Pub Date : 2020-12-01DOI: 10.22059/CEIJ.2020.271905.1533
M. A. Abyaneh, S. Vahdani, M. Rahimian, M. Mansoori
A new macroscopic four node reinforced concrete shear wall element is presented. The element is capable of considering the effect of wall opening without any divisions in the element. Accordingly, the opening may be located arbitrary inside the element. Furthermore, three degrees of freedom are suggested here at each node, totally compatible with the surrounding frame elements. The element is considered only for in-plane stiffness of the wall. Therefore, the surrounding frame elements are assumed to be assembled separately which provides a suitable modeling condition. The element consists of vertical springs, horizontal springs and a shear membrane shell. No rigid element is used in the assembly for imposing the bending action; however, the compatibility is achieved using the definition of shape functions. The element is developed and evaluated in linear applications. The results indicate that some major defects of other macroscopic shear wall elements are removed by the proposed element.
{"title":"Implementation of a New Macroscopic Shear Wall Element","authors":"M. A. Abyaneh, S. Vahdani, M. Rahimian, M. Mansoori","doi":"10.22059/CEIJ.2020.271905.1533","DOIUrl":"https://doi.org/10.22059/CEIJ.2020.271905.1533","url":null,"abstract":"A new macroscopic four node reinforced concrete shear wall element is presented. The element is capable of considering the effect of wall opening without any divisions in the element. Accordingly, the opening may be located arbitrary inside the element. Furthermore, three degrees of freedom are suggested here at each node, totally compatible with the surrounding frame elements. The element is considered only for in-plane stiffness of the wall. Therefore, the surrounding frame elements are assumed to be assembled separately which provides a suitable modeling condition. The element consists of vertical springs, horizontal springs and a shear membrane shell. No rigid element is used in the assembly for imposing the bending action; however, the compatibility is achieved using the definition of shape functions. The element is developed and evaluated in linear applications. The results indicate that some major defects of other macroscopic shear wall elements are removed by the proposed element.","PeriodicalId":43959,"journal":{"name":"Civil Engineering Infrastructures Journal-CEIJ","volume":"53 1","pages":"207-226"},"PeriodicalIF":1.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45173431","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 : 2020-12-01DOI: 10.22059/CEIJ.2020.287376.1606
Hossein Honarvar, M. Shayanfar, Behrouz Babakhani, M. Zabihi‑Samani
This paper investigates the composite beam with bolt shear connectors. Composite beams are usually used as secondary beam in buildings. It is clear that studying the torsion in side beams in buildings such as balconies is of great importance. The composite beam was loaded under three different loading conditions including a pure flexural loading, and simultaneous flexural loading with two alternative torsional loading modes. The obtained results from the analysis were compared with each other by three-dimensional non-linear finite element model using ABAQUS. The obtained results, including the mid span deflection, the rotation and slip of composite beams under different loading conditions were investigated. The effect of the type and number of shear connectors on slip of composite beam was studied, too. The results indicated that the slip between the steel beam and the concrete slab along the composite beam increased due to flexure loading, but the torsional loading had a slight effect on the slip.
