Pub Date : 2021-04-12DOI: 10.11648/J.AJCE.20210902.11
Zhang Xin, Zhang Xiangping, Wang Zhang, Lang Min, Zhao Suzhi, Duan Yuxiang, Sun Jinshan
The elastoplastic analysis of the surrounding rock of a circular tunnel is a very classic rock and soil mechanics problem. Previous scholars usually studied the situation under axisymmetric load, and they usually did not take the non-axisymmetric load distribution under the influence of ground stress and lateral pressure into account, which greatly affected its application in engineering practice. Approximate analytical solutions for calculating the plastic zone range, stress field and displacement field of the surrounding rock of a circular tunnel are inseparable from the consideration of the strength reduction and volumetric dilatancy characteristics of the rock material. The elastic-softening-residual plastic triple linear stress-strain model and the Mohr-Coulumb failure criterion are involved. The approximate analytical solutions of the residual stress field, strain field, displacement field and radius of the plastic zone in the elastic zone, plastic softening zone and surrounding plastic zone of the circular tunnel surrounding rock under axisymmetric load are deduced. The analytical solutions are valid only when the plastic zone is large and the lateral pressure coefficients 1≤λ<3. The approximate analytical method is close to the calculation result of finite element method and can replace the finite element method to carry out simple elastic-plastic analysis of surrounding rock.
{"title":"Analytical Elastoplastic Solutions for Deep-buried Circular Tunnels Under Asymmetric Load","authors":"Zhang Xin, Zhang Xiangping, Wang Zhang, Lang Min, Zhao Suzhi, Duan Yuxiang, Sun Jinshan","doi":"10.11648/J.AJCE.20210902.11","DOIUrl":"https://doi.org/10.11648/J.AJCE.20210902.11","url":null,"abstract":"The elastoplastic analysis of the surrounding rock of a circular tunnel is a very classic rock and soil mechanics problem. Previous scholars usually studied the situation under axisymmetric load, and they usually did not take the non-axisymmetric load distribution under the influence of ground stress and lateral pressure into account, which greatly affected its application in engineering practice. Approximate analytical solutions for calculating the plastic zone range, stress field and displacement field of the surrounding rock of a circular tunnel are inseparable from the consideration of the strength reduction and volumetric dilatancy characteristics of the rock material. The elastic-softening-residual plastic triple linear stress-strain model and the Mohr-Coulumb failure criterion are involved. The approximate analytical solutions of the residual stress field, strain field, displacement field and radius of the plastic zone in the elastic zone, plastic softening zone and surrounding plastic zone of the circular tunnel surrounding rock under axisymmetric load are deduced. The analytical solutions are valid only when the plastic zone is large and the lateral pressure coefficients 1≤λ<3. The approximate analytical method is close to the calculation result of finite element method and can replace the finite element method to carry out simple elastic-plastic analysis of surrounding rock.","PeriodicalId":7606,"journal":{"name":"American Journal of Civil Engineering","volume":"50 1","pages":"31"},"PeriodicalIF":0.0,"publicationDate":"2021-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81510618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-26DOI: 10.11648/J.AJCE.20210901.13
Hyeok-jung Kim, Namwook Kim
Cracks and voids of concrete cause the loss of durability. When the cracks reach to the surface of reinforced concrete structures, they can repair by various methods, but there are no effective repairing methods for latent faults or micro-cracks caused by load repetition because they cannot detect by surface state. In this study, we examined the presence or absence of self-repair performance of concrete mixed with the admixture using the coating material for repair, which has been used for a long time. Thus, the basic characteristics of concrete mixed with admixture were identified and self-repair performance was confirmed through experiments. As a result of considering the recovery of the strength of damaged concrete, concrete mixed with a surface coating agent showed a greater recovery effect than concrete mixed with non-mixed concrete. This effect is greater with the age of the damaged material. This shows that even if the repair coating material is mixed as an admixture, the crystal proliferation effect is maintained, and it is confirmed that the concrete mixed with the admixture has self-repairing performance.
