solutions follows the Spanish Code for structural concrete. Stress resultants and envelopes of framed structures are computed by an external finite element program. Design loads are in accordance with the national IAP Code for road bridges. The algorithm is first applied to RC retaining walls with 26 continuous design variables of geometry, materials and reinforcement. Results on this topic show the importance of limiting the deflection of walls. No restriction leads to slender solutions with deflections of up to 1/40 the height of the wall. Such elements are unfeasible and, hence, a limitation of 1/150 of the height is adopted for the design of these structures. The second structure analysed is a 10 m horizontal span RC portal frame....
International Journal of Environmental Research and Public Health, 2020
Due to the rapid growth of the construction industry’s global environmental impact, especially th... more Due to the rapid growth of the construction industry’s global environmental impact, especially the environmental impact contribution of bridge structures, it is necessary to study the detailed environmental impact of bridges at each stage of the full life cycle, which can provide optimal data support for sustainable development analysis. In this work, the environmental impact case of a three-tower cable-stayed bridge was analyzed through openLCA software, and more than 23,680 groups of data were analyzed using Markov chain and other research methods. It was concluded that the cable-stayed bridge contributed the most to the global warming potential value, which was mainly concentrated in the operation and maintenance phases. The conclusion shows that controlling the exhaust pollution of passing vehicles and improving the durability of building materials were the key to reducing carbon contribution and are also important directions for future research.
International Journal of Environmental Research and Public Health, 2020
The construction industry of all countries in the world is facing the issue of sustainable develo... more The construction industry of all countries in the world is facing the issue of sustainable development. How to make effective and accurate decision-making on the three pillars (Environment; Economy; Social influence) is the key factor. This manuscript is based on an accurate evaluation framework and theoretical modelling. Through a comprehensive evaluation of six cable-stayed highway bridges in the entire life cycle of five provinces in China (from cradle to grave), the research shows that life cycle impact assessment (LCIA), life cycle cost assessment (LCCA), and social impact life assessment (SILA) are under the influence of multi-factor change decisions. The manuscript focused on the analysis of the natural environment over 100 years, material replacement, waste recycling, traffic density, casualty costs, community benefits and other key factors. Based on the analysis data, the close connection between high pollution levels and high cost in the maintenance stage was deeply promot...
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
This paper addresses a study of cost-optimal road modular hinged frames. The performance of three... more This paper addresses a study of cost-optimal road modular hinged frames. The performance of three hybrid metaheuristics is assessed through a fractional factorial design of experiments. The results allow for selecting and calibrating the hybrid simulated annealing to solve the combinatorial optimization problem. By varying the horizontal span from 8 to 16 meters and the earth cover from 1 to 5 meters, 25 different structural configurations are studied. The calibrated methodology is applied to obtain nine different frames with optimal costs for each configuration. The study of the economic, environmental and geometrical characteristics of the 225 optimum structures allows for the development of a regression analysis. With R2 correlation coefficients close to the unit, the expressions form a valuable tool for calculating the final cost, associated emissions, embodied energy and particular geometric characteristics. The optimum structures present slender and densely reinforced designs....
Sustainable development requires improvements in the use of natural resources. The main objective... more Sustainable development requires improvements in the use of natural resources. The main objective of the present study was to optimize the use of materials in the construction of reinforced concrete precast hinged frames. Proprietary software was developed in the Python programming language. This allowed the structure’s calculation, verification and optimization through the application of metaheuristic techniques. The final cost is a direct representation of the use of materials. Thus, three algorithms were applied to solve the economic optimization of the frame. By applying simulated annealing, threshold accepting and old bachelor’s acceptance algorithms, sustainable, non-traditional designs were achieved. These make optimal use of natural resources while maintaining a highly restricted final cost. In order to evaluate the environmental impact improvement, the carbon-dioxide-associated emissions were studied and compared with a reference cast-in-place reinforced concrete frame. The...
This paper represents new approaches for calculating, designing, and optimizing prestressed arche... more This paper represents new approaches for calculating, designing, and optimizing prestressed arched trusses with a tie member. Structural systems with long spans, such as trusses, beams, frames, etc., are subjected to a considerable/substantial risk of losing load-carrying capacity because of the different types of loads used. Some traditional design methods define the values of prestressing force in the tie member and internal forces in the truss elements to avoid this load capacity loss. However, the accuracy and limits of the determination of the forces are not necessarily known. The authors offer a new type of prestressed arched truss and some new approaches in the design and calculation process to solve these disadvantages. The study’s main objectives were to design an innovative and new geometric form of prestressed arched truss, which allows the development of high-value prestressing force, to optimize a new truss for reducing self-weight, increasing load-carrying capacity com...
