Mohamed Youssef Abd El-Latif, Ayman Lotfy Fayed, Mahmoud E. Hassan
Effective use of natural materials and industrial by products has a direct impact on economy, sustainable environment, and waste management. Poorly graded desert sand (SP) is widely observed in sand dunes and sand seas. Studies were performed to get beneficial use of cement kiln dust (CKD) in soil improvement. But there is a lack of information concerning using of CKD as an improving material for poorly graded sand with the aid of salt water. Salt water is widely available in Egypt from seas and some deep wells, using it will help in saving drink water which suffers from shortage in many countries. The aim of this research is to study the possibility of improving SP using CKD and salt water to be used in backfilling work and subbase layers of roads and pavements. Mixtures of poorly graded sand and various CKD ratios (10%, 20% and 30%) were classified and tested using grain size distribution, compaction, shear strength and California bearing tests. The results were compared with potable water. The results show that adding CKD improves the characteristic properties of SP even with salt water. The study enhances the using of 20% CKD with optimum water content of 9.12% of salt water to have noticeable improvement for SP and to be used efficiently in backfilling and subbase layers.
{"title":"Sustainable Stabilization of Poorly Graded Desert Sand by Cement Kiln Dust and Salt Water for Using in Backfilling and Subbase Layers","authors":"Mohamed Youssef Abd El-Latif, Ayman Lotfy Fayed, Mahmoud E. Hassan","doi":"10.3311/ppci.21915","DOIUrl":"https://doi.org/10.3311/ppci.21915","url":null,"abstract":"Effective use of natural materials and industrial by products has a direct impact on economy, sustainable environment, and waste management. Poorly graded desert sand (SP) is widely observed in sand dunes and sand seas. Studies were performed to get beneficial use of cement kiln dust (CKD) in soil improvement. But there is a lack of information concerning using of CKD as an improving material for poorly graded sand with the aid of salt water. Salt water is widely available in Egypt from seas and some deep wells, using it will help in saving drink water which suffers from shortage in many countries. The aim of this research is to study the possibility of improving SP using CKD and salt water to be used in backfilling work and subbase layers of roads and pavements. Mixtures of poorly graded sand and various CKD ratios (10%, 20% and 30%) were classified and tested using grain size distribution, compaction, shear strength and California bearing tests. The results were compared with potable water. The results show that adding CKD improves the characteristic properties of SP even with salt water. The study enhances the using of 20% CKD with optimum water content of 9.12% of salt water to have noticeable improvement for SP and to be used efficiently in backfilling and subbase layers.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86938328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abderrahmane Abdesselam, A. Merdas, B. Fiorio, N. Chikh
Near Surface Mounted (NSM) Carbon Fiber-Reinforced Polymer (CFRP) reinforcement technique to improve the flexural strength of reinforced concrete members has become increasingly attractive in recent years. In this study, the practical problem of concrete cover depth cutting limitation was investigated. Twelve specimens were tested by four-point bending until failure. Experimental parameters include concrete cover depth, CFRP reinforcement type, CFRP positioning, and stirrups status. Furthermore, a nonlinear FEA model was developed to simulate the tested beams and was able to predict the experimental behavior satisfactorily. A series of parametric studies were then performed using this model to understand the effect of various reinforcement parameters on the flexural performance of the beam. The results showed that Strengthening with CFRP resulted in a significant increase in yield and ultimate strengths, but a significant ductility loss was recorded due to CFRP strip debonding in the strengthened beams, this problem was addressed by using more efficient strengthening techniques utilizing the effective bond length and a proper groove depth and positioning for the NSM bars.