{"title":"Evaluation on the Strength Recovery Rate of Concrete Using Surface Coating Agent","authors":"Hyeok-jung Kim, Namwook Kim","doi":"10.11648/J.AJCE.20210901.13","DOIUrl":"https://doi.org/10.11648/J.AJCE.20210901.13","url":null,"abstract":"Cracks and voids of concrete cause the loss of durability. When the cracks reach to the surface of reinforced concrete structures, they can repair by various methods, but there are no effective repairing methods for latent faults or micro-cracks caused by load repetition because they cannot detect by surface state. In this study, we examined the presence or absence of self-repair performance of concrete mixed with the admixture using the coating material for repair, which has been used for a long time. Thus, the basic characteristics of concrete mixed with admixture were identified and self-repair performance was confirmed through experiments. As a result of considering the recovery of the strength of damaged concrete, concrete mixed with a surface coating agent showed a greater recovery effect than concrete mixed with non-mixed concrete. This effect is greater with the age of the damaged material. This shows that even if the repair coating material is mixed as an admixture, the crystal proliferation effect is maintained, and it is confirmed that the concrete mixed with the admixture has self-repairing performance.","PeriodicalId":7606,"journal":{"name":"American Journal of Civil Engineering","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75238933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-26DOI: 10.11648/J.AJCE.20210901.14
Teimuraz Kikava, L. Dolidze
To ensure uniform settlement of buildings and structures erected on a weak and heterogeneous soils, reinforced concrete foundations are designed from cross beams, or solid slabs. Currently, cross foundation beams and solid slabs are widely used in construction, like in the construction of high-rise buildings and many other engineering structures. In cross beams, at their intersection with an increase in load and stiffness, especially with an asymmetric load, in addition to bending moments and shear forces, the torques reaching large values can also occur, which are often not taken into account. The torques arisen at the knots of the crossed foundations may, in some cases, have a significant effect on their operation, for example, if the torques reach important values, then additional reinforcement must be placed in the foundations by stipulating the pressures arisen from them. For the correct selection of reinforcement, it is necessary to know the values of not only the bending moments, but also the torques arisen in the constructions. The existing methods of calculation often consider and calculate the crossed foundations as the constructions lying on a linearly deformable base. Besides most of them do not take into account the influence of torques. The methods of calculating the crossed foundations have been worked out by the author, by stipulating effect of bending moments on their working. There are given the formulas to calculate the bending moments, the system of equations is drawn up for linear and angular movements to define the unknown forces arisen at the knots of crossing the foundation beams. After determining these unknown forces, each beam is considered and calculated as a separate one, lying on a linearly deformable foundation.
{"title":"The Analysis of Crossed Foundation Beams Lying on the Soil Base","authors":"Teimuraz Kikava, L. Dolidze","doi":"10.11648/J.AJCE.20210901.14","DOIUrl":"https://doi.org/10.11648/J.AJCE.20210901.14","url":null,"abstract":"To ensure uniform settlement of buildings and structures erected on a weak and heterogeneous soils, reinforced concrete foundations are designed from cross beams, or solid slabs. Currently, cross foundation beams and solid slabs are widely used in construction, like in the construction of high-rise buildings and many other engineering structures. In cross beams, at their intersection with an increase in load and stiffness, especially with an asymmetric load, in addition to bending moments and shear forces, the torques reaching large values can also occur, which are often not taken into account. The torques arisen at the knots of the crossed foundations may, in some cases, have a significant effect on their operation, for example, if the torques reach important values, then additional reinforcement must be placed in the foundations by stipulating the pressures arisen from them. For the correct selection of reinforcement, it is necessary to know the values of not only the bending moments, but also the torques arisen in the constructions. The existing methods of calculation often consider and calculate the crossed foundations as the constructions lying on a linearly deformable base. Besides most of them do not take into account the influence of torques. The methods of calculating the crossed foundations have been worked out by the author, by stipulating effect of bending moments on their working. There are given the formulas to calculate the bending moments, the system of equations is drawn up for linear and angular movements to define the unknown forces arisen at the knots of crossing the foundation beams. After determining these unknown forces, each beam is considered and calculated as a separate one, lying on a linearly deformable foundation.","PeriodicalId":7606,"journal":{"name":"American Journal of Civil Engineering","volume":"1 1","pages":"25"},"PeriodicalIF":0.0,"publicationDate":"2021-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82260973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
As a nondestructive detecting method, ultrasonic detection has been widely adopted in concrete structure detections. This approach would not damage the structural integrity, and could fulfill most of the detecting requirements of various concrete structures. However, for mass concrete and complicated concrete structural elements, there are still many problems of detection to be solved, such as the operating position of detection could not be achieved easily for technicians, especially in some narrow spaces, or the volume of elements might be quite large so that the detecting distance is far beyond the effective detecting distance of traditional transducers. After researching the technical performances of traditional ultrasonic transducers and ultrasonic detecting method, a brand new type of ultrasonic transducer adopted spherical piezoelectric ceramic chips has been developed. The transducer could be embedded inside concrete structure, and motivate or receive ultrasonic signal in all directions pair with external or internal transducers. Testing with the embedded transducers would not be limited by on-site conditions or other enviorenmental conditions. The transducer could be used in realtime systems for monitoring or detecting internal compactness situation of concrete elements. The technical characteristics of spherical transducer have been verified by a series of experiments in laboratory. Moreover, the detecting method with spherical transducer has been proposed, which could be used in the inspection for mass concrete and complicated structural concrete elements. Meanwhile, the appropriate technical schemes for reactor containment of nuclear power plant have been designed and has already been applied in nuclear power plant.
