Pub Date : 2018-12-12DOI: 10.11648/j.ajce.20180605.14
Zenagebriel Gebremedhn, Guofu Qiao, Jilong Li
This paper presents the finite element results of a parametric investigation of the U-shaped box culvert of prefabricated reinforced concrete subject to loading conditions. It was included outer size span length 4.80m, rise of 4.80m, laying width 1.5m and 0.4m slab and wall thickness. Its components consisted of two symmetrical u-shaped structures joined together using the tip at the end of the bell. It was not recommended for areas with excessive settlement where deep foundations were required. The upper and side ground pressure was considered in the culvert, which depends on the depth of the canal. The finite element method has been chosen for purpose of modeling and analyzing the structural behaver of the standard three dimensional solid and wire elements of the u-shaped box culvert under different loading conditions using ABAQUS-V6.14-4 due to its flexibility in creating geometry and material modeling. The culvert has been modeled using 3-D solid (C3D8R) elements reduce integration for concrete and 3-D wire (T3D2H) elements for reinforcement having geometric and material linearity as well as hybrid formulation. The reinforcement was modeled as rebar elements embedded in the surface element. Finally, the Finite element analysis (FEA) results were showed deflection and stress as well as effect of with and without distribution steel on the culvert.
{"title":"Finite Element Modeling and Analysis of Precast Reinforced Concrete U-Shaped Box Culvert Using ABAQUS","authors":"Zenagebriel Gebremedhn, Guofu Qiao, Jilong Li","doi":"10.11648/j.ajce.20180605.14","DOIUrl":"https://doi.org/10.11648/j.ajce.20180605.14","url":null,"abstract":"This paper presents the finite element results of a parametric investigation of the U-shaped box culvert of prefabricated reinforced concrete subject to loading conditions. It was included outer size span length 4.80m, rise of 4.80m, laying width 1.5m and 0.4m slab and wall thickness. Its components consisted of two symmetrical u-shaped structures joined together using the tip at the end of the bell. It was not recommended for areas with excessive settlement where deep foundations were required. The upper and side ground pressure was considered in the culvert, which depends on the depth of the canal. The finite element method has been chosen for purpose of modeling and analyzing the structural behaver of the standard three dimensional solid and wire elements of the u-shaped box culvert under different loading conditions using ABAQUS-V6.14-4 due to its flexibility in creating geometry and material modeling. The culvert has been modeled using 3-D solid (C3D8R) elements reduce integration for concrete and 3-D wire (T3D2H) elements for reinforcement having geometric and material linearity as well as hybrid formulation. The reinforcement was modeled as rebar elements embedded in the surface element. Finally, the Finite element analysis (FEA) results were showed deflection and stress as well as effect of with and without distribution steel on the culvert.","PeriodicalId":7606,"journal":{"name":"American Journal of Civil Engineering","volume":"44 1","pages":"162"},"PeriodicalIF":0.0,"publicationDate":"2018-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74723731","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 : 2018-11-28DOI: 10.11648/J.AJCE.20180605.13
Anteneh Geremew, Basha Fayissa
Expansive soil refers to a particular type of soils – almost clayey soils in property - that expand as they absorb water and shrink when they dry out. The process of swelling generates pressures that can cause lifting, or heaving of structures whilst shrinkage process can cause differential settlement on civil structure. A large number of buildings and roads are placed on such type of soil and exposed to the danger from this swelling and shrinkage processes. In order to avoid the previous mentioned risk from the expansive soil, a technique of soil stabilization should be made for this type of soil to enhance some of its properties. In this study, the experimental investigations have been made to study the suitability of natural gravel from jiren quarry site to improve properties of expansive soil. The important parameters to be determine the geo-technical properties such as Specific gravity, Liquid limit, Plastic limit, Plasticity index, dry density and California Bearing (CBR) ratio values. According to ERA 2002 this type of soils is poor for subgrade for road construction. In order to realize the desired objective, a purposive sampling technique which is non –probability method was adopted in order to collect disturbed soil samples at depth of 1.5m and natural gravel from jiren quarry site used for the preparation of different laboratory tests. The laboratory work involved sieve analysis along with consistence test to classify the soil sample. The preliminary investigation of the soil shows that it belongs to A-7-5 class of soil in AASHTO and CH in USCS soil classification system. Soils under this class are generally of poor for subgrade road construction. Atterberg limits, compaction and CBR tests were used to evaluate properties of stabilized soil. The soil was stabilized with natural gravel in stepped concentration of 5%, 10%, 15%, 20% and 25% by dry weight of the soil. Analysis of the results shows the addition of natural gravel improve the geotechnical properties of the expansive black cotton soil. The addition of natural gravel reduces plasticity index, swelling and OMC with an increase in MDD and CBR with all increased natural gravel contents. The addition of 20% and 25% of natural gravel established an increased CBR value by 670% and 958% respectively, indicating the subgrade class falling under S4 and S5 respectively. From this study it was found out that natural gravel stabilized with soil do meet the minimum requirement of ERA pavement manual specification for use as a sub-grade material in road construction.