{"title":"Experimental and Numerical Study on RC Beams Strengthened by NSM Using CFRP Reinforcements","authors":"Abderrahmane Abdesselam, A. Merdas, B. Fiorio, N. Chikh","doi":"10.3311/ppci.21309","DOIUrl":"https://doi.org/10.3311/ppci.21309","url":null,"abstract":"Near Surface Mounted (NSM) Carbon Fiber-Reinforced Polymer (CFRP) reinforcement technique to improve the flexural strength of reinforced concrete members has become increasingly attractive in recent years. In this study, the practical problem of concrete cover depth cutting limitation was investigated. Twelve specimens were tested by four-point bending until failure. Experimental parameters include concrete cover depth, CFRP reinforcement type, CFRP positioning, and stirrups status. Furthermore, a nonlinear FEA model was developed to simulate the tested beams and was able to predict the experimental behavior satisfactorily. A series of parametric studies were then performed using this model to understand the effect of various reinforcement parameters on the flexural performance of the beam. The results showed that Strengthening with CFRP resulted in a significant increase in yield and ultimate strengths, but a significant ductility loss was recorded due to CFRP strip debonding in the strengthened beams, this problem was addressed by using more efficient strengthening techniques utilizing the effective bond length and a proper groove depth and positioning for the NSM bars.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80859858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, two groups of foam glass aggregate (FGA) samples were prepared with four different compaction ratios (10%, 20%, 30%, and 40%) and subjected to a series of static compressional loads from 50kPa to 300kPa with 50kPa interval. In first group of the test (changed load samples, ChLS), for each static load value, a new sample was prepared and tested. In the other group of the test (continuously loaded samples, CLS), all prescribed static compressional loads were sequentially applied over the same sample after satisfying the required strain rate at each load. The results revealed that the overall vertical strain values of CLS were lower than ChLS except for 10%, which shows reverse behavior. For both sample types, the required time to reach the desired vertical strain rate was much higher when the compaction ratio was low, and the compressional load was above 250 kPa. The compaction methodology used in the present study led to more reliable vertical strain values for both short- and long-term loading periods compared to other reported results executed on FGA under the same static compressional load circumstances. The evolution in the particle distribution curve of FGA particles after maximum compaction ratio (40%) was nonsignificant compared to the study works that depended on traditional standard test methods of compaction and led to severe change in particles structural component. The current findings beneficially affect civil engineering applications using FGA by defining the material's final strain values when subjected to static compressional loads at different compaction ratios.
{"title":"Effect of Static Loading States on the Compressional Behavior of Foam Glass Aggregate","authors":"W. Mustafa, J. Szendefy","doi":"10.3311/ppci.21973","DOIUrl":"https://doi.org/10.3311/ppci.21973","url":null,"abstract":"In this study, two groups of foam glass aggregate (FGA) samples were prepared with four different compaction ratios (10%, 20%, 30%, and 40%) and subjected to a series of static compressional loads from 50kPa to 300kPa with 50kPa interval. In first group of the test (changed load samples, ChLS), for each static load value, a new sample was prepared and tested. In the other group of the test (continuously loaded samples, CLS), all prescribed static compressional loads were sequentially applied over the same sample after satisfying the required strain rate at each load. The results revealed that the overall vertical strain values of CLS were lower than ChLS except for 10%, which shows reverse behavior. For both sample types, the required time to reach the desired vertical strain rate was much higher when the compaction ratio was low, and the compressional load was above 250 kPa. The compaction methodology used in the present study led to more reliable vertical strain values for both short- and long-term loading periods compared to other reported results executed on FGA under the same static compressional load circumstances. The evolution in the particle distribution curve of FGA particles after maximum compaction ratio (40%) was nonsignificant compared to the study works that depended on traditional standard test methods of compaction and led to severe change in particles structural component. The current findings beneficially affect civil engineering applications using FGA by defining the material's final strain values when subjected to static compressional loads at different compaction ratios.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89418303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Remote sensing technologies such as laser scanning and photogrammetry have advanced significantly in the field-to-BIM workflow in recent years, becoming key instruments for modeling as-built frameworks. They can be utilized to collect dense 3D measured data on the condition of a building, and the derived point cloud can be processed to generate the as-built BIM. It provides building information to report as-built conditions and serves as a skill set for data on problem-solving issues in civil engineering. This research presents an efficient and automated workflow for modifying and evaluating point cloud data, focusing on supporting scan-to-BIM operations. The workflow utilizes cubic voxel mesh creation and voxel subsampling techniques to ensure precise representation of scanned data. The validation of this reconstruction methodology using Grasshopper and Volvox demonstrates its potential to reduce manual labor and analysis typically required in conventional scan-to-BIM methodologies. The presented workflow simplifies the critical task of acquiring building profiles, an essential BIM result, and streamlines the overall process. The integration of the Volvox plugin has further augmented the capabilities of Grasshopper and Rhino, providing users with intuitive tools for manipulating point clouds. Automating certain operations through the presented workflow has significant potential to enhance the efficiency and accuracy of the scan-to-BIM methodologies. These findings have implications in architecture and design, demonstrating how technology can be leveraged to unlock new possibilities and streamline critical processes.