{"title":"Research for the Detecting Method of Concrete Structure Internal Defects with Spherical Embedded Ultrasonic Transducer","authors":"Zhang Xingbin, Fang Sha, HuaWei Rong, Wu Jingshu, Zhao Guanqiao","doi":"10.11648/J.AJCE.20210901.12","DOIUrl":"https://doi.org/10.11648/J.AJCE.20210901.12","url":null,"abstract":"As a nondestructive detecting method, ultrasonic detection has been widely adopted in concrete structure detections. This approach would not damage the structural integrity, and could fulfill most of the detecting requirements of various concrete structures. However, for mass concrete and complicated concrete structural elements, there are still many problems of detection to be solved, such as the operating position of detection could not be achieved easily for technicians, especially in some narrow spaces, or the volume of elements might be quite large so that the detecting distance is far beyond the effective detecting distance of traditional transducers. After researching the technical performances of traditional ultrasonic transducers and ultrasonic detecting method, a brand new type of ultrasonic transducer adopted spherical piezoelectric ceramic chips has been developed. The transducer could be embedded inside concrete structure, and motivate or receive ultrasonic signal in all directions pair with external or internal transducers. Testing with the embedded transducers would not be limited by on-site conditions or other enviorenmental conditions. The transducer could be used in realtime systems for monitoring or detecting internal compactness situation of concrete elements. The technical characteristics of spherical transducer have been verified by a series of experiments in laboratory. Moreover, the detecting method with spherical transducer has been proposed, which could be used in the inspection for mass concrete and complicated structural concrete elements. Meanwhile, the appropriate technical schemes for reactor containment of nuclear power plant have been designed and has already been applied in nuclear power plant.","PeriodicalId":7606,"journal":{"name":"American Journal of Civil Engineering","volume":"5 1","pages":"11"},"PeriodicalIF":0.0,"publicationDate":"2021-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79402386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-22DOI: 10.11648/J.AJCE.20210901.11
Shan-e-hyder Soomro, Cai-hong Hu, M. Babar, Mairaj Hyder Alias Aamir
In understanding the hydraulic characteristics of river system flow, the hydraulic simulation models are essential tools. The suitable value of Manning’s roughness coefficient “n” is chosen through method of calibration; i.e., the value which reproduces observed data to an acceptable accuracy. In the present study, the unsteady flow model HEC-RAS is applied to Rohri Canal (upstream Rohri) to estimate value of manning’s coefficient through the procedure. Through a series of systematic. Studies to identify the n values in a hypothetical open channel and a natural stream stretch, several identification procedures based on unconstrained and constrained minimizations are analyzed. However, the decision on what value to adopt is a complex task, especially when dealing with natural water courses due to the various factors that affect this coefficient ‘n’. The data was collected in the period of January (2010) to December (2011), and divided equally into two sets. The first set is for calibration purpose, estimation of (n) and the second set for the verification process of testing the model with actual data to establish its predictability accuracy. Graphical and statistical approaches were used for model calibration and verification. Results show that the manning’s roughness coefficient “n” for Rohri Canal which shows good agreement between observed and computed hydrograph is 0.042.