{"title":"Experimental Performance Studies on the Improved Expansive Subgrade Soil Formation by Using Mechanical Stabilization with Natural Gravel Around Jimma Quarry Sites","authors":"Anteneh Geremew, Basha Fayissa","doi":"10.11648/J.AJCE.20180605.13","DOIUrl":"https://doi.org/10.11648/J.AJCE.20180605.13","url":null,"abstract":"Expansive soil refers to a particular type of soils – almost clayey soils in property - that expand as they absorb water and shrink when they dry out. The process of swelling generates pressures that can cause lifting, or heaving of structures whilst shrinkage process can cause differential settlement on civil structure. A large number of buildings and roads are placed on such type of soil and exposed to the danger from this swelling and shrinkage processes. In order to avoid the previous mentioned risk from the expansive soil, a technique of soil stabilization should be made for this type of soil to enhance some of its properties. In this study, the experimental investigations have been made to study the suitability of natural gravel from jiren quarry site to improve properties of expansive soil. The important parameters to be determine the geo-technical properties such as Specific gravity, Liquid limit, Plastic limit, Plasticity index, dry density and California Bearing (CBR) ratio values. According to ERA 2002 this type of soils is poor for subgrade for road construction. In order to realize the desired objective, a purposive sampling technique which is non –probability method was adopted in order to collect disturbed soil samples at depth of 1.5m and natural gravel from jiren quarry site used for the preparation of different laboratory tests. The laboratory work involved sieve analysis along with consistence test to classify the soil sample. The preliminary investigation of the soil shows that it belongs to A-7-5 class of soil in AASHTO and CH in USCS soil classification system. Soils under this class are generally of poor for subgrade road construction. Atterberg limits, compaction and CBR tests were used to evaluate properties of stabilized soil. The soil was stabilized with natural gravel in stepped concentration of 5%, 10%, 15%, 20% and 25% by dry weight of the soil. Analysis of the results shows the addition of natural gravel improve the geotechnical properties of the expansive black cotton soil. The addition of natural gravel reduces plasticity index, swelling and OMC with an increase in MDD and CBR with all increased natural gravel contents. The addition of 20% and 25% of natural gravel established an increased CBR value by 670% and 958% respectively, indicating the subgrade class falling under S4 and S5 respectively. From this study it was found out that natural gravel stabilized with soil do meet the minimum requirement of ERA pavement manual specification for use as a sub-grade material in road construction.","PeriodicalId":7606,"journal":{"name":"American Journal of Civil Engineering","volume":"14 1","pages":"154"},"PeriodicalIF":0.0,"publicationDate":"2018-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86828686","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 : 2018-11-26DOI: 10.11648/J.AJCE.20180605.12
A. Rahaman, Asif Mostafa Anik, N. Serker
Column plays very important role in reinforced concrete building as total load is transferred through column. When rectangular columns are used in structure, columns can protrude out of the walls and corners which reduce aesthetic view of structure. Concrete structures with specially shaped columns has been found out as a solution of this problem. Not only for aesthetical point of view but also for structural aspect, specially shaped columns perform well. The aim of this study is to evaluate the comparative lateral load resistance capacity of buildings with rectangular columns and buildings with specially shaped columns. Four different buildings (i.e. 6 storey, 10 storey, 15 storey and 20 storey) are analysed with conventional rectangular columns and same buildings are analysed with specially shaped (i.e. L, Tee, cross) columns with same equivalent cross section area as of rectangular columns. In this paper, at first, the proposed buildings are analysed with linear static analysis and Secondly, linear dynamic analysis. From analysis results, it has been found that maximum storey displacements of all building models i.e. 6, 10, 15 & 20 storeys are under acceptable limit for both rectangular and special shaped columns. For rectangular shaped column building, displacement increases 11.78%, 8.83% & 34.84% & 5.51% respectively for 6, 10, 15 & 20 storeys building compared with building with special shaped columns. After analysis and comparison it is concluded that the buildings with specially shaped columns perform better under lateral load conditions than the buildings with conventional rectangular columns under the same loadings.