{"title":"Automating Scan to BIM Operations Using Grasshopper","authors":"Ifra Aftab, K. Kapitany, T. Lovas","doi":"10.3311/ppci.22390","DOIUrl":"https://doi.org/10.3311/ppci.22390","url":null,"abstract":"Remote sensing technologies such as laser scanning and photogrammetry have advanced significantly in the field-to-BIM workflow in recent years, becoming key instruments for modeling as-built frameworks. They can be utilized to collect dense 3D measured data on the condition of a building, and the derived point cloud can be processed to generate the as-built BIM. It provides building information to report as-built conditions and serves as a skill set for data on problem-solving issues in civil engineering. This research presents an efficient and automated workflow for modifying and evaluating point cloud data, focusing on supporting scan-to-BIM operations. The workflow utilizes cubic voxel mesh creation and voxel subsampling techniques to ensure precise representation of scanned data. The validation of this reconstruction methodology using Grasshopper and Volvox demonstrates its potential to reduce manual labor and analysis typically required in conventional scan-to-BIM methodologies. The presented workflow simplifies the critical task of acquiring building profiles, an essential BIM result, and streamlines the overall process. The integration of the Volvox plugin has further augmented the capabilities of Grasshopper and Rhino, providing users with intuitive tools for manipulating point clouds. Automating certain operations through the presented workflow has significant potential to enhance the efficiency and accuracy of the scan-to-BIM methodologies. These findings have implications in architecture and design, demonstrating how technology can be leveraged to unlock new possibilities and streamline critical processes.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84424755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The interaction behavior between local and global buckling modes in high-strength steel box-section columns has received limited research attention. Currently, there is a lack of a validated equivalent geometric imperfection that can be effectively employed in nonlinear plastic analysis to estimate the interaction buckling resistance. This research aims to find equivalent geometric imperfections that can be used in geometrical and materially nonlinear analysis using imperfections (GMNIA) to estimate the interaction buckling resistance of square welded box-section columns made of high-strength steel. It extends prior investigations by the authors on equivalent imperfections for normal-strength steel welded box-sections. A developed and validated numerical model is used to perform parametric studies to estimate the accurate buckling capacity using previously developed and verified combinations of imperfections and residual stresses. The accurate buckling capacities are used to calibrate equivalent local and global imperfection combinations that can be used in FEM-based design. A reliability assessment study is also performed to check the safety level of the proposed imperfection combinations.