Journal of Construction Engineering, Management & Innovation
This paper presents a study of the parametric variability of post-tensioned concrete box-girder p... more This paper presents a study of the parametric variability of post-tensioned concrete box-girder pedestrian bridges. SAMO2 algorithm is used for the parametric study. This algorithm combines SA with a mutation operator, to find the economic solutions. A span-length parametric study analyzes the characteristics for the best design of a three-span deck in which the main span ranges from 30 to 60 m. The depth and the number of strands were adjusted according to span length, while the thickness of the slabs presented the same optimum values in all cases. Results show that the amount of steel and volume of concrete per square meter of deck shows a good correlation with the main span length. This study demonstrates that by increasing the main span length by one meter, the total cost per square meter of the deck increases by 6.38 euros on average. Thus, this paper shows the relationship between the span length and geometrical and steel variables to produce and build a cost-efficient pedestrian bridge.
This paper deals with optimizing embedded carbon dioxide (CO2) emissions using surrogate modeling... more This paper deals with optimizing embedded carbon dioxide (CO2) emissions using surrogate modeling, whether it is the deck of a post-tensioned cast-in-place concrete slab bridge or any other design structure. The main contribution of this proposal is that it allows optimizing structures methodically and sequentially. The approach presents two sequential phases of optimization, the first one of diversification and the second one of intensification of the search for optimums. Finally, with the amount of CO2 emissions and the differentiating characteristics of each design, a heuristic optimization based on a Kriging metamodel is performed. An optimized solution with lower emissions than the analyzed sample is obtained. If CO2 emissions were to be reduced, design recommendations would be to use slendernesses as high as possible, in the range of 1/30, which implies a more significant amount of passive reinforcement. This increase in passive reinforcement is compensated by reducing the mea...
At present, reducing the impact of the construction industry on the environment is the key to ach... more At present, reducing the impact of the construction industry on the environment is the key to achieving sustainable development. Countries all over the world are using software systems for bridge environmental impact assessment. However, due to the complexity and discreteness of environmental factors in the construction industry, they are difficult to update and determine quickly, and there is a phenomenon of data missing in the database. Most of the lost data are optimized by Monte Carlo simulation, which greatly reduces the reliability and accuracy of the research results. This paper uses Bayesian advanced fuzzy mathematics theory to solve this problem. In the research, a Bayesian fuzzy mathematics evaluation and a multi-level sensitivity priority discrimination model are established, and the weights and membership degrees of influencing factors were defined to achieve comprehensive coverage of influencing factors. With the support of theoretical modelling, software analysis and f...
This paper deals with the seismic column design of 35 elevated RC water storage tanks. Tanks comp... more This paper deals with the seismic column design of 35 elevated RC water storage tanks. Tanks comprise a top conic trunk reservoir, a column with variable hollow square cross-sections, and a shallow foundation on a sand layer. The five-column heights considered are 20, 25, 30, 35, and 40 m. The five tanks are subjected to seven degrees of seismic loading characterized by the reference peak ground acceleration in Eurocode 8. The elevated tanks are designed against the full prescriptions of Eurocode 2, Eurocode 8, and the Spaniard Structural Code of Practice. This includes variable loads for seismicity, wind, snow, etc., together with the action of self-weight and dead loads. The optimization design method considered is a variant of the old bachelor algorithm, an adaptive threshold acceptance method with a neighborhood move based on the mutation operator from genetic algorithms. Column results show the high nonlinearity of the problem since the horizontal seismic forces depend on the r...
The aim of this paper is to establish an international framework for sustainable project manageme... more The aim of this paper is to establish an international framework for sustainable project management in engineering, to make up the lack of research in this field, and to propose a scientific theoretical basis for the establishment of a new project management system. The article adopts literature review, mathematical programming algorithm and case study as the research method. The literature review applied the visual clustering research method and analyzed the results of 21-year research in this field. As a result, the project management system was found to have defects and deficiencies. A mathematical model was established to analyze the composition and elements of the optimized international project management system. The case study research selected large bridges for analysis and verified the superiority and practicability of the theoretical system. Thus, the goal of sustainable development of bridges was achieved. The value of this re-search lies in establishing a comprehensive i...