{"title":"Effect of Special Shaped Column on Lateral Load Resistance Capacity of Reinforced Concrete (RC) Building","authors":"A. Rahaman, Asif Mostafa Anik, N. Serker","doi":"10.11648/J.AJCE.20180605.12","DOIUrl":"https://doi.org/10.11648/J.AJCE.20180605.12","url":null,"abstract":"Column plays very important role in reinforced concrete building as total load is transferred through column. When rectangular columns are used in structure, columns can protrude out of the walls and corners which reduce aesthetic view of structure. Concrete structures with specially shaped columns has been found out as a solution of this problem. Not only for aesthetical point of view but also for structural aspect, specially shaped columns perform well. The aim of this study is to evaluate the comparative lateral load resistance capacity of buildings with rectangular columns and buildings with specially shaped columns. Four different buildings (i.e. 6 storey, 10 storey, 15 storey and 20 storey) are analysed with conventional rectangular columns and same buildings are analysed with specially shaped (i.e. L, Tee, cross) columns with same equivalent cross section area as of rectangular columns. In this paper, at first, the proposed buildings are analysed with linear static analysis and Secondly, linear dynamic analysis. From analysis results, it has been found that maximum storey displacements of all building models i.e. 6, 10, 15 & 20 storeys are under acceptable limit for both rectangular and special shaped columns. For rectangular shaped column building, displacement increases 11.78%, 8.83% & 34.84% & 5.51% respectively for 6, 10, 15 & 20 storeys building compared with building with special shaped columns. After analysis and comparison it is concluded that the buildings with specially shaped columns perform better under lateral load conditions than the buildings with conventional rectangular columns under the same loadings.","PeriodicalId":7606,"journal":{"name":"American Journal of Civil Engineering","volume":"61 1","pages":"147"},"PeriodicalIF":0.0,"publicationDate":"2018-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88793742","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 : 2018-11-15DOI: 10.11648/J.AJCE.20180605.11
Tarekegn Kumela
Road building in Ethiopia is increasingly in demand to meet medium and long terms development programs. Roads are constructed radiating from the capital city of the country in all direction. The objective of this research study is to evaluate the flexible pavement deflections with respect to pavement depth using Software along Jimma to Seka road segment and compare the laboratory results with the Ethiopian Road Authority (ERA) standards. Ever Stress Software (ESS) is a numerical analysis technique to obtain the deflection of pavement layers. The methodology of this research was finding the sensitivity of the road parameters (dimension, layers thickness, elastic modulus, Poisson’s ratio, loads and pressures) in reducing the major causes of failure in asphalt pavement fatigue cracking and rutting due to vertical surface deflections, the critical tensile strains at the bottom of the asphalt layer and the critical compressive strains on the top of subgrade. The analytical method used was the elastic modulus and Poisson’s ratio of the pavement materials as design parameters after CBR results of each layers was obtained. The expected outputs have shown that the displacement or deflection (u z ) was as high as 0.38mm in the asphalt surface and gradually decreased as the pavement thickness increased. Large values of deflections indicates an over stressed condition which results in the pavement surface to crack and distortion as a results of fatigue or accumulated plastic deformation. Therefore, the relative deflection of pavement layer decreases as the pavement depth increases.
