Pub Date : 2018-08-30DOI: 10.31814/10.31814/stce.nuce2018-12(5)-08
N. Minh
Sustainability is a holistic concept in development studies, including urban studies, encompassing natural, technical and social aspects, and has been regarded as an ultimate goal for every nation to strive for as well as for every community to achieve in the context of global climate change, environmental crisis and social instability caused by various socio-economic factors. In addition to theoretical investigation, going for social sustainability in practice requires a well prepared action programme which should begin with learning from international experience (especially when it comes to such a new and superior development concept as social sustainability), understanding both the strengths and the weaknesses, and finding new driving forces. Given that a neighbourhood is a miniature (and a complete unit) of a city, social sustainability may be considered and experimented at the local level first. This proves to be a simpler task to fulfil, a more practical approach to a rather complex issue and a wise option to make. The author aims to analyse some of the world’s best examples before reviewing the current potentials and then comes up with a number of suggestions for the first cornerstones of the future society that will be mainly established on the basis of humanity with core social values and good individual opportunities offered to all citizens. Keywords: social sustainability; sustainable city; neighbourhood.
{"title":"Towards a socially sustainable city concept in Vietnam - international experience, local policy making and preparatory steps","authors":"N. Minh","doi":"10.31814/10.31814/stce.nuce2018-12(5)-08","DOIUrl":"https://doi.org/10.31814/10.31814/stce.nuce2018-12(5)-08","url":null,"abstract":"Sustainability is a holistic concept in development studies, including urban studies, encompassing natural, technical and social aspects, and has been regarded as an ultimate goal for every nation to strive for as well as for every community to achieve in the context of global climate change, environmental crisis and social instability caused by various socio-economic factors. In addition to theoretical investigation, going for social sustainability in practice requires a well prepared action programme which should begin with learning from international experience (especially when it comes to such a new and superior development concept as social sustainability), understanding both the strengths and the weaknesses, and finding new driving forces. Given that a neighbourhood is a miniature (and a complete unit) of a city, social sustainability may be considered and experimented at the local level first. This proves to be a simpler task to fulfil, a more practical approach to a rather complex issue and a wise option to make. The author aims to analyse some of the world’s best examples before reviewing the current potentials and then comes up with a number of suggestions for the first cornerstones of the future society that will be mainly established on the basis of humanity with core social values and good individual opportunities offered to all citizens. \u0000Keywords: social sustainability; sustainable city; neighbourhood.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89535823","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 : 2018-08-30DOI: 10.31814/stce.nuce2018-12(5)-06
L. Ha, L. Hung, L. Q. Trung
The current trend of increasing construction project size and complexity results in higher level of project risk. As a result, risk management is a crucial determinant of the success of a project. It seems necessary for construction companies to integrate a risk management system into their organizational structure. The main aim of this paper is to propose a risk assessment framework using Artificial Neural Network (ANN) technique. Three main phases of the proposed framework are risk management phase, ANN training phase and framework application phase. Thereby, Risk Factors are identified and analysed using Failure Mode and Effect Analysis (FMEA) technique. ANN model is created and trained to evaluate the impact of Risk Factors on Project Risk which is represented through the ratio of contractor’s profit to project costs. As a result, the framework with successful model is used as a tool to support the construction company in assessing risk and evaluate their impact on the project’s profit for new projects. Keywords: risk management; risk assessment; Artificial Neural Network (ANN); Failure Mode and Effect Analysis (FMEA); construction project.
