Civil engineering infrastructures journal, Oct 1, 2011
Building industry is one of the most energy consuming parts of the developed and developing count... more Building industry is one of the most energy consuming parts of the developed and developing countries. Cooling, heating and ventilating systems devote a great amount of this consumption so studying natural ventilation systems have become more important in order to improve their performance. In this paper, air flow has modeled by a computational fluid dynamic model with finite volume method in solar chimney as a new kind of natural ventilation system and in a combined system with Baadgir. For this reason, different turbulent models have been compared by a valid statistical test in order to find a suitable turbulent model in these systems and at the end a ke-RNG model has been selected. Also the effect of increasing height, span width and thermal gradient of the walls on improvement of solar chimney’s performance have been studied by computing parameters like mass flow rate and mean velocity.
Periodica Polytechnica-civil Engineering, Jun 26, 2023
Precast Concrete Construction (PCC) is a famous method in construction industry due to its differ... more Precast Concrete Construction (PCC) is a famous method in construction industry due to its different advantages. Nevertheless, this method has several discontinuous processes and they can enhance various uncertainty safety-quality issues. In this system, Building Information Modeling (BIM) technique plays a key role in managing of discontinuous processes to improve multidimensional safety and quality. Dimensionless parameters were used to evaluate the modified type of multidimensional BIM index (I MBIM) as the target index using the Modified Fuzzy Analytic Network Process (MFANP) method. In fact, the importance weight of input indices on the target was determined by the MFANP approach. The results of statistical analysis in verification step indicate that MFANP is well compatible with other approaches, so this developed method was considered as a reference point. The modified uncertainty Markov Chain Monte Carlo (MCMC) analysis was used for the validated method to determine the optimal high occurrence rate of I MBIM. The results demonstrate that a high percentage of occurrence frequency for I MBIM is in the range between 0.9 and 0.925. In this range, the mean optimal value of I MBIM as a management measure for multidimensional problems is 0.912. Stakeholders in PCC projects can use the proposed high occurrence range to assess the quality-safety of construction and make appropriate decisions.
Journal of numerical methods in civil engineering, Mar 1, 2021
In recent years, lightweight steel framed (LSF) structures are designed to resist fire, earthquak... more In recent years, lightweight steel framed (LSF) structures are designed to resist fire, earthquakes, and storm events. This system has entered the field of construction due to advantages of light members. Based on these advantages, such a system is also used for buildings with special importance. Structural health monitoring (SHM) implements a damage detection and characterization strategy for engineering structures. In the present study, a multiobjective numerical method for optimal sensor placement based on the combination of Modal Assurance Criteria (MAC) and maximum stress has been proposed. Genetic Algorithm (GA) was employed to determine the location of sensors on the structure based on the structural dynamic response of the LSF system. To show the efficiency of the proposed method, a very large irregular museum building, which was built by using LSF system, has been considered. To improve the proposed method, dominant frequencies are identified and the number of sensors is decreased using the Fourier Transform (FT) of the ground motions time history. Results show that the proposed method can provide the optimal sensor locations and remarkably reduce the number of required sensors and also improve their optimum location.
Corrigendum to “Health Monitoring of Storage Tanks Subject to Near-Field and Far-Field Earthquake... more Corrigendum to “Health Monitoring of Storage Tanks Subject to Near-Field and Far-Field Earthquakes” [Engineering Science & Technology, Volume 2 Issue 2 (2021) 116-130] https://doi.org/10.37256/est.222021640 Published online May 7, 2021. The authors regret they missed to one of the authors, Hamidreza Vosoughifar, whose contribution to this paper that could not be ignored. The correct authorship should be: Hossein Mirzaaghabeik, Rafael Holdorf Lopez, Marcos Souza Lenzi, Hamidreza Vosoughifar. The authors would like to apologize for the inconvenience caused.
Pacific Science Review A: Natural Science and Engineering, Nov 1, 2016
Lightweight steel framing (LSF) has been proposed as an economic and earthquake-resistant system.... more Lightweight steel framing (LSF) has been proposed as an economic and earthquake-resistant system. The tendency of mass constructors to use this system is due to it being a full industrial process. One of the systems that resist lateral load in cold-formed steel structures is the application of braces. Optimization and improvement of connections for these braces have been considered by experts in this field of research. In this paper, experimental studies and normalization and simulation by artificial neural network (ANN) were used. The results of the research have been applied to create a nonlinear relationship. All input and target data must be normalized and then simulation and training by a neural network can be performed. In this research, two layers have been used. One of these is a sigmoid layer. The results show that optimal connections in light weight steel framing systems have suitable plasticity, load capacity and nonlinear relations. Statistical analysis with SPSS software shows that there is no significant difference between the neural network and experimental results (P-Value > 0.05).