{"title":"Evaluation of Flexible Pavement Deflections with Respect to Pavement Depths Using Software (A Case Study Jimma to Seka Road)","authors":"Tarekegn Kumela","doi":"10.11648/J.AJCE.20180605.11","DOIUrl":"https://doi.org/10.11648/J.AJCE.20180605.11","url":null,"abstract":"Road building in Ethiopia is increasingly in demand to meet medium and long terms development programs. Roads are constructed radiating from the capital city of the country in all direction. The objective of this research study is to evaluate the flexible pavement deflections with respect to pavement depth using Software along Jimma to Seka road segment and compare the laboratory results with the Ethiopian Road Authority (ERA) standards. Ever Stress Software (ESS) is a numerical analysis technique to obtain the deflection of pavement layers. The methodology of this research was finding the sensitivity of the road parameters (dimension, layers thickness, elastic modulus, Poisson’s ratio, loads and pressures) in reducing the major causes of failure in asphalt pavement fatigue cracking and rutting due to vertical surface deflections, the critical tensile strains at the bottom of the asphalt layer and the critical compressive strains on the top of subgrade. The analytical method used was the elastic modulus and Poisson’s ratio of the pavement materials as design parameters after CBR results of each layers was obtained. The expected outputs have shown that the displacement or deflection (u z ) was as high as 0.38mm in the asphalt surface and gradually decreased as the pavement thickness increased. Large values of deflections indicates an over stressed condition which results in the pavement surface to crack and distortion as a results of fatigue or accumulated plastic deformation. Therefore, the relative deflection of pavement layer decreases as the pavement depth increases.","PeriodicalId":7606,"journal":{"name":"American Journal of Civil Engineering","volume":"152 1","pages":"141"},"PeriodicalIF":0.0,"publicationDate":"2018-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78868081","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 : 2018-11-08DOI: 10.11648/j.ajce.20180604.14
Z. Miao, Z. Fang
To investigate the shear performance of the interface between concrete and stone, the interfacial shear test of concrete - stone carried out by using the Z-type and hoop-type specimens. The effects of different bonding methods, material strength and different forms of embedded steel bars on interfacial shear properties are considered.. The experimental results show that the bonding interface between concrete and stone is the weak point of the sample, and the damage occurs on the interface. The fracture pattern of Z-type specimen is vertical crack and diagonal crack near the interface. The crack forms of the hoop type specimens are the diagonal cracks distributed on the top of concrete, vertical and oblique cracks on the sides. Within a certain range, the strength g of the concrete will increase the shear strength of the interface and delay the cracking of the specimen. When the strength grades of concrete were C35, C40 and C45, the shear strength of the Z-type specimen increased by 14.7% and 10.8% respectively, and the shear strength of the hoop-type specimen increased by 15.2% and 11.1% respectively. Interfacial implantable steel bar can improve the shear resistance of interface significantly, and the greater the rate of steel bar, the greater the shear strength. When the planting rates were 0%, 0.196%, 0.392% and 0.785% respectively, the improvement rates of shear strength of Z-type specimens were 40.2%, 65.5% and 45.2% respectively, and the improvement rates of shear strength of hoop specimens were 64.1%, 54.5% and 60.5% respectively. The shear strength of the hoop type specimen is greater than that of the Z-type specimen, the non-planted bar specimen is increased by about 20%, and the planted steel bar specimen is increased by about 40% to 55%.