{"title":"Numerical Analysis of Steel-Concrete Composite Beam with Blind Bolt under Simultaneous Flexural and Torsional Loading","authors":"Hossein Honarvar, M. Shayanfar, Behrouz Babakhani, M. Zabihi‑Samani","doi":"10.22059/CEIJ.2020.287376.1606","DOIUrl":"https://doi.org/10.22059/CEIJ.2020.287376.1606","url":null,"abstract":"This paper investigates the composite beam with bolt shear connectors. Composite beams are usually used as secondary beam in buildings. It is clear that studying the torsion in side beams in buildings such as balconies is of great importance. The composite beam was loaded under three different loading conditions including a pure flexural loading, and simultaneous flexural loading with two alternative torsional loading modes. The obtained results from the analysis were compared with each other by three-dimensional non-linear finite element model using ABAQUS. The obtained results, including the mid span deflection, the rotation and slip of composite beams under different loading conditions were investigated. The effect of the type and number of shear connectors on slip of composite beam was studied, too. The results indicated that the slip between the steel beam and the concrete slab along the composite beam increased due to flexure loading, but the torsional loading had a slight effect on the slip.","PeriodicalId":43959,"journal":{"name":"Civil Engineering Infrastructures Journal-CEIJ","volume":"53 1","pages":"379-393"},"PeriodicalIF":1.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45709429","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 : 2020-12-01DOI: 10.22059/CEIJ.2019.283574.1591
M. Moradi, H. Tavakoli
One of the aims of earthquake engineering is to build secure structures against random loads and also various damage types under lateral loads. Progressive collapse, a word that has attracted attention of many researches after the failure of the World Trade Center, can occur under abnormal loads such as explosion or natural causes like earthquakes. Resistance to progressive collapse is expressed by a parameter called Robustness. The purpose of this study is to survey various methods of calculating robustness index under lateral loads, especially seismic loads, in steel moment frames. So three steel structures with 4, 8 and 15-story and intermediate moment frames were designed and analyzed subsequently. Different methods of measuring the robustness indexes were compared and eventually presented a simple method to assess robustness index based on nonlinear dynamic analysis. Robustness index introduced using this method, which is based on the types of Pancake and Zipper collapses and energy parameters, tries to express an appropriate standard for structural strength against earthquakes.
{"title":"Proposal of an Energy Based Assessment of Robustness Index of Steel Moment Frames under the Seismic Progressive Collapse","authors":"M. Moradi, H. Tavakoli","doi":"10.22059/CEIJ.2019.283574.1591","DOIUrl":"https://doi.org/10.22059/CEIJ.2019.283574.1591","url":null,"abstract":"One of the aims of earthquake engineering is to build secure structures against random loads and also various damage types under lateral loads. Progressive collapse, a word that has attracted attention of many researches after the failure of the World Trade Center, can occur under abnormal loads such as explosion or natural causes like earthquakes. Resistance to progressive collapse is expressed by a parameter called Robustness. The purpose of this study is to survey various methods of calculating robustness index under lateral loads, especially seismic loads, in steel moment frames. So three steel structures with 4, 8 and 15-story and intermediate moment frames were designed and analyzed subsequently. Different methods of measuring the robustness indexes were compared and eventually presented a simple method to assess robustness index based on nonlinear dynamic analysis. Robustness index introduced using this method, which is based on the types of Pancake and Zipper collapses and energy parameters, tries to express an appropriate standard for structural strength against earthquakes.","PeriodicalId":43959,"journal":{"name":"Civil Engineering Infrastructures Journal-CEIJ","volume":"53 1","pages":"277-293"},"PeriodicalIF":1.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43981840","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 : 2020-12-01DOI: 10.22059/CEIJ.2020.283400.1590
Sina Sarfarazi, H. Saffari, A. Fakhraddini
Panel zone is a part of a column web where surrounded by the continuity plates and the column flanges. Panel zone plays a vital role in the connection behavior. Despite the upward tendency of using cruciform section in many seismic regions, few studies have focused on the behavior of these columns, and especially on the behavior of their panel zone. As well, some recent studies have shown that axial load has a remarkable effect on the yielding process of the panel zone. In this research, a mathematical model is presented to consider the effect of axial force on the behavior of the panel zone in the cruciform columns. The model included the shear stiffness of the panel zone in the elastic and non-elastic region, the yield shear and the ultimate shear capacity of the panel zone. Consequently, 432 Finite Element Models (FEM) in a wide range of dimensions are performed and a parametric study has been done. The comparisons of the results of proposed mathematical model with the results of all Finite Element models demonstrate that the average and maximum deviation for yield and ultimate shear strength of the panel zone are respectively 5.32%, 8.12%, 6.2%, and 8.44%. This matter exhibits the accuracy and efficiency of the proposed mathematical relations.