{"title":"A risk assessment framework for construction project using artificial neural network","authors":"L. Ha, L. Hung, L. Q. Trung","doi":"10.31814/stce.nuce2018-12(5)-06","DOIUrl":"https://doi.org/10.31814/stce.nuce2018-12(5)-06","url":null,"abstract":"The current trend of increasing construction project size and complexity results in higher level of project risk. As a result, risk management is a crucial determinant of the success of a project. It seems necessary for construction companies to integrate a risk management system into their organizational structure. The main aim of this paper is to propose a risk assessment framework using Artificial Neural Network (ANN) technique. Three main phases of the proposed framework are risk management phase, ANN training phase and framework application phase. Thereby, Risk Factors are identified and analysed using Failure Mode and Effect Analysis (FMEA) technique. ANN model is created and trained to evaluate the impact of Risk Factors on Project Risk which is represented through the ratio of contractor’s profit to project costs. As a result, the framework with successful model is used as a tool to support the construction company in assessing risk and evaluate their impact on the project’s profit for new projects. \u0000Keywords: risk management; risk assessment; Artificial Neural Network (ANN); Failure Mode and Effect Analysis (FMEA); construction project.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86798018","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 : 2018-08-30DOI: 10.31814/STCE.NUCE2018-12(5)-01
Han Ngoc Duc, V. Tuan, N. T. Dat
The shear transferring mechanisms of shallow-hollow composite beams with concrete slab cast in place are different with conventional headed shear studs and have not been investigated previously. In this study, the behavior and push-out test of concrete dowel connectors for longitudinal shear in shallow-hollow composite beams are described. The theory prediction for concrete dowel connectors without tie-bars adopted in this study was based on EN 1992-1-1 and EN 1994-1-1. Push-out tests of three specimens were conducted and the results were compared with theory prediction and published formula to identify longitudinal shear resistance. The failure of specimens and the ultimate failure load values of push-out test were proved that the behavior of concrete dowel in shallow-hollow composite beams was not under pure shear stress. Keywords: steel-concrete composite beam; shallow-hollow composite beam; concrete dowel connectors; longitudinal shear resistance; shallow floor structure.
{"title":"Behaviour and push-out test of concrete dowel connectors for longitudinal shear in shallow-hollow composite beams","authors":"Han Ngoc Duc, V. Tuan, N. T. Dat","doi":"10.31814/STCE.NUCE2018-12(5)-01","DOIUrl":"https://doi.org/10.31814/STCE.NUCE2018-12(5)-01","url":null,"abstract":"The shear transferring mechanisms of shallow-hollow composite beams with concrete slab cast in place are different with conventional headed shear studs and have not been investigated previously. In this study, the behavior and push-out test of concrete dowel connectors for longitudinal shear in shallow-hollow composite beams are described. The theory prediction for concrete dowel connectors without tie-bars adopted in this study was based on EN 1992-1-1 and EN 1994-1-1. Push-out tests of three specimens were conducted and the results were compared with theory prediction and published formula to identify longitudinal shear resistance. The failure of specimens and the ultimate failure load values of push-out test were proved that the behavior of concrete dowel in shallow-hollow composite beams was not under pure shear stress. \u0000Keywords: steel-concrete composite beam; shallow-hollow composite beam; concrete dowel connectors; longitudinal shear resistance; shallow floor structure.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86914947","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 : 2018-08-30DOI: 10.31814/STCE.NUCE2018-12(5)-13
N. Tâm, Nguyen Thi Lien Huong, Nguyen Bao Ngoc
Labour productivity of Vietnamese economy in general and of Vietnamese construction industry in particular is low in comparison with other countries. Boosting labour productivity is becoming an urgency and is attracting much attention from both domestic and foreign researchers. This paper focuses on a series of factors affecting labour productivity on construction site in Hanoi. The research aims to evaluate and rate the extent of impact of each factor to labour productivity. By referring to the outcomes of this study, Vietnamese construction contractors will be able to come up with workable solutions which will contribute towards a better performance of construction workers. On that basis, the productivity of construction firms and national economy will be improved correspondingly. Keywords: productivity; labour productivity; factors affecting; construction worker.