{"title":"Estimation of Manning’s Roughness Coefficient Through Calibration Using HEC-RAS Model: A Case Study of Rohri Canal, Pakistan","authors":"Shan-e-hyder Soomro, Cai-hong Hu, M. Babar, Mairaj Hyder Alias Aamir","doi":"10.11648/J.AJCE.20210901.11","DOIUrl":"https://doi.org/10.11648/J.AJCE.20210901.11","url":null,"abstract":"In understanding the hydraulic characteristics of river system flow, the hydraulic simulation models are essential tools. The suitable value of Manning’s roughness coefficient “n” is chosen through method of calibration; i.e., the value which reproduces observed data to an acceptable accuracy. In the present study, the unsteady flow model HEC-RAS is applied to Rohri Canal (upstream Rohri) to estimate value of manning’s coefficient through the procedure. Through a series of systematic. Studies to identify the n values in a hypothetical open channel and a natural stream stretch, several identification procedures based on unconstrained and constrained minimizations are analyzed. However, the decision on what value to adopt is a complex task, especially when dealing with natural water courses due to the various factors that affect this coefficient ‘n’. The data was collected in the period of January (2010) to December (2011), and divided equally into two sets. The first set is for calibration purpose, estimation of (n) and the second set for the verification process of testing the model with actual data to establish its predictability accuracy. Graphical and statistical approaches were used for model calibration and verification. Results show that the manning’s roughness coefficient “n” for Rohri Canal which shows good agreement between observed and computed hydrograph is 0.042.","PeriodicalId":7606,"journal":{"name":"American Journal of Civil Engineering","volume":"1 1","pages":"1"},"PeriodicalIF":0.0,"publicationDate":"2021-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89690976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.11648/j.ajce.20210906.15
Kidanemariam Sileshi
: The construction sectors project implementation is realized by which it undergoes many problems, difficulties and highly complicated process from inceptions to completion. Ethiopia’s construction projects are highly subjected to cost and schedule overrun and developing success factors as early as possible is a pressing issue. The objective of this paper is to determine the most significant success factors of mixed use building construction project using quantitative statistical method. Data collected from different respondents through questionaries’ analyzed using RII. Based on the RII result General Project management Related success factors becomes the leading than other success factor group. This group is more general and shared by all stakeholder and considered in each phase from initiation to the end. Followed by Environment, Client, Consultant and contractor related major success factor groups respectively. All the aggregated list of success factor has a significant factor for the success. Most important success factors are: Lessons learned from previous project, having qualified and specialized personnel, clearly defining project scope, Consistency of currency price & stability of national economy, Material and equipment availability, Conducting On-job research, Consultant commitment to ensure construction work. Identifying success factors with respect to each stakeholders and phases will benefit a lot to do their best at each stage of the project. Learning from previous work, having qualified and specialized personnel and defining scope clearly should have to be the core of project participant at each stage of construction project to accomplish successfully.
{"title":"Success Factors of Mixed-Use Building Construction Project: A Case of Arada Sub-City, Addis Ababa","authors":"Kidanemariam Sileshi","doi":"10.11648/j.ajce.20210906.15","DOIUrl":"https://doi.org/10.11648/j.ajce.20210906.15","url":null,"abstract":": The construction sectors project implementation is realized by which it undergoes many problems, difficulties and highly complicated process from inceptions to completion. Ethiopia’s construction projects are highly subjected to cost and schedule overrun and developing success factors as early as possible is a pressing issue. The objective of this paper is to determine the most significant success factors of mixed use building construction project using quantitative statistical method. Data collected from different respondents through questionaries’ analyzed using RII. Based on the RII result General Project management Related success factors becomes the leading than other success factor group. This group is more general and shared by all stakeholder and considered in each phase from initiation to the end. Followed by Environment, Client, Consultant and contractor related major success factor groups respectively. All the aggregated list of success factor has a significant factor for the success. Most important success factors are: Lessons learned from previous project, having qualified and specialized personnel, clearly defining project scope, Consistency of currency price & stability of national economy, Material and equipment availability, Conducting On-job research, Consultant commitment to ensure construction work. Identifying success factors with respect to each stakeholders and phases will benefit a lot to do their best at each stage of the project. Learning from previous work, having qualified and specialized personnel and defining scope clearly should have to be the core of project participant at each stage of construction project to accomplish successfully.","PeriodicalId":7606,"journal":{"name":"American Journal of Civil Engineering","volume":"39 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90877119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.11648/j.ajce.20210905.14
Jianlong Zhao, Yanfeng Li, Jin-Lan Wu
: When a fire occurs in a ventilation confined compartment, the fire gradually weakened and finally self-extinguishes due to the oxygen concentration in the compartment will decrease and eventually below the flammable limit. Meanwhile, a large amount of high-temperature combustible substance is generated in the compartment during this period by pyrolysis or evaporation of fuel. When the compartment ventilation is improved, such as the window is broken, fresh air flows into the compartment and mix with high-temperature combustible substances and lead to the fire occurs again. This special phenomenon during the development of a compartment fire is called backdraft. In addition, a large amount of high-temperature combustible substances is accumulated in the compartment before the backdraft occurs. Therefore, once a backdraft occurs, it always leads to a flashover, which means a fire has reached fully development stage and is out of control. Hence, a backdraft will lead to substantial finical loss and heavy casualties. To investigate the influence of compartment opening area on backdraft time, we conducted fire experiments of solid fuel in a reduced-scale compartment. The temperature and the gas concentration in the compartment were measured by thermocouples and gas analyzer, respectively. Results show that the backdraft time of solid fuel would become shorter as the opening area of the compartment increases. The results of this research could improve the understanding of the backdraft mechanism of solid fuel and provide a strategy to delay or even restrain the backdraft occurrence for firefighters.