Pacific Science Review A: Natural Science and Engineering, Nov 1, 2015
The Lightweight Steel Framing (LSF) system has been proposed as an economical and earthquake resi... more The Lightweight Steel Framing (LSF) system has been proposed as an economical and earthquake resistant system. Due to the lightweight nature of LSF structures, the seismic performance of middle-rise buildings has been improved. Currently, various numerical-analytical methods have been proposed for seismic assessment of conventional structures. Providing a perfect seismic Health Safety Environment (HSE) index has always been regarded as one of the analytical passive points. In this research, an LSF building was selected as a case study for Finite Element (FE) modelling, in which non-linear time-history analyses were undertaken. Material properties were defined according to the performed experimental studies. A novel approach was presented for the seismic HSE index of LSF systems using the simultaneous incorporation of the non-linear analysis results and the correction coefficient describing the seismic geotechnical effects. The presented seismic HSE index accurately demonstrates the seismic performance of the LSF structures. Additionally, a two-layer perceptron Artificial Neural Network (ANN) was trained using the results of the FE model, and a non-linear relationship was obtained to predict the seismic damage index. Finally, the proposed seismic HSE index was validated using statistical analyses, indicating that the proposed method does not yield a significant difference compared to the ANN results.
In this paper, a n i t e volume scheme is used to discretize ow i n porous media. A numerical met... more In this paper, a n i t e volume scheme is used to discretize ow i n porous media. A numerical method for treating advection-dominated contaminant transport for ow of groundwater is described. This system combines the advantages of numerical discretization and the nite volume method (like local mass conservation). The equations are discretized using a nite volume approach. The resulting nonlinear di erential system is integrated in time using a solver. The conservation of energy (convection-di usion) equation is solved using a special method for reducing the oscillations induced by the standard nite volume method. Consequently, a mathematical model for multi-component ow transport in an anisotropic media is presented, which couples the equations for multi-component di usion and Darcy's law f o r o w i n a p o rous medium. Furthermore, application of an integrated matlab system in several studies has been provided. The integrated matlab system is based on open data formats and standards and may be used for many other application areas, especially where modeling in 2D and 3D is involved. Numerical simulations are performed to validate the model and investigate the e ect. The nal purpose of this paper is to discuss and compare the di erence between the nite volume scheme for uniform and for unstructured grids, which is shown to be less than 0.2 percent.
In this study, coupled method for simulation of flow pattern based on computational methods for f... more In this study, coupled method for simulation of flow pattern based on computational methods for fluid dynamics with optimization technique using genetic algorithms is presented to determine the optimal location and number of sensors in an enclosed residential complex parking in Tehran. The main objective of this research is costs reduction and maximum coverage with regard to distribution of existing concentrations in different scenarios. In this study, considering all the different scenarios for simulation of pollution distribution using CFD simulations has been challenging due to extent of parking and number of cars available. To solve this problem, some scenarios have been selected based on random method. Then, maximum concentrations of scenarios are chosen for performing optimization. CFD simulation outputs are inserted as input in the optimization model using genetic algorithm. The obtained results stated optimal number and location of sensors.
Purpose Lean management has been used in various constructions around the world for more than a q... more Purpose Lean management has been used in various constructions around the world for more than a quarter of a century, and it is an important factor in the construction of new projects. In relation to demolition management, only standards and codes and general principles of demolition of specific buildings were evaluated. The purpose of this study is providing relation between lean management on demolition processes of municipality buildings evaluated. Design/methodology/approach This study investigates the lean demolition of demolished and renovated buildings in a metropolitan area that can be extended to all cities. In the first stage, the effective factors in the demolition of the building based on lean management were identified through a valid questionnaire based on the valid Delphi approach. Social, economic and environmental considerations were considered in designing the appropriate questionnaire. Findings The modified approach between the fuzzy method and partial least squar...