{"title":"Factors affecting labour productivity of construction worker on construction site: A case of Hanoi","authors":"N. Tâm, Nguyen Thi Lien Huong, Nguyen Bao Ngoc","doi":"10.31814/STCE.NUCE2018-12(5)-13","DOIUrl":"https://doi.org/10.31814/STCE.NUCE2018-12(5)-13","url":null,"abstract":"Labour productivity of Vietnamese economy in general and of Vietnamese construction industry in particular is low in comparison with other countries. Boosting labour productivity is becoming an urgency and is attracting much attention from both domestic and foreign researchers. This paper focuses on a series of factors affecting labour productivity on construction site in Hanoi. The research aims to evaluate and rate the extent of impact of each factor to labour productivity. By referring to the outcomes of this study, Vietnamese construction contractors will be able to come up with workable solutions which will contribute towards a better performance of construction workers. On that basis, the productivity of construction firms and national economy will be improved correspondingly. \u0000Keywords: productivity; labour productivity; factors affecting; construction worker. ","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78850599","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 : 2018-08-30DOI: 10.31814/STCE.NUCE2018-12(5)-04
N. Hieu, V. Tuan
In this study, the differential evolution algorithm is used for solving the optimum design problem of composite cellular beams. The design variables are hot rolled profile from which the cellular beam will be produced as well as opening size and its spacing. The objective function is the minimum weight of cellular beam while the design constraints include satisfying the ultimate limit states, the serviceability limit states and the geometric limitations. The design method adopted in this study is based on EN 1994-1-1. Furthermore, a parametric study is conducted to evaluate the influence of beams spacing to the weight of floor beam system. As a result, an optimal spacing of composite cellular beams is proposed. Keywords: composite beam; cellular beam; web opening; steel beam optimization; differential evolution.
{"title":"Weight optimization of composite cellular beam based on the differential evolution algorithm","authors":"N. Hieu, V. Tuan","doi":"10.31814/STCE.NUCE2018-12(5)-04","DOIUrl":"https://doi.org/10.31814/STCE.NUCE2018-12(5)-04","url":null,"abstract":"In this study, the differential evolution algorithm is used for solving the optimum design problem of composite cellular beams. The design variables are hot rolled profile from which the cellular beam will be produced as well as opening size and its spacing. The objective function is the minimum weight of cellular beam while the design constraints include satisfying the ultimate limit states, the serviceability limit states and the geometric limitations. The design method adopted in this study is based on EN 1994-1-1. Furthermore, a parametric study is conducted to evaluate the influence of beams spacing to the weight of floor beam system. As a result, an optimal spacing of composite cellular beams is proposed. \u0000Keywords: composite beam; cellular beam; web opening; steel beam optimization; differential evolution.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87667799","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 : 2018-08-30DOI: 10.31814/stce.nuce2018-12(5)-07
P. Dong
Vacuum consolidation preloading method (VCM) has been widely adopted as an effective solution for soft soil improvement over the world. Recently, VCM has been successfully applied for improving the geotechnical properties of dredged mud, which is normally dumped at reclamation area by hydraulic pumping. However, it has been also reported that application of VCM for treatment of the dredged mud has been failed in some particular cases. The failures are mainly caused by clogging problem in vertical drains due to fine-grained soils that reduces the drainage efficiency of drainage system. To address this issue, a series of model tests have been conducted to investigate the performances of vertical drains among prefabricated vertical drain, sand drain and filter pipe. As the goal, the performances of types of the vertical drain solutions are analyzed based on the monitoring data of settlement, influencing zone surrounding the vertical drains. The test results reveal that sand drain shows the best performance among the others. In addition, the clogging problem is clearly shown in case of PVD. Keywords: dredging slurry; vacuum consolidation method; model test; PVD; filter pipe; sand drain.