{"title":"Shear Behavior of Panel Zone Considering Axial Force for Flanged Cruciform Columns","authors":"Sina Sarfarazi, H. Saffari, A. Fakhraddini","doi":"10.22059/CEIJ.2020.283400.1590","DOIUrl":"https://doi.org/10.22059/CEIJ.2020.283400.1590","url":null,"abstract":"Panel zone is a part of a column web where surrounded by the continuity plates and the column flanges. Panel zone plays a vital role in the connection behavior. Despite the upward tendency of using cruciform section in many seismic regions, few studies have focused on the behavior of these columns, and especially on the behavior of their panel zone. As well, some recent studies have shown that axial load has a remarkable effect on the yielding process of the panel zone. In this research, a mathematical model is presented to consider the effect of axial force on the behavior of the panel zone in the cruciform columns. The model included the shear stiffness of the panel zone in the elastic and non-elastic region, the yield shear and the ultimate shear capacity of the panel zone. Consequently, 432 Finite Element Models (FEM) in a wide range of dimensions are performed and a parametric study has been done. The comparisons of the results of proposed mathematical model with the results of all Finite Element models demonstrate that the average and maximum deviation for yield and ultimate shear strength of the panel zone are respectively 5.32%, 8.12%, 6.2%, and 8.44%. This matter exhibits the accuracy and efficiency of the proposed mathematical relations.","PeriodicalId":43959,"journal":{"name":"Civil Engineering Infrastructures Journal-CEIJ","volume":"53 1","pages":"359-377"},"PeriodicalIF":1.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46298544","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 : 2020-12-01DOI: 10.22059/CEIJ.2019.284169.1594
Sajjad Salehi, M. Davoodi, S. Mostafavian
In large civil engineering structures, the output-only modal identification is the most applicable technique for estimating the modal parameters such as damping. However, due to no measurement and control of excitation force, the identified parameters obtained by output-only technique have more uncertainty than those derived from the input-output technique. Given the different nature and uncertainties of the two modal identification techniques, in the present study, the damping related to the first 12 modes of a double-layer grid developed from the ball joint system were identified via the two techniques and compared with each other. For this purpose, a double-layer grid was constructed by pipes and balls with free-free boundary conditions provided for both input-output and output-only experiments. Exciting the grid, its acceleration response was measured at appropriate degrees of freedom. Then, by using these data and performing modal analysis, involving four different methods of input-output and five different methods of output-only, the natural frequencies and damping ratios of the desired modes were extracted. The results indicated that despite the good agreement between the modal damping of the grid, as identified by different methods of input-output together and by different methods of output-only together, the results of input-output and output-only methods were different with each other. The damping values through the input-output modal identification methods were on average 65% higher than the corresponding values of the output-only modal identification methods.
{"title":"Estimation of Damping for a Double-Layer Grid Using Input-Output and Output-Only Modal Identification Techniques","authors":"Sajjad Salehi, M. Davoodi, S. Mostafavian","doi":"10.22059/CEIJ.2019.284169.1594","DOIUrl":"https://doi.org/10.22059/CEIJ.2019.284169.1594","url":null,"abstract":"In large civil engineering structures, the output-only modal identification is the most applicable technique for estimating the modal parameters such as damping. However, due to no measurement and control of excitation force, the identified parameters obtained by output-only technique have more uncertainty than those derived from the input-output technique. Given the different nature and uncertainties of the two modal identification techniques, in the present study, the damping related to the first 12 modes of a double-layer grid developed from the ball joint system were identified via the two techniques and compared with each other. For this purpose, a double-layer grid was constructed by pipes and balls with free-free boundary conditions provided for both input-output and output-only experiments. Exciting the grid, its acceleration response was measured at appropriate degrees of freedom. Then, by using these data and performing modal analysis, involving four different methods of input-output and five different methods of output-only, the natural frequencies and damping ratios of the desired modes were extracted. The results indicated that despite the good agreement between the modal damping of the grid, as identified by different methods of input-output together and by different methods of output-only together, the results of input-output and output-only methods were different with each other. The damping values through the input-output modal identification methods were on average 65% higher than the corresponding values of the output-only modal identification methods.","PeriodicalId":43959,"journal":{"name":"Civil Engineering Infrastructures Journal-CEIJ","volume":"53 1","pages":"295-311"},"PeriodicalIF":1.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42189557","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 : 2020-06-01DOI: 10.22059/CEIJ.2020.282153.1587
A. Ghassemi, Seyed Sahand Shahebrahimi
Dynamic Compaction (DC) is a common deep compaction method that is usually used for densification of coarse-grained soils. Although traditional continuum-based models such as the Finite Element Method can be successfully applied for assessment of stress distributions or deformations induced by DC, they are typically not adequate for capturing the grain scale mechanisms of soil behavior under impact. In contrast, numerical models such as Discrete Element Method (DEM) in which the interaction of constituting distinct elements is explicitly simulated are promising for simulation of DC process. In this study, dynamic compaction in a dry rockfill was simulated through a two-dimensional DEM model. Based on the developed model, a series of analyses with various tamper weights and drop heights were conducted to investigate the effects of important factors such as energy and momentum per drop on DC results. Comparison of the obtained results with experimental observations reveal the capability of DEM for simulation of DC. The numerical simulations also confirm the positive effect of using conical-based tampers in DC process.