Civil engineering infrastructures journal, Oct 1, 2011
Building industry is one of the most energy consuming parts of the developed and developing count... more Building industry is one of the most energy consuming parts of the developed and developing countries. Cooling, heating and ventilating systems devote a great amount of this consumption so studying natural ventilation systems have become more important in order to improve their performance. In this paper, air flow has modeled by a computational fluid dynamic model with finite volume method in solar chimney as a new kind of natural ventilation system and in a combined system with Baadgir. For this reason, different turbulent models have been compared by a valid statistical test in order to find a suitable turbulent model in these systems and at the end a ke-RNG model has been selected. Also the effect of increasing height, span width and thermal gradient of the walls on improvement of solar chimney’s performance have been studied by computing parameters like mass flow rate and mean velocity.
Periodica Polytechnica-civil Engineering, Jun 26, 2023
Precast Concrete Construction (PCC) is a famous method in construction industry due to its differ... more Precast Concrete Construction (PCC) is a famous method in construction industry due to its different advantages. Nevertheless, this method has several discontinuous processes and they can enhance various uncertainty safety-quality issues. In this system, Building Information Modeling (BIM) technique plays a key role in managing of discontinuous processes to improve multidimensional safety and quality. Dimensionless parameters were used to evaluate the modified type of multidimensional BIM index (I MBIM) as the target index using the Modified Fuzzy Analytic Network Process (MFANP) method. In fact, the importance weight of input indices on the target was determined by the MFANP approach. The results of statistical analysis in verification step indicate that MFANP is well compatible with other approaches, so this developed method was considered as a reference point. The modified uncertainty Markov Chain Monte Carlo (MCMC) analysis was used for the validated method to determine the optimal high occurrence rate of I MBIM. The results demonstrate that a high percentage of occurrence frequency for I MBIM is in the range between 0.9 and 0.925. In this range, the mean optimal value of I MBIM as a management measure for multidimensional problems is 0.912. Stakeholders in PCC projects can use the proposed high occurrence range to assess the quality-safety of construction and make appropriate decisions.
Journal of numerical methods in civil engineering, Mar 1, 2021
In recent years, lightweight steel framed (LSF) structures are designed to resist fire, earthquak... more In recent years, lightweight steel framed (LSF) structures are designed to resist fire, earthquakes, and storm events. This system has entered the field of construction due to advantages of light members. Based on these advantages, such a system is also used for buildings with special importance. Structural health monitoring (SHM) implements a damage detection and characterization strategy for engineering structures. In the present study, a multiobjective numerical method for optimal sensor placement based on the combination of Modal Assurance Criteria (MAC) and maximum stress has been proposed. Genetic Algorithm (GA) was employed to determine the location of sensors on the structure based on the structural dynamic response of the LSF system. To show the efficiency of the proposed method, a very large irregular museum building, which was built by using LSF system, has been considered. To improve the proposed method, dominant frequencies are identified and the number of sensors is decreased using the Fourier Transform (FT) of the ground motions time history. Results show that the proposed method can provide the optimal sensor locations and remarkably reduce the number of required sensors and also improve their optimum location.
Corrigendum to “Health Monitoring of Storage Tanks Subject to Near-Field and Far-Field Earthquake... more Corrigendum to “Health Monitoring of Storage Tanks Subject to Near-Field and Far-Field Earthquakes” [Engineering Science & Technology, Volume 2 Issue 2 (2021) 116-130] https://doi.org/10.37256/est.222021640 Published online May 7, 2021. The authors regret they missed to one of the authors, Hamidreza Vosoughifar, whose contribution to this paper that could not be ignored. The correct authorship should be: Hossein Mirzaaghabeik, Rafael Holdorf Lopez, Marcos Souza Lenzi, Hamidreza Vosoughifar. The authors would like to apologize for the inconvenience caused.
Pacific Science Review A: Natural Science and Engineering, Nov 1, 2016
Lightweight steel framing (LSF) has been proposed as an economic and earthquake-resistant system.... more Lightweight steel framing (LSF) has been proposed as an economic and earthquake-resistant system. The tendency of mass constructors to use this system is due to it being a full industrial process. One of the systems that resist lateral load in cold-formed steel structures is the application of braces. Optimization and improvement of connections for these braces have been considered by experts in this field of research. In this paper, experimental studies and normalization and simulation by artificial neural network (ANN) were used. The results of the research have been applied to create a nonlinear relationship. All input and target data must be normalized and then simulation and training by a neural network can be performed. In this research, two layers have been used. One of these is a sigmoid layer. The results show that optimal connections in light weight steel framing systems have suitable plasticity, load capacity and nonlinear relations. Statistical analysis with SPSS software shows that there is no significant difference between the neural network and experimental results (P-Value > 0.05).