{"title":"Influence of vertical drains on improving dredged mud by vacuum consolidation method","authors":"P. Dong","doi":"10.31814/stce.nuce2018-12(5)-07","DOIUrl":"https://doi.org/10.31814/stce.nuce2018-12(5)-07","url":null,"abstract":"Vacuum consolidation preloading method (VCM) has been widely adopted as an effective solution for soft soil improvement over the world. Recently, VCM has been successfully applied for improving the geotechnical properties of dredged mud, which is normally dumped at reclamation area by hydraulic pumping. However, it has been also reported that application of VCM for treatment of the dredged mud has been failed in some particular cases. The failures are mainly caused by clogging problem in vertical drains due to fine-grained soils that reduces the drainage efficiency of drainage system. To address this issue, a series of model tests have been conducted to investigate the performances of vertical drains among prefabricated vertical drain, sand drain and filter pipe. As the goal, the performances of types of the vertical drain solutions are analyzed based on the monitoring data of settlement, influencing zone surrounding the vertical drains. The test results reveal that sand drain shows the best performance among the others. In addition, the clogging problem is clearly shown in case of PVD. \u0000Keywords: dredging slurry; vacuum consolidation method; model test; PVD; filter pipe; sand drain.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91093258","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 : 2018-08-30DOI: 10.31814/STCE.NUCE2018-12(5)-09
Tran Minh Tung
Urban renewal projects are becoming more and more active, especially in public-owned gold land plots in Vietnam's cities center. The re-development of these land resources known as the residentialization: transformation of different land-use functions into new residential areas (also new neighborhoods) - the KDTM ({Khu Do Thi Moi} abbreviated in Vietnamese) - is increasing the urban density in these areas. Vietnam uses three factors to control urban density: building density; number of floors and/or height of the building; floor area ratio. The current tasks of land-use policies are the determination of an urban density that can adapt to the development of urban space; take full advantage of the land value increment, boost investments without causing any consequences because of the overcrowded population. The residential units will be called compact units when their (occupancy) density exceeds the threshold of 300 persons/ha. For the Compact-KDT concept (compacted KDTM), it is recommended to have: (1) the average level of compactness corresponding to the density of 300 to 600 persons/ha; (2a) the high level of compactness to be controlled - 600 to 1200 persons/ha; (2b) the high level of compactness to be strictly controlled and applied in some exceptional cases - 1200 to 2000 persons/ha; (3) the extremely high level of compactness to be avoided - more than 2000 persons/ha. A Compact-KDT always guarantees the functions of a "normal" KDTM, there are some functionalities that should be added: organization of land-use and spatial functions; public spaces; internal traffic; and reducing energy consumption and the use of non-recyclable natural resources. Rather than being passive to fluctuations in urban density, this increase can be accommodated with a calm and fair attitude by analyzing adverse consequences and the benefits of this process, not just negative effects for the development of urban space, the concentration of population and the economic growth of cities. Keywords: urban renewal; urban density; new urban areas/new residential areas (KDTM - Khu Do Thi Moi); residentialization; (new) compact urban areas (Compacted KDTM/Compact-KDT).
{"title":"Urban renewal applicable to an increase in density: Conceptualization of compact-KDT in Vietnam with Hanoi as a case study","authors":"Tran Minh Tung","doi":"10.31814/STCE.NUCE2018-12(5)-09","DOIUrl":"https://doi.org/10.31814/STCE.NUCE2018-12(5)-09","url":null,"abstract":"Urban renewal projects are becoming more and more active, especially in public-owned gold land plots in Vietnam's cities center. The re-development of these land resources known as the residentialization: transformation of different land-use functions into new residential areas (also new neighborhoods) - the KDTM ({Khu Do Thi Moi} abbreviated in Vietnamese) - is increasing the urban density in these areas. Vietnam uses three factors to control urban density: building density; number of floors and/or height of the building; floor area ratio. The current tasks of land-use policies are the determination of an urban density that can adapt to the development of urban space; take full advantage of the land value increment, boost investments without causing any consequences because of the overcrowded population. The residential units will be called compact units when their (occupancy) density exceeds the threshold of 