{"title":"Discrete Element Modeling of Dynamic Compaction with Different Tamping Condition","authors":"A. Ghassemi, Seyed Sahand Shahebrahimi","doi":"10.22059/CEIJ.2020.282153.1587","DOIUrl":"https://doi.org/10.22059/CEIJ.2020.282153.1587","url":null,"abstract":"Dynamic Compaction (DC) is a common deep compaction method that is usually used for densification of coarse-grained soils. Although traditional continuum-based models such as the Finite Element Method can be successfully applied for assessment of stress distributions or deformations induced by DC, they are typically not adequate for capturing the grain scale mechanisms of soil behavior under impact. In contrast, numerical models such as Discrete Element Method (DEM) in which the interaction of constituting distinct elements is explicitly simulated are promising for simulation of DC process. In this study, dynamic compaction in a dry rockfill was simulated through a two-dimensional DEM model. Based on the developed model, a series of analyses with various tamper weights and drop heights were conducted to investigate the effects of important factors such as energy and momentum per drop on DC results. Comparison of the obtained results with experimental observations reveal the capability of DEM for simulation of DC. The numerical simulations also confirm the positive effect of using conical-based tampers in DC process.","PeriodicalId":43959,"journal":{"name":"Civil Engineering Infrastructures Journal-CEIJ","volume":"53 1","pages":"173-188"},"PeriodicalIF":1.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44204564","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 : 2020-06-01DOI: 10.22059/CEIJ.2019.279837.1578
A. Ghanizadeh, N. Heidarabadizadeh, M. Mahmoodabadi
The main purpose of this work is the comparison of several objective functions for optimization of the vertical alignment. To this end, after formulation of optimum vertical alignment problem based on different constraints, the objective function was considered as four forms including: 1) the sum of the absolute value of variance between the vertical alignment and the existing ground; 2) the sum of the absolute value of variance between the vertical alignment and the existing ground based on the diverse weights for cuts and fills; 3) the sum of cut and fill volumes; and 4) the earthwork cost and then the value of objective function was compared for the first three cases with the last one, which was the most accurate ones. In order to optimize the raised problem, Genetic Algorithm (GA) and Group Search Optimization (GSO) were implemented and performance of these two optimization algorithms were also compared. This research proves that the minimization of sum of the absolute value of variance between the vertical alignment and the existing ground, which is commonly used for design of vertical alignment, can’t at all grantee the optimum vertical alignment in terms of earthwork cost.