Pacific Science Review A: Natural Science and Engineering, Nov 1, 2015
The Lightweight Steel Framing (LSF) system has been proposed as an economical and earthquake resi... more The Lightweight Steel Framing (LSF) system has been proposed as an economical and earthquake resistant system. Due to the lightweight nature of LSF structures, the seismic performance of middle-rise buildings has been improved. Currently, various numerical-analytical methods have been proposed for seismic assessment of conventional structures. Providing a perfect seismic Health Safety Environment (HSE) index has always been regarded as one of the analytical passive points. In this research, an LSF building was selected as a case study for Finite Element (FE) modelling, in which non-linear time-history analyses were undertaken. Material properties were defined according to the performed experimental studies. A novel approach was presented for the seismic HSE index of LSF systems using the simultaneous incorporation of the non-linear analysis results and the correction coefficient describing the seismic geotechnical effects. The presented seismic HSE index accurately demonstrates the seismic performance of the LSF structures. Additionally, a two-layer perceptron Artificial Neural Network (ANN) was trained using the results of the FE model, and a non-linear relationship was obtained to predict the seismic damage index. Finally, the proposed seismic HSE index was validated using statistical analyses, indicating that the proposed method does not yield a significant difference compared to the ANN results.
In this paper, a n i t e volume scheme is used to discretize ow i n porous media. A numerical met... more In this paper, a n i t e volume scheme is used to discretize ow i n porous media. A numerical method for treating advection-dominated contaminant transport for ow of groundwater is described. This system combines the advantages of numerical discretization and the nite volume method (like local mass conservation). The equations are discretized using a nite volume approach. The resulting nonlinear di erential system is integrated in time using a solver. The conservation of energy (convection-di usion) equation is solved using a special method for reducing the oscillations induced by the standard nite volume method. Consequently, a mathematical model for multi-component ow transport in an anisotropic media is presented, which couples the equations for multi-component di usion and Darcy's law f o r o w i n a p o rous medium. Furthermore, application of an integrated matlab system in several studies has been provided. The integrated matlab system is based on open data formats and standards and may be used for many other application areas, especially where modeling in 2D and 3D is involved. Numerical simulations are performed to validate the model and investigate the e ect. The nal purpose of this paper is to discuss and compare the di erence between the nite volume scheme for uniform and for unstructured grids, which is shown to be less than 0.2 percent.
In this study, coupled method for simulation of flow pattern based on computational methods for f... more In this study, coupled method for simulation of flow pattern based on computational methods for fluid dynamics with optimization technique using genetic algorithms is presented to determine the optimal location and number of sensors in an enclosed residential complex parking in Tehran. The main objective of this research is costs reduction and maximum coverage with regard to distribution of existing concentrations in different scenarios. In this study, considering all the different scenarios for simulation of pollution distribution using CFD simulations has been challenging due to extent of parking and number of cars available. To solve this problem, some scenarios have been selected based on random method. Then, maximum concentrations of scenarios are chosen for performing optimization. CFD simulation outputs are inserted as input in the optimization model using genetic algorithm. The obtained results stated optimal number and location of sensors.
Purpose Lean management has been used in various constructions around the world for more than a q... more Purpose Lean management has been used in various constructions around the world for more than a quarter of a century, and it is an important factor in the construction of new projects. In relation to demolition management, only standards and codes and general principles of demolition of specific buildings were evaluated. The purpose of this study is providing relation between lean management on demolition processes of municipality buildings evaluated. Design/methodology/approach This study investigates the lean demolition of demolished and renovated buildings in a metropolitan area that can be extended to all cities. In the first stage, the effective factors in the demolition of the building based on lean management were identified through a valid questionnaire based on the valid Delphi approach. Social, economic and environmental considerations were considered in designing the appropriate questionnaire. Findings The modified approach between the fuzzy method and partial least squar...
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