{"title":"Effect of the Opening Area of Compartment on the Backdraft Time","authors":"Jianlong Zhao, Yanfeng Li, Jin-Lan Wu","doi":"10.11648/j.ajce.20210905.14","DOIUrl":"https://doi.org/10.11648/j.ajce.20210905.14","url":null,"abstract":": When a fire occurs in a ventilation confined compartment, the fire gradually weakened and finally self-extinguishes due to the oxygen concentration in the compartment will decrease and eventually below the flammable limit. Meanwhile, a large amount of high-temperature combustible substance is generated in the compartment during this period by pyrolysis or evaporation of fuel. When the compartment ventilation is improved, such as the window is broken, fresh air flows into the compartment and mix with high-temperature combustible substances and lead to the fire occurs again. This special phenomenon during the development of a compartment fire is called backdraft. In addition, a large amount of high-temperature combustible substances is accumulated in the compartment before the backdraft occurs. Therefore, once a backdraft occurs, it always leads to a flashover, which means a fire has reached fully development stage and is out of control. Hence, a backdraft will lead to substantial finical loss and heavy casualties. To investigate the influence of compartment opening area on backdraft time, we conducted fire experiments of solid fuel in a reduced-scale compartment. The temperature and the gas concentration in the compartment were measured by thermocouples and gas analyzer, respectively. Results show that the backdraft time of solid fuel would become shorter as the opening area of the compartment increases. The results of this research could improve the understanding of the backdraft mechanism of solid fuel and provide a strategy to delay or even restrain the backdraft occurrence for firefighters.","PeriodicalId":7606,"journal":{"name":"American Journal of Civil Engineering","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85245270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.11648/j.ajce.20210904.12
Addisu Sherbeza Woldemariam
{"title":"Urban Land Use Analysis and Policy Review of Ethiopia with Special Reference to Micro and Small Enterprise Development Initiative of Hawassa City","authors":"Addisu Sherbeza Woldemariam","doi":"10.11648/j.ajce.20210904.12","DOIUrl":"https://doi.org/10.11648/j.ajce.20210904.12","url":null,"abstract":"","PeriodicalId":7606,"journal":{"name":"American Journal of Civil Engineering","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82272619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.11648/j.ajce.20210906.13
Nulu Reddeppa, B. Jayarami Reddy, H. Sudarsana Rao
: Optimal structural design involves dealing with three main factors visibly cross-sectional properties of the members, topology and configuration and meeting the intended functional requirements. Most of the traditional optimization techniques are based on the mathematical programming techniques, which assume that the variables are continuous, but whereas the process of structural design is generally characterized by finite often large numbers of variables of discrete in nature. Genetic Algorithm is the technique which can be used efficiently for the design optimization of the structure with discrete variables. From the study on previous work done on GA’s application in civil engineering, it has been noticed that application of GA’s is not attempted in rotating machine foundations where there is scope for determining suitable optimum shape and member sizes to achieve a well-tuned foundation. Dynamic design of machine foundation involves broad criterion such as foundation natural frequency shall be away from the machine operating frequency and foundation displacement amplitudes shall be well within the specified allowable limits. The above criterion largely depends on design factors such as size of members, shape of the foundations, concrete grade and soil characters. Presently obtaining a best suitable solution meeting the frequency and amplitude criteria by varying above four design factors involves many manual trails. This involves lot of computer and human efforts to try various combinations to arrive at the solution. Considerable resources and time need to be spent on arriving a suitable solution. Yet the solution so arrived may not be an optimum solution. In this work, Genetic algorithms is applied for optimization of solution time and foundation volume for industrial medium and heavy rotating equipment foundations. Optimum solution is obtained with above variables by setting frequency as target criteria. The optimum solution obtained from Genetic Algorithms is further verified for its compliance to its intended functional parameters by means of finite element model study.