300 persons/ha. For the Compact-KDT concept (compacted KDTM), it is recommended to have: (1) the average level of compactness corresponding to the density of 300 to 600 persons/ha; (2a) the high level of compactness to be controlled - 600 to 1200 persons/ha; (2b) the high level of compactness to be strictly controlled and applied in some exceptional cases - 1200 to 2000 persons/ha; (3) the extremely high level of compactness to be avoided - more than 2000 persons/ha. A Compact-KDT always guarantees the functions of a \"normal\" KDTM, there are some functionalities that should be added: organization of land-use and spatial functions; public spaces; internal traffic; and reducing energy consumption and the use of non-recyclable natural resources. Rather than being passive to fluctuations in urban density, this increase can be accommodated with a calm and fair attitude by analyzing adverse consequences and the benefits of this process, not just negative effects for the development of urban space, the concentration of population and the economic growth of cities. \u0000Keywords: urban renewal; urban density; new urban areas/new residential areas (KDTM - Khu Do Thi Moi); residentialization; (new) compact urban areas (Compacted KDTM/Compact-KDT).","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75280322","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 : 2018-08-30DOI: 10.31814/STCE.NUCE2018-12(5)-05
Nguyen Hung Cuong, Luu Van Thuc, Tran Hong Hai, Pham Nguyen Van Phuong
This paper presents the experimental results of researching on plastic shrinkage (plastic deformation) and the effect of curing methods on the process of plastic shrinkage at the early stages when self-compacting concrete (SCC) starts setting and develops the strength. The experiments were carried out in two typical climatic conditions in Vietnam which are humid and dry. The experiments were conducted with two typical water/powder ratios of 0.3 and 0.35 and four cases of curing methods which are nylon membrane, watering, no-curing and soaking in water (the standard condition). Besides, the influences of plastic shrinkage at the early stages on strength development and occurrence of surface cracking of SCC were also investigated. The conclusions were drawn about the plastic deformation process and the curing method that might minimize plastic shrinkage of SCC, control surface cracking early, and ensure the quality and strength of SCC in the hot and humid climatic condition of Vietnam. Keywords: plastic shrinkage; self-compacting concrete; hot and humid climate; hardening process.
{"title":"Effects of the curing methods on the process of plastic shrinkage of self-compacting concrete in Vietnam","authors":"Nguyen Hung Cuong, Luu Van Thuc, Tran Hong Hai, Pham Nguyen Van Phuong","doi":"10.31814/STCE.NUCE2018-12(5)-05","DOIUrl":"https://doi.org/10.31814/STCE.NUCE2018-12(5)-05","url":null,"abstract":"This paper presents the experimental results of researching on plastic shrinkage (plastic deformation) and the effect of curing methods on the process of plastic shrinkage at the early stages when self-compacting concrete (SCC) starts setting and develops the strength. The experiments were carried out in two typical climatic conditions in Vietnam which are humid and dry. The experiments were conducted with two typical water/powder ratios of 0.3 and 0.35 and four cases of curing methods which are nylon membrane, watering, no-curing and soaking in water (the standard condition). Besides, the influences of plastic shrinkage at the early stages on strength development and occurrence of surface cracking of SCC were also investigated. The conclusions were drawn about the plastic deformation process and the curing method that might minimize plastic shrinkage of SCC, control surface cracking early, and ensure the quality and strength of SCC in the hot and humid climatic condition of Vietnam. \u0000Keywords: plastic shrinkage; self-compacting concrete; hot and humid climate; hardening process.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78672327","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 : 2018-08-30DOI: 10.31814/STCE.NUCE2018-12(5)-03
Van Viet Thien An
In the present study, the uniformity and potential internal defects of concrete elements in situ were assessed by using Ultrasonic Pulse Velocity (UPV) testing method according to TCVN 9357:2012. Thirteen cross beams with dimension of 4.8 x 1.5 x 1.5 m3 were selected to measure the pulse velocity. Three cross beams were used to check potential internal defects in concrete and 10 cross beams were used to assess the uniformity of concrete in the elements. The results showed that there is no potential internal defect with size over 100 mm in three tested beams and concrete quality of all tested beams is good with the coefficient of variation (CV) of ultrasonic pulse velocity results of all tested points is lower than 2%. Keywords: concrete; homogeneity; internal defects; ultrasonic pulse velocity.