{"title":"Effect of Objective Function on the Optimization of Highway Vertical Alignment by Means of Metaheuristic Algorithms","authors":"A. Ghanizadeh, N. Heidarabadizadeh, M. Mahmoodabadi","doi":"10.22059/CEIJ.2019.279837.1578","DOIUrl":"https://doi.org/10.22059/CEIJ.2019.279837.1578","url":null,"abstract":"The main purpose of this work is the comparison of several objective functions for optimization of the vertical alignment. To this end, after formulation of optimum vertical alignment problem based on different constraints, the objective function was considered as four forms including: 1) the sum of the absolute value of variance between the vertical alignment and the existing ground; 2) the sum of the absolute value of variance between the vertical alignment and the existing ground based on the diverse weights for cuts and fills; 3) the sum of cut and fill volumes; and 4) the earthwork cost and then the value of objective function was compared for the first three cases with the last one, which was the most accurate ones. In order to optimize the raised problem, Genetic Algorithm (GA) and Group Search Optimization (GSO) were implemented and performance of these two optimization algorithms were also compared. This research proves that the minimization of sum of the absolute value of variance between the vertical alignment and the existing ground, which is commonly used for design of vertical alignment, can’t at all grantee the optimum vertical alignment in terms of earthwork cost.","PeriodicalId":43959,"journal":{"name":"Civil Engineering Infrastructures Journal-CEIJ","volume":"53 1","pages":"115-136"},"PeriodicalIF":1.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44495272","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 : 2020-06-01DOI: 10.22059/CEIJ.2020.271142.1531
Seyed Ahmad Mobinipour, S. Pourzeynali
Nowadays it is common to use the fragility curves in probabilistic methods to determine the collapse probability resulting from an earthquake. The uncertainties exist in intensity and frequency content of the earthquake records are considered as the most effective parameters in developing the fragility curves. The pulse-type records reported in the near-fault regions might lead to the major damages in the structures having moderate and long periods since response spectra of near-fault ground motions within the long period range are different from those of the far-fault ground motions. In the present study, the influence of this type of earthquake records on the fragility curves of the steel special moment resisting frames, SMRFs, was examined. The results indicated that the median value of the collapse capacity (i.e.ŜCt Parameter, which defines the earthquake intensity leading to the collapse of the structure in half-set of the chosen records) due to near-fault ground motions was 76% that of the far-fault records for the ten-story example SMRF.
{"title":"Assessment of Near-Fault Ground Motion Effects on the Fragility Curves of Tall Steel Moment Resisting Frames","authors":"Seyed Ahmad Mobinipour, S. Pourzeynali","doi":"10.22059/CEIJ.2020.271142.1531","DOIUrl":"https://doi.org/10.22059/CEIJ.2020.271142.1531","url":null,"abstract":"Nowadays it is common to use the fragility curves in probabilistic methods to determine the collapse probability resulting from an earthquake. The uncertainties exist in intensity and frequency content of the earthquake records are considered as the most effective parameters in developing the fragility curves. The pulse-type records reported in the near-fault regions might lead to the major damages in the structures having moderate and long periods since response spectra of near-fault ground motions within the long period range are different from those of the far-fault ground motions. In the present study, the influence of this type of earthquake records on the fragility curves of the steel special moment resisting frames, SMRFs, was examined. The results indicated that the median value of the collapse capacity (i.e.ŜCt Parameter, which defines the earthquake intensity leading to the collapse of the structure in half-set of the chosen records) due to near-fault ground motions was 76% that of the far-fault records for the ten-story example SMRF.","PeriodicalId":43959,"journal":{"name":"Civil Engineering Infrastructures Journal-CEIJ","volume":"53 1","pages":"71-88"},"PeriodicalIF":1.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46961272","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 : 2020-06-01DOI: 10.22059/CEIJ.2020.281914.1586
Amin Motallebiyan, M. Bayat, B. Nadi
The use of wind turbines to generate electricity has increased in recent years. One of the most important parts of a wind turbine is the foundation, which should be designed accurately because it is influenced by difference forces. Soil cannot carry tension stress; thus, when a wind turbine foundation is applied eccentricity forces, a gap appears between the soil and foundation. The gap will have no positive effect on the ultimate bearing capacity of the foundation. This must be considered when designing the dimensions of an onshore wind turbine on a spread foundation using finite element software in order to avoid error during analysis. In the current study, a spread foundation of an onshore wind turbine was simulated using ABAQUS and PLAXIS-3D software. Based on the results, the effects of Soil-Structure Interaction (SSI), eccentricity of forces, soil strength parameters and the foundation buried depth on static response of the foundation are discussed. The results indicate that the influence of soil-structure interaction is depend on magnitude of eccentricity of forces and depth of foundation, so that soil-structure interaction has little impact on settlement of foundation when eccentricity of forces is less than 1/6 of the diameter of the foundation and this has important effect when the eccentricity forces at an amount exceeding 1/6 of the diameter of the foundation. In addition, this effect decreases with increasing the foundation buried depth and independent of the soil strength parameters (φ´ and C).