{"title":"Experimental Study on Interfacial Shear Properties of Concrete Reinforced Stone Arch Bridges","authors":"Z. Miao, Z. Fang","doi":"10.11648/j.ajce.20180604.14","DOIUrl":"https://doi.org/10.11648/j.ajce.20180604.14","url":null,"abstract":"To investigate the shear performance of the interface between concrete and stone, the interfacial shear test of concrete - stone carried out by using the Z-type and hoop-type specimens. The effects of different bonding methods, material strength and different forms of embedded steel bars on interfacial shear properties are considered.. The experimental results show that the bonding interface between concrete and stone is the weak point of the sample, and the damage occurs on the interface. The fracture pattern of Z-type specimen is vertical crack and diagonal crack near the interface. The crack forms of the hoop type specimens are the diagonal cracks distributed on the top of concrete, vertical and oblique cracks on the sides. Within a certain range, the strength g of the concrete will increase the shear strength of the interface and delay the cracking of the specimen. When the strength grades of concrete were C35, C40 and C45, the shear strength of the Z-type specimen increased by 14.7% and 10.8% respectively, and the shear strength of the hoop-type specimen increased by 15.2% and 11.1% respectively. Interfacial implantable steel bar can improve the shear resistance of interface significantly, and the greater the rate of steel bar, the greater the shear strength. When the planting rates were 0%, 0.196%, 0.392% and 0.785% respectively, the improvement rates of shear strength of Z-type specimens were 40.2%, 65.5% and 45.2% respectively, and the improvement rates of shear strength of hoop specimens were 64.1%, 54.5% and 60.5% respectively. The shear strength of the hoop type specimen is greater than that of the Z-type specimen, the non-planted bar specimen is increased by about 20%, and the planted steel bar specimen is increased by about 40% to 55%.","PeriodicalId":7606,"journal":{"name":"American Journal of Civil Engineering","volume":"72 1","pages":"134"},"PeriodicalIF":0.0,"publicationDate":"2018-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85965677","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 : 2018-10-18DOI: 10.11648/j.ajce.20180604.13
Lv Jing, Y. Tianjiao
With the continuous development of the social economy, the city has a chaotic image of unwarranted expansion, so the proposal of compact cities and stock planning has been very important. Land for public service facilities is a major component of urban functional land, so it can be used to reflect the compactness of urban land. Based on the background of compact city, this paper analyzed the service efficiency of public service facilities land in Changchun City, including land for educational and cultural facilities, sports facilities, medical and health facilities and social welfare facilities. Through GIS and other technical means to process the data, and comprehensive analysis of the number of facilities, spatial distribution and accessibility analysis, the results of spatial allocation were obtained. In order to consider the behavioral factors of human beings, these results were divided into suppliers, suppliers and demanders for comparative analysis, and the influencing factors and their interrelationships leading to these results were obtained. At the same time, this gave specific suggestions on regional control, spatial structure compactness and spatial element allocation from the macro, meso and micro levels. Furthermore, it will give the relevant planning department measures and recommendations about optimizing the space efficiency of land use for public service facilities.