{"title":"Imperfections for Local and Global Interaction Buckling of Welded Square High-strength Steel Box-section Columns","authors":"M. Radwan, B. Kövesdi","doi":"10.3311/ppci.22226","DOIUrl":"https://doi.org/10.3311/ppci.22226","url":null,"abstract":"The interaction behavior between local and global buckling modes in high-strength steel box-section columns has received limited research attention. Currently, there is a lack of a validated equivalent geometric imperfection that can be effectively employed in nonlinear plastic analysis to estimate the interaction buckling resistance. This research aims to find equivalent geometric imperfections that can be used in geometrical and materially nonlinear analysis using imperfections (GMNIA) to estimate the interaction buckling resistance of square welded box-section columns made of high-strength steel. It extends prior investigations by the authors on equivalent imperfections for normal-strength steel welded box-sections. A developed and validated numerical model is used to perform parametric studies to estimate the accurate buckling capacity using previously developed and verified combinations of imperfections and residual stresses. The accurate buckling capacities are used to calibrate equivalent local and global imperfection combinations that can be used in FEM-based design. A reliability assessment study is also performed to check the safety level of the proposed imperfection combinations.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86539945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In recent years, artificial neural network (ANN) has become one of the popular and effective machine learning models, having a unique ability to handle very complex problems and the potential to predict accurate results without a defined algorithmic solution. However, the ANN structure and parameters are usually chosen by experience.The behavior of Partially Grouted (PG) masonry shear walls is complex due to the inherent anisotropic properties of the masonry materials and the nonlinear interactions between mortar, blocks, grouted cells, non-grouted cells, and reinforcing steel.In this study, the aim is to develop an artificial neural network model by combining the ECBO meta-heuristic algorithm with the artificial neural network structure to optimize the feed forward propagation network parameters for analyzing the shear strength of PG walls.A total of 255 test data on PG collected from the available literature were used to generate training and test data sets. Various validation criteria such as mean square error, root mean square error and correlation coefficient (R) are used to validate the models.In this study, the optimal number of neurons used in the hidden layer and also the optimal number of CBs required in the ECBO algorithm were obtained. The mathematical formulation of the optimized neural network model with the combination of meta-heuristic algorithm is also presented.
{"title":"Hybrid ECBO–ANN Algorithm for Shear Strength of Partially Grouted Masonry Walls","authors":"A. Kaveh, Neda Khavaninzadeh","doi":"10.3311/ppci.22653","DOIUrl":"https://doi.org/10.3311/ppci.22653","url":null,"abstract":"In recent years, artificial neural network (ANN) has become one of the popular and effective machine learning models, having a unique ability to handle very complex problems and the potential to predict accurate results without a defined algorithmic solution. However, the ANN structure and parameters are usually chosen by experience.The behavior of Partially Grouted (PG) masonry shear walls is complex due to the inherent anisotropic properties of the masonry materials and the nonlinear interactions between mortar, blocks, grouted cells, non-grouted cells, and reinforcing steel.In this study, the aim is to develop an artificial neural network model by combining the ECBO meta-heuristic algorithm with the artificial neural network structure to optimize the feed forward propagation network parameters for analyzing the shear strength of PG walls.A total of 255 test data on PG collected from the available literature were used to generate training and test data sets. Various validation criteria such as mean square error, root mean square error and correlation coefficient (R) are used to validate the models.In this study, the optimal number of neurons used in the hidden layer and also the optimal number of CBs required in the ECBO algorithm were obtained. The mathematical formulation of the optimized neural network model with the combination of meta-heuristic algorithm is also presented.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79119523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper aims to assess the behavior of the unconfined compressive strength (UCS) of polypropylene fiber (PF) reinforced natural pozzolana-lime-stabilized expansive grey clayey soil (GS) contaminated by sulfates. Lime (0–8%), natural pozzolana (NP) (0–20%), and PF (0–3%) by dry weight of soil were used. GS was contaminated by different sulfate contents (0-6%) and UCS was assessed at various curing periods (7–120 days). Results showed that adding 8% lime alone or with 20% NP considerably improved UCS. Including 1% or 2% PF as reinforcement without sulfates in lime-stabilized GS transferred stress from GS to PF due to bonding. However, increasing PF beyond 2% formed lumps, reducing contact and friction coefficient, thus decreasing UCS. This means that the optimum PF dosage was found to be 2%. The UCS of GS increased with PF content up to 2% and then decreased. The UCS significantly increased with higher calcium sulfate content and curing period due to observed cementing agents in X-ray diffraction (XRD) and scanning electron microscopy (SEM). Adverse effect of ettringite mineral on UCS caused by sodium sulfate addition was suppressed with the combination of 20% NP and 2% PF in lime-stabilized GS. Binding forces from lime and NP resisted to ettringite expansion. Sensitivity of UCS to sulfate effect was more pronounced with sodium sulfate than calcium sulfate. In addition, NP–PF mixture in lime-stabilized GS was more effective, improving the strength of expansive soil, especially with sodium sulfate. In conclusion, reinforcement of NP-lime-stabilized expansive soils with PF is an effective method.