{"title":"Analyzing the Effects of Soil-Structure Interactions on the Static Response of Onshore Wind Turbine Foundations Using Finite Element Method","authors":"Amin Motallebiyan, M. Bayat, B. Nadi","doi":"10.22059/CEIJ.2020.281914.1586","DOIUrl":"https://doi.org/10.22059/CEIJ.2020.281914.1586","url":null,"abstract":"The use of wind turbines to generate electricity has increased in recent years. One of the most important parts of a wind turbine is the foundation, which should be designed accurately because it is influenced by difference forces. Soil cannot carry tension stress; thus, when a wind turbine foundation is applied eccentricity forces, a gap appears between the soil and foundation. The gap will have no positive effect on the ultimate bearing capacity of the foundation. This must be considered when designing the dimensions of an onshore wind turbine on a spread foundation using finite element software in order to avoid error during analysis. In the current study, a spread foundation of an onshore wind turbine was simulated using ABAQUS and PLAXIS-3D software. Based on the results, the effects of Soil-Structure Interaction (SSI), eccentricity of forces, soil strength parameters and the foundation buried depth on static response of the foundation are discussed. The results indicate that the influence of soil-structure interaction is depend on magnitude of eccentricity of forces and depth of foundation, so that soil-structure interaction has little impact on settlement of foundation when eccentricity of forces is less than 1/6 of the diameter of the foundation and this has important effect when the eccentricity forces at an amount exceeding 1/6 of the diameter of the foundation. In addition, this effect decreases with increasing the foundation buried depth and independent of the soil strength parameters (φ´ and C).","PeriodicalId":43959,"journal":{"name":"Civil Engineering Infrastructures Journal-CEIJ","volume":"53 1","pages":"189-205"},"PeriodicalIF":1.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42233179","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 : 2020-06-01DOI: 10.22059/CEIJ.2019.276295.1555
A. Kavussi, Behzad Naderi
Cohesion properties of the binder matrix within asphalt mixes and adhesion characteristics of the asphalt binder and aggregate particles are the two major mechanisms resisting against cracking in asphalt mixes. This study is focused on estimating crack resistance of asphalt mixes at intermediate temperatures through evaluation of cohesion and adhesion properties of binder-aggregate systems using Surface Free Energy (SFE) method. Semi-Circular Bending test (SCB) was used to support the SFE analysis. SFE measurements were performed applying Sessile Drop test method. A Granite aggregate type and two asphalt binders (PG64-16, PG58-22) containing various amounts of SBS polymer were used to produce six groups of asphalt mixes. Cohesion and adhesion energies obtained from SFE analysis and Flexibility Indexes and Fracture Energies determined in SCB test showed the positive effect of SBS on performance of asphalt mixes at intermediate temperatures, although the effectiveness of SBS modification was more pronounced with SCB parameters. A linear regression was performed and a strong correlation was observed between SFE results and SCB parameters.
{"title":"Application of SCB Test and Surface Free Energy Method in Evaluating Crack Resistance of SBS Modified Asphalt Mixes","authors":"A. Kavussi, Behzad Naderi","doi":"10.22059/CEIJ.2019.276295.1555","DOIUrl":"https://doi.org/10.22059/CEIJ.2019.276295.1555","url":null,"abstract":"Cohesion properties of the binder matrix within asphalt mixes and adhesion characteristics of the asphalt binder and aggregate particles are the two major mechanisms resisting against cracking in asphalt mixes. This study is focused on estimating crack resistance of asphalt mixes at intermediate temperatures through evaluation of cohesion and adhesion properties of binder-aggregate systems using Surface Free Energy (SFE) method. Semi-Circular Bending test (SCB) was used to support the SFE analysis. SFE measurements were performed applying Sessile Drop test method. A Granite aggregate type and two asphalt binders (PG64-16, PG58-22) containing various amounts of SBS polymer were used to produce six groups of asphalt mixes. Cohesion and adhesion energies obtained from SFE analysis and Flexibility Indexes and Fracture Energies determined in SCB test showed the positive effect of SBS on performance of asphalt mixes at intermediate temperatures, although the effectiveness of SBS modification was more pronounced with SCB parameters. A linear regression was performed and a strong correlation was observed between SFE results and SCB parameters.","PeriodicalId":43959,"journal":{"name":"Civil Engineering Infrastructures Journal-CEIJ","volume":"53 1","pages":"103-114"},"PeriodicalIF":1.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46921184","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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