{"title":"Research on Optimization of Public Service Facilities Land Efficiency in Changchun City Based on Compact City","authors":"Lv Jing, Y. Tianjiao","doi":"10.11648/j.ajce.20180604.13","DOIUrl":"https://doi.org/10.11648/j.ajce.20180604.13","url":null,"abstract":"With the continuous development of the social economy, the city has a chaotic image of unwarranted expansion, so the proposal of compact cities and stock planning has been very important. Land for public service facilities is a major component of urban functional land, so it can be used to reflect the compactness of urban land. Based on the background of compact city, this paper analyzed the service efficiency of public service facilities land in Changchun City, including land for educational and cultural facilities, sports facilities, medical and health facilities and social welfare facilities. Through GIS and other technical means to process the data, and comprehensive analysis of the number of facilities, spatial distribution and accessibility analysis, the results of spatial allocation were obtained. In order to consider the behavioral factors of human beings, these results were divided into suppliers, suppliers and demanders for comparative analysis, and the influencing factors and their interrelationships leading to these results were obtained. At the same time, this gave specific suggestions on regional control, spatial structure compactness and spatial element allocation from the macro, meso and micro levels. Furthermore, it will give the relevant planning department measures and recommendations about optimizing the space efficiency of land use for public service facilities.","PeriodicalId":7606,"journal":{"name":"American Journal of Civil Engineering","volume":"38 1","pages":"123"},"PeriodicalIF":0.0,"publicationDate":"2018-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73742566","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 : 2018-09-18DOI: 10.11648/J.AJCE.20180604.12
Jia Lee, Junqi Lin, Jinlong Liu
In this article, based on the earthquake damage data of ‘5.12’ Wenchuan Earthquake and the improved method of earthquake damage prediction of highway subgrade and pavement which is obtained by using nonlinear regression method, a new method using closeness degree is given. This new method uses fuzzy recognition to determine the earthquake damage level of certain road section. In order to conduct fuzzy recognition, the membership function of the fuzzy set of the damage grade is also given, after conducting fuzzy recognition for membership function of earthquake damage using closeness degree method, the earthquake damage prediction results of corresponding road sections will be obtained. Finally, an example is given based on the data of earthquake damage in Wenchuan earthquake. The results of the example show that this new method of earthquake damage prediction using closeness degree indeed has higher accuracy, which proves it another effective and practical method for earthquake damage prediction of highway pavement and subgrade. This method also provides a reference for future research on related projects.
{"title":"An Improved Method for Earthquake Damage Prediction of Highway Subgrade and Pavement Based on Closeness Degree Method","authors":"Jia Lee, Junqi Lin, Jinlong Liu","doi":"10.11648/J.AJCE.20180604.12","DOIUrl":"https://doi.org/10.11648/J.AJCE.20180604.12","url":null,"abstract":"In this article, based on the earthquake damage data of ‘5.12’ Wenchuan Earthquake and the improved method of earthquake damage prediction of highway subgrade and pavement which is obtained by using nonlinear regression method, a new method using closeness degree is given. This new method uses fuzzy recognition to determine the earthquake damage level of certain road section. In order to conduct fuzzy recognition, the membership function of the fuzzy set of the damage grade is also given, after conducting fuzzy recognition for membership function of earthquake damage using closeness degree method, the earthquake damage prediction results of corresponding road sections will be obtained. Finally, an example is given based on the data of earthquake damage in Wenchuan earthquake. The results of the example show that this new method of earthquake damage prediction using closeness degree indeed has higher accuracy, which proves it another effective and practical method for earthquake damage prediction of highway pavement and subgrade. This method also provides a reference for future research on related projects.","PeriodicalId":7606,"journal":{"name":"American Journal of Civil Engineering","volume":"111 1","pages":"118"},"PeriodicalIF":0.0,"publicationDate":"2018-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79303994","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 : 2018-09-14DOI: 10.11648/J.AJCE.20180604.11
D. Xiaoyan, Yangsheng Ye, Qian-li Zhang, Degou Cai
To address the adverse effects of the frost heaving of subgrades in regions with seasonal frozen soil on the smoothness of high-speed railway tracks, the effects of several factors—including filler, water content and external loading—on a micro-frost-heaving (MFH) filling material were studied through laboratory experiments and theoretical analysis. In addition, the interaction mechanism between the filler and skeleton particles during the frost heaving process was analyzed. The results show the following: The MFH filling material was composed of a coarse-grained skeleton, a filler between skeleton particles and the remaining unfilled voids. When the filling ratio of the filler was 0.25, the filling material underwent initial macroscopic frost heaving. An overlying load could inhibit the filling material from frost heaving. During the frost heaving process, the volume of coarse skeleton particles with high stiffness remained almost unchanged, whereas the filler expanded in volume and thus filled the remaining voids between skeleton particles and lifted the skeleton particles, resulting in macroscopic frost heaving of the filling material. When their ratio was relatively high, the remaining voids between skeleton particles had a strong absorptivity and weakened the capacity of the filler to lift the skeleton particles. The filler raised the skeleton particles, resulting in an increase in the gaps between them, which in turn facilitated the filling action of the filler. When the skeleton structure was stable, the filling action of the filler was more pronounced. The frost heaving of an MFH filling material is in fact a dynamic equilibrium process between the filling and lifting actions of the filler.