This paper deals with a short postgraduate course in automated design and economic optimization o... more This paper deals with a short postgraduate course in automated design and economic optimization of prestressed concrete bridges typically used in public road construction. The course forms part of a recent MSc course in Concrete Engineering which has started in October 2007. The course is concerned first with the basic heuristic algorithms for structural optimization, such as genetic algorithms, ant colonies, simulated annealing, tabu search, threshold acceptance, particle swarm optimization, neural networks, etc. And it then moves to the application of such algorithms to the practical design of real concrete structures such as walls, road portal and box frames, building frames, vaults, bridge piers, abutments and decks. Two design cases are presented. Simulated annealing (SA) is firstly applied to a prestressed concrete precast beam of 30-30 meters of longitudinal spans and 12.00 m of width. The beam has a double U-shape cross-section with beam spacing of 6 m. This example has 59 discrete design variables for the geometry of the beam and the slab, materials in the two elements and active and passive reinforcement. The SA method indicates savings of about 5% with respect to a traditional design. The second type of structure analysed is a 30-30 m prestressed concrete road bridge deck. This example has 27 discrete variables. Threshold accepting method (TA) indicates savings of about 7.5% with respect to the design based on the experience of the bridge designers. Finally, case studies indicate that heuristic optimization is a forthcoming option for improving the design costs of real prestressed bridge decks.
Document downloaded from: This paper must be cited as: The final publication is available at Copy... more Document downloaded from: This paper must be cited as: The final publication is available at Copyright
This paper presents one approach to the analysis and design of post-tensioned cast-in-place concr... more This paper presents one approach to the analysis and design of post-tensioned cast-in-place concrete slab bridge decks. A Simulated Annealing algorithm is applied to two objective functions: (i) the economic cost; and (ii) the embodied energy at different stages of production materials, transport, and construction. The problem involved 33 discrete design variables: five geometrical ones dealing with the thickness of the slab, the inner and exterior web width, and two flange thicknesses; concrete type; prestressing cables, and 26 variables for the reinforcement set-up. The comparison of the results obtained shows two different optimum families, which indicates that the traditional criteria of economic optimization leads to inefficient designs considering the embodied energy. The results indicate that the objectives are not competing functions, and that optimum energy designs are close to the optimum cost designs. The analysis also showed that the savings of each kW h of energy consum...
This paper describes a methodology to design reinfo rced concrete (RC) cantilever earth-retaining... more This paper describes a methodology to design reinfo rced concrete (RC) cantilever earth-retaining walls typically used in road construction based on minimum embedded CO2 emissions. The traditional approach to design does not fully optimize the use of materials. However, s t uctural optimization methods are a clear alternat ive to designs based only on experience. Here, the design involves optimization by a simulated annealing (SA) algorit hm applied to two objective functions, namely the embedded CO 2 emissions and the economic cost of reinforced conc rete walls. The formulation of the problem includes 20 d esign variables: four geometrical ones dealing with the thickness of the kerb and the footing, as well as t he toe and the heel lengths; four material types; a nd 12 variables for the reinforcement set-up. All the structural co nstraints have been imposed using Spanish codes, as well as habitual recommendations in this type of projects. Results from the SA algorithm application i...
This paper deals with the economic optimization of reinforced concrete walls, portal and box fram... more This paper deals with the economic optimization of reinforced concrete walls, portal and box frame structures typically used in road construction. It shows the efficiency of heuristic optimization by the simulated annealing algorithm. The evaluation of solutions follows the Spanish Code for structural concrete. Stress resultants and envelopes of framed structures are computed by an external finite element program. Design loads are in accordance with the national IAP Code for road bridges. The algorithm is first applied to RC retaining walls with 26 continuous design variables of geometry, materials and reinforcement. Results on this topic show the importance of limiting the deflection of walls. No restriction leads to slender solutions with deflections of up to 1/40 the height of the wall. Such elements are unfeasible and, hence, a limitation of 1/150 of the height is adopted for the design of these structures. The second structure analysed is a 10 m horizontal span RC portal frame....
International Journal of Environmental Research and Public Health, 2020
Due to the rapid growth of the construction industry’s global environmental impact, especially th... more Due to the rapid growth of the construction industry’s global environmental impact, especially the environmental impact contribution of bridge structures, it is necessary to study the detailed environmental impact of bridges at each stage of the full life cycle, which can provide optimal data support for sustainable development analysis. In this work, the environmental impact case of a three-tower cable-stayed bridge was analyzed through openLCA software, and more than 23,680 groups of data were analyzed using Markov chain and other research methods. It was concluded that the cable-stayed bridge contributed the most to the global warming potential value, which was mainly concentrated in the operation and maintenance phases. The conclusion shows that controlling the exhaust pollution of passing vehicles and improving the durability of building materials were the key to reducing carbon contribution and are also important directions for future research.
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