{"title":"Strength Improvement Using Polypropylene Fiber as Reinforcement in Natural Pozzolana-lime-stabilized Expansive Clayey Soil Artificially Contaminated by Sulfates","authors":"H. Gadouri, Brahim Mezian","doi":"10.3311/ppci.21388","DOIUrl":"https://doi.org/10.3311/ppci.21388","url":null,"abstract":"This paper aims to assess the behavior of the unconfined compressive strength (UCS) of polypropylene fiber (PF) reinforced natural pozzolana-lime-stabilized expansive grey clayey soil (GS) contaminated by sulfates. Lime (0–8%), natural pozzolana (NP) (0–20%), and PF (0–3%) by dry weight of soil were used. GS was contaminated by different sulfate contents (0-6%) and UCS was assessed at various curing periods (7–120 days). Results showed that adding 8% lime alone or with 20% NP considerably improved UCS. Including 1% or 2% PF as reinforcement without sulfates in lime-stabilized GS transferred stress from GS to PF due to bonding. However, increasing PF beyond 2% formed lumps, reducing contact and friction coefficient, thus decreasing UCS. This means that the optimum PF dosage was found to be 2%. The UCS of GS increased with PF content up to 2% and then decreased. The UCS significantly increased with higher calcium sulfate content and curing period due to observed cementing agents in X-ray diffraction (XRD) and scanning electron microscopy (SEM). Adverse effect of ettringite mineral on UCS caused by sodium sulfate addition was suppressed with the combination of 20% NP and 2% PF in lime-stabilized GS. Binding forces from lime and NP resisted to ettringite expansion. Sensitivity of UCS to sulfate effect was more pronounced with sodium sulfate than calcium sulfate. In addition, NP–PF mixture in lime-stabilized GS was more effective, improving the strength of expansive soil, especially with sodium sulfate. In conclusion, reinforcement of NP-lime-stabilized expansive soils with PF is an effective method.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72466614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bahareh Katebi, A. Ghalandarzadeh, M. Derakhshandi, N. Ganjian
Structures located on sandy soils can be significantly damaged by earthquake-induced liquefaction. A series of stress-controlled cyclic triaxial tests under harmonic and irregular loading under various soil densities 30%, and 50%, was conducted to evaluate the effects of irregularities and relative densities on the liquefaction characteristics of saturated sand. The irregular actual ground motions time histories obtained from six stations of the 1999 Chi-Chi Earthquake and harmonic sinusoidal cyclic loading time histories were applied to Firoozkooh #161 sand specimens, and the results were compared in terms of the type waveforms loading and relative densities. Based on the stress and energy method, the Correction coefficient is calculated for a variety of densities and types of irregular loading. The present results reveal that it is not precise to assume a single correction coefficient for all records, regardless of the complicated time-domain characteristics of ground motions. Furthermore, the results indicate that the relative soil density and the type of irregular loading influenced sand's pore pressure generation and liquefaction potential.
{"title":"The Effect of Irregular Seismic Loading and Soil Density on the Liquefaction Behavior of Saturated Sand","authors":"Bahareh Katebi, A. Ghalandarzadeh, M. Derakhshandi, N. Ganjian","doi":"10.3311/ppci.21846","DOIUrl":"https://doi.org/10.3311/ppci.21846","url":null,"abstract":"Structures located on sandy soils can be significantly damaged by earthquake-induced liquefaction. A series of stress-controlled cyclic triaxial tests under harmonic and irregular loading under various soil densities 30%, and 50%, was conducted to evaluate the effects of irregularities and relative densities on the liquefaction characteristics of saturated sand. The irregular actual ground motions time histories obtained from six stations of the 1999 Chi-Chi Earthquake and harmonic sinusoidal cyclic loading time histories were applied to Firoozkooh #161 sand specimens, and the results were compared in terms of the type waveforms loading and relative densities. Based on the stress and energy method, the Correction coefficient is calculated for a variety of densities and types of irregular loading. The present results reveal that it is not precise to assume a single correction coefficient for all records, regardless of the complicated time-domain characteristics of ground motions. Furthermore, the results indicate that the relative soil density and the type of irregular loading influenced sand's pore pressure generation and liquefaction potential.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82505289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The main reasons for the success of using chaos maps in meta-heuristic algorithms are fast optimization of non-linear and non-convex problems. One of these cases is the control of the natural frequencies of structures to prevent the destructive and dangerous phenomenon of resonance. Natural frequencies have useful information about the dynamic behavior of structures, and by applying dynamic constraints, a significant improvement is achieved in the optimal design of structural weight. Applying frequency limits with traditional and gradient-based methods is very difficult and time-consuming, and in most cases, the calculation process stops at local optima. Recent research shows that chaos maps play a major role in escaping from local optima and reaching global optima. By combining these maps with meta- heuristic algorithms, while avoiding premature convergence, the access to global optima is accelerated and improved, and the ideal state of balance between the exploration and exploitation stages is realized. Today, chaotic algorithms are widely accepted by researchers and are considered as a challenging topic. In a recent research, six chaotic meta- heuristic algorithms have been investigated for the formation and improvement of results with the optimal design of truss structures. In this part the chaotic algorithms include Chaotic Water Evaporation Optimization (CWEO), Chaotic Tug-of-War Optimization (CTWO) and Chaotic Thermal Exchange Optimization (CTEO) are examined.