{"title":"Interaction Mechanism of the Frost Heaving of the Filler and Skeleton Particles in a Micro-Frost-Heaving Filling Material","authors":"D. Xiaoyan, Yangsheng Ye, Qian-li Zhang, Degou Cai","doi":"10.11648/J.AJCE.20180604.11","DOIUrl":"https://doi.org/10.11648/J.AJCE.20180604.11","url":null,"abstract":"To address the adverse effects of the frost heaving of subgrades in regions with seasonal frozen soil on the smoothness of high-speed railway tracks, the effects of several factors—including filler, water content and external loading—on a micro-frost-heaving (MFH) filling material were studied through laboratory experiments and theoretical analysis. In addition, the interaction mechanism between the filler and skeleton particles during the frost heaving process was analyzed. The results show the following: The MFH filling material was composed of a coarse-grained skeleton, a filler between skeleton particles and the remaining unfilled voids. When the filling ratio of the filler was 0.25, the filling material underwent initial macroscopic frost heaving. An overlying load could inhibit the filling material from frost heaving. During the frost heaving process, the volume of coarse skeleton particles with high stiffness remained almost unchanged, whereas the filler expanded in volume and thus filled the remaining voids between skeleton particles and lifted the skeleton particles, resulting in macroscopic frost heaving of the filling material. When their ratio was relatively high, the remaining voids between skeleton particles had a strong absorptivity and weakened the capacity of the filler to lift the skeleton particles. The filler raised the skeleton particles, resulting in an increase in the gaps between them, which in turn facilitated the filling action of the filler. When the skeleton structure was stable, the filling action of the filler was more pronounced. The frost heaving of an MFH filling material is in fact a dynamic equilibrium process between the filling and lifting actions of the filler.","PeriodicalId":7606,"journal":{"name":"American Journal of Civil Engineering","volume":"8 1","pages":"109"},"PeriodicalIF":0.0,"publicationDate":"2018-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88191986","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 : 2018-06-27DOI: 10.11648/j.ajce.20180603.13
Hui Liao, K. Han, Shuo Sun, Yajing Jin
In recent years, the ever-changing climate has caused natural disasters in various countries to occur frequently. Climate change has become one of the factors that have caused this country to be vulnerable. This article mainly quantitatively studies how climate change affects regional instability. A comprehensive indicator evaluation method is used to establish a PSA model. The country's vulnerability is defined in terms of the dimensions of pressure, sensitivity, and adaptive capability. This article selected Philippines as the research object, and based on the data processing by PSA model, we obtained the Fragile State Index (FSI) of Philippines in the past ten years. It has found that the flooding in 2012 has made it more vulnerable to Philippines and the results of the analysis are in line with the actual situation. Then, the K-means clustering algorithm is used to get a tipping point (0.5) that can define whether it is fragile or not. What's more, the critical point is verified to be reasonable. Finally, under the guidance of the data of the three dimensions and first-class indicators, the intervention measures that the country should take to address climate change are proposed to reduce regional instability.