本研究根据TCVN 9357:2012，采用超声脉冲速度(UPV)测试方法对混凝土构件的均匀性和潜在内部缺陷进行原位评估。选择尺寸为4.8 x 1.5 x 1.5 m3的13根横梁来测量脉冲速度。3根横梁用于检查混凝土潜在的内部缺陷，10根横梁用于评估混凝土在构件中的均匀性。结果表明:3根试验梁均未发现尺寸大于100 mm的潜在内部缺陷，各试验梁的混凝土质量均较好，各测点超声脉冲速度的变异系数(CV)均小于2%。关键词:混凝土;同质性;内部缺陷;超声波脉冲速度。
{"title":"The assessment of concrete quality by ultrasonic pulse velocity","authors":"Van Viet Thien An","doi":"10.31814/STCE.NUCE2018-12(5)-03","DOIUrl":"https://doi.org/10.31814/STCE.NUCE2018-12(5)-03","url":null,"abstract":"In the present study, the uniformity and potential internal defects of concrete elements in situ were assessed by using Ultrasonic Pulse Velocity (UPV) testing method according to TCVN 9357:2012. Thirteen cross beams with dimension of 4.8 x 1.5 x 1.5 m3 were selected to measure the pulse velocity. Three cross beams were used to check potential internal defects in concrete and 10 cross beams were used to assess the uniformity of concrete in the elements. The results showed that there is no potential internal defect with size over 100 mm in three tested beams and concrete quality of all tested beams is good with the coefficient of variation (CV) of ultrasonic pulse velocity results of all tested points is lower than 2%. \u0000Keywords: concrete; homogeneity; internal defects; ultrasonic pulse velocity.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85601850","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 : 2018-08-30DOI: 10.31814/STCE.NUCE2018-12(5)-12
B. Hieu
Satellite based precipitation product (GSMaP-MVK) can be reliably used to estimate the Areal Mean Precipitation error based on “Sample Design method” (Esdd) with the effort to mitigate the problem of sparse data, especially severe in poorly gauged river basins. In addition, the satellite-gauge merging precipitation would reduce significantly the magnitude gaps between the satellite rainfall estimations and the rain gauge data. In this study, the capability of satellite-gauge merging precipitation using GSMaP-MVK and local dense rain gauge data with bias reduction approach to evaluate the AMP is investigated. The main finding is that satellite-gauge blending data which incorporates a dense rain gauge measurements shows the better capability to evaluate AMP using Esdd index than the original satellite only precipitation estimations. However, Esdd quantification performances of satellite-gauge blending precipitation are inferior to the original satellite only precipitation product GSMaP-MVK when the number of blended rain gauges is not large enough. Keywords: areal mean precipitation; remote sensed precipitation product; satellite-gauge merging; rainfall runoff simulations.
{"title":"Study on quantification of areal mean precipitation using satellite-gauge merging precipitation","authors":"B. Hieu","doi":"10.31814/STCE.NUCE2018-12(5)-12","DOIUrl":"https://doi.org/10.31814/STCE.NUCE2018-12(5)-12","url":null,"abstract":"Satellite based precipitation product (GSMaP-MVK) can be reliably used to estimate the Areal Mean Precipitation error based on “Sample Design method” (Esdd) with the effort to mitigate the problem of sparse data, especially severe in poorly gauged river basins. In addition, the satellite-gauge merging precipitation would reduce significantly the magnitude gaps between the satellite rainfall estimations and the rain gauge data. In this study, the capability of satellite-gauge merging precipitation using GSMaP-MVK and local dense rain gauge data with bias reduction approach to evaluate the AMP is investigated. The main finding is that satellite-gauge blending data which incorporates a dense rain gauge measurements shows the better capability to evaluate AMP using Esdd index than the original satellite only precipitation estimations. However, Esdd quantification performances of satellite-gauge blending precipitation are inferior to the original satellite only precipitation product GSMaP-MVK when the number of blended rain gauges is not large enough. \u0000Keywords: areal mean precipitation; remote sensed precipitation product; satellite-gauge merging; rainfall runoff simulations.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72784464","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：