{"title":"Application of Genetic Algorithms to Optimization of Medium and Heavy Rotating Equipment Foundations","authors":"Nulu Reddeppa, B. Jayarami Reddy, H. Sudarsana Rao","doi":"10.11648/j.ajce.20210906.13","DOIUrl":"https://doi.org/10.11648/j.ajce.20210906.13","url":null,"abstract":": Optimal structural design involves dealing with three main factors visibly cross-sectional properties of the members, topology and configuration and meeting the intended functional requirements. Most of the traditional optimization techniques are based on the mathematical programming techniques, which assume that the variables are continuous, but whereas the process of structural design is generally characterized by finite often large numbers of variables of discrete in nature. Genetic Algorithm is the technique which can be used efficiently for the design optimization of the structure with discrete variables. From the study on previous work done on GA’s application in civil engineering, it has been noticed that application of GA’s is not attempted in rotating machine foundations where there is scope for determining suitable optimum shape and member sizes to achieve a well-tuned foundation. Dynamic design of machine foundation involves broad criterion such as foundation natural frequency shall be away from the machine operating frequency and foundation displacement amplitudes shall be well within the specified allowable limits. The above criterion largely depends on design factors such as size of members, shape of the foundations, concrete grade and soil characters. Presently obtaining a best suitable solution meeting the frequency and amplitude criteria by varying above four design factors involves many manual trails. This involves lot of computer and human efforts to try various combinations to arrive at the solution. Considerable resources and time need to be spent on arriving a suitable solution. Yet the solution so arrived may not be an optimum solution. In this work, Genetic algorithms is applied for optimization of solution time and foundation volume for industrial medium and heavy rotating equipment foundations. Optimum solution is obtained with above variables by setting frequency as target criteria. The optimum solution obtained from Genetic Algorithms is further verified for its compliance to its intended functional parameters by means of finite element model study.","PeriodicalId":7606,"journal":{"name":"American Journal of Civil Engineering","volume":"38 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89624299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.11648/j.ajce.20210906.14
Shen Hong, Yuan Xiuling, Wang Pengyi
: The determination of the most critical non-circular slip surface can be attributed to the optimization of complex non-linear multi-peak function due to its numerous control variables and large amount of calculation. It is a trend in recent years to apply intelligent optimization algorithm into slope stability analysis. Considering that the standard Fruit fly Optimization Algorithm (FOA) is prone to fall into local extremum, the improved Fruit fly Optimization Algorithm is obtained by incorporating the standard FOA with the simulated annealing idea. In order to improve the search efficiency, a fixed step size is adjusted to an adaptive step size, and a double tier search strategy is proposed to be applied: the potential non-circular slip surface is obtained from the outer layer, and the factor of safety along the potential slip surface is calculated step by step from the inner layer. The improved FOA is applied to a slope with weak interlayer. The feasibility, superiority and efficiency of the improved algorithm are proved by comparing its answers to the judges'. Different inter-slice force functions, various initial values of Fs and λ are assumed, and the results show that these parameters could hardly affect final solution for safety factor.
{"title":"Search of Non-circular Slip Surface Based on Improved FOA","authors":"Shen Hong, Yuan Xiuling, Wang Pengyi","doi":"10.11648/j.ajce.20210906.14","DOIUrl":"https://doi.org/10.11648/j.ajce.20210906.14","url":null,"abstract":": The determination of the most critical non-circular slip surface can be attributed to the optimization of complex non-linear multi-peak function due to its numerous control variables and large amount of calculation. It is a trend in recent years to apply intelligent optimization algorithm into slope stability analysis. Considering that the standard Fruit fly Optimization Algorithm (FOA) is prone to fall into local extremum, the improved Fruit fly Optimization Algorithm is obtained by incorporating the standard FOA with the simulated annealing idea. In order to improve the search efficiency, a fixed step size is adjusted to an adaptive step size, and a double tier search strategy is proposed to be applied: the potential non-circular slip surface is obtained from the outer layer, and the factor of safety along the potential slip surface is calculated step by step from the inner layer. The improved FOA is applied to a slope with weak interlayer. The feasibility, superiority and efficiency of the improved algorithm are proved by comparing its answers to the judges'. Different inter-slice force functions, various initial values of Fs and λ are assumed, and the results show that these parameters could hardly affect final solution for safety factor.","PeriodicalId":7606,"journal":{"name":"American Journal of Civil Engineering","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78530712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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