{"title":"The Evaluation of Regional Instability to Climate Change Based on the PSA Model—A Case Study of Philippines","authors":"Hui Liao, K. Han, Shuo Sun, Yajing Jin","doi":"10.11648/j.ajce.20180603.13","DOIUrl":"https://doi.org/10.11648/j.ajce.20180603.13","url":null,"abstract":"In recent years, the ever-changing climate has caused natural disasters in various countries to occur frequently. Climate change has become one of the factors that have caused this country to be vulnerable. This article mainly quantitatively studies how climate change affects regional instability. A comprehensive indicator evaluation method is used to establish a PSA model. The country's vulnerability is defined in terms of the dimensions of pressure, sensitivity, and adaptive capability. This article selected Philippines as the research object, and based on the data processing by PSA model, we obtained the Fragile State Index (FSI) of Philippines in the past ten years. It has found that the flooding in 2012 has made it more vulnerable to Philippines and the results of the analysis are in line with the actual situation. Then, the K-means clustering algorithm is used to get a tipping point (0.5) that can define whether it is fragile or not. What's more, the critical point is verified to be reasonable. Finally, under the guidance of the data of the three dimensions and first-class indicators, the intervention measures that the country should take to address climate change are proposed to reduce regional instability.","PeriodicalId":7606,"journal":{"name":"American Journal of Civil Engineering","volume":"126 1","pages":"99"},"PeriodicalIF":0.0,"publicationDate":"2018-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88175850","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 : 2018-06-26DOI: 10.11648/J.AJCE.20180603.12
S. M. R. Shah, N. Zainuddin, Y. H. Min, N. A. N. Nasaruddin, Tey Li Sian
Using plastic as additive in pavement has gained popularity for the past several years. Plastics waste is a serious environmental issue due to its non-biodegradable properties and hard to be disposed. There is a high demand of plastics in the industries as a packaging and disposable consumer items due to its inexpensive, lightweight and durable properties. Polyethylene (PE) has been extensively used in packaging, pipes, toys, garbage bags and bottles. The purpose of this study is to evaluate the properties of PE modified bituminous mixture in comparison to conventional bituminous mixture. This study utilized both High Density Polyethylene (HDPE) and Low Density Polyethylene (LDPE) granules in order to achieve optimum benefits. Wearing course samples were prepared using Marshall Mix design method and according to Standard Specification for Road Works as guidelines. Laboratory study was performed on the compacted mixtures to determine the optimum bitumen content (OBC) and evaluate the effect of PE on its properties. The modified mixes show promising results: higher stability and lower optimum bitumen content (OBC) when compared to a conventional mix. The results indicate that the addition of 2% Polyethylene by weight of aggregate reduce the amount of OBC by 4.2%. Hence, Polyethylene modified bituminous mixture not only can helps reduce the waste plastics but also results in saving in pavement material costs.
{"title":"Reduction of Optimum Bitumen Content in Polyethylene Modified Bituminous Mixes","authors":"S. M. R. Shah, N. Zainuddin, Y. H. Min, N. A. N. Nasaruddin, Tey Li Sian","doi":"10.11648/J.AJCE.20180603.12","DOIUrl":"https://doi.org/10.11648/J.AJCE.20180603.12","url":null,"abstract":"Using plastic as additive in pavement has gained popularity for the past several years. Plastics waste is a serious environmental issue due to its non-biodegradable properties and hard to be disposed. There is a high demand of plastics in the industries as a packaging and disposable consumer items due to its inexpensive, lightweight and durable properties. Polyethylene (PE) has been extensively used in packaging, pipes, toys, garbage bags and bottles. The purpose of this study is to evaluate the properties of PE modified bituminous mixture in comparison to conventional bituminous mixture. This study utilized both High Density Polyethylene (HDPE) and Low Density Polyethylene (LDPE) granules in order to achieve optimum benefits. Wearing course samples were prepared using Marshall Mix design method and according to Standard Specification for Road Works as guidelines. Laboratory study was performed on the compacted mixtures to determine the optimum bitumen content (OBC) and evaluate the effect of PE on its properties. The modified mixes show promising results: higher stability and lower optimum bitumen content (OBC) when compared to a conventional mix. The results indicate that the addition of 2% Polyethylene by weight of aggregate reduce the amount of OBC by 4.2%. Hence, Polyethylene modified bituminous mixture not only can helps reduce the waste plastics but also results in saving in pavement material costs.","PeriodicalId":7606,"journal":{"name":"American Journal of Civil Engineering","volume":"147 1","pages":"93"},"PeriodicalIF":0.0,"publicationDate":"2018-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91303267","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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