{"title":"Comparison of Three Chaotic Meta-heuristic Algorithms for the Optimal Design of Truss Structures with Frequency Constraints","authors":"A. Kaveh, H. Yousefpour","doi":"10.3311/ppci.22594","DOIUrl":"https://doi.org/10.3311/ppci.22594","url":null,"abstract":"The main reasons for the success of using chaos maps in meta-heuristic algorithms are fast optimization of non-linear and non-convex problems. One of these cases is the control of the natural frequencies of structures to prevent the destructive and dangerous phenomenon of resonance. Natural frequencies have useful information about the dynamic behavior of structures, and by applying dynamic constraints, a significant improvement is achieved in the optimal design of structural weight. Applying frequency limits with traditional and gradient-based methods is very difficult and time-consuming, and in most cases, the calculation process stops at local optima. Recent research shows that chaos maps play a major role in escaping from local optima and reaching global optima. By combining these maps with meta- heuristic algorithms, while avoiding premature convergence, the access to global optima is accelerated and improved, and the ideal state of balance between the exploration and exploitation stages is realized. Today, chaotic algorithms are widely accepted by researchers and are considered as a challenging topic. In a recent research, six chaotic meta- heuristic algorithms have been investigated for the formation and improvement of results with the optimal design of truss structures. In this part the chaotic algorithms include Chaotic Water Evaporation Optimization (CWEO), Chaotic Tug-of-War Optimization (CTWO) and Chaotic Thermal Exchange Optimization (CTEO) are examined.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83848409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. K. Sahis, P. Biswas, Sanjib Sadhukhan, Geetam Saha
Present paper deals with the development of a Mechanistic-Empirical model of the strain-based design of perpetual road pavement using Odemark's principle. The bituminous pavement which can withstand minimum design traffic of 300 msa has been classified as perpetual pavement in this paper. The pavement has been considered as a three-layered system with a top layer of bituminous mix followed by unbound granular materials which rest on soil subgrade. The constituent bituminous layer thickness in the pavement has been determined by limiting the radial tensile strain at the bottom of the bituminous layer against fatigue and the vertical compressive strain at the top of the subgrade against rutting. The allowable strain against rutting and fatigue has been used in the present analysis from mechanistic-empirical correlations recommended in IRC:37-2018. The pavement section has been transformed into a homogeneous system by Odemark's method for application of Boussinesq's theory. To validate the thickness of the perpetual pavement, the strain at different layer interfaces in the pavement was compared using IITPAVE software, which shows the pavement section using present method is safe against rutting but marginally fails under fatigue. Moreover, conventional pavement thickness obtained using IRC:37-2018 were compared with the present method, which shows reasonably good convergence. It has been found that the bituminous layer thickness in a layered system of pavement seems to be more sensitive to fatigue than rutting. In this backdrop, modified fatigue and rutting strain values have been recommended for the design of perpetual road pavement.
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