Pub Date : 2019-01-31DOI: 10.31814/stce.nuce2019-13(1)-08
Aaron Vansintjan, Nguyen Van, Le Quynh Chi, Nguyen Thanh Tu
Since Vietnam shifted to a market-economy in the 1980s, Hanoi has seen rapid urban expansion similar to that of other South East Asian cities - involving megaprojects, luxury developments, rural-to-urban migration, informal housing construction, and escalating speculation. Researchers have considered how unemployment and the disruption of community life followed the urbanization of rural areas. However, little has been said about how people adjusted their everyday life to cope with the changes. Through in-depth interviews, focus groups, participatory observation, oral histories, and surveys, this research investigated the adaptation strategies of low-income residents in the face of land use changes that are beyond their control. The main research site is Tay Ho district - previously a conglomeration of agricultural villages that has, in the past 20 years, witnessed rapid transformation through large-scale infrastructures, luxury housing, and smaller lodgings built individually for migrant workers. Four main adaptation strategies used by residents have been identified. First, people turn to food as a safety net. Running small street stalls, selling goods in local markets, and delivering to restaurants are common. Second, as farms transform into roads and buildings, people take advantage of public space to garden and socialize with neighbours. Third, gender division is significant as women are often excluded from the male-dominated land inheritance system and the formal economy, so they turn to informal trade, which offers autonomy and helps to develop social connections. Fourth, as land is confiscated and compensated by a lump sum of cash, people build social capital to persevere. This paper suggests that, in the context of rising globalization, the urbanization of the countryside, and the need to ensure the sustainability and inclusivity of cities, urban planners and policy-makers should take into account the way by which low-income residents continue to rely on environmental and social capital to adapt to changes. Keywords: urbanization; informality; adaptation; resilience; environmental capital; social capital; privatization. Received 18 July 2018, Revised 09 September 2018, Accepted 18 December 2018
{"title":"Adaptation strategies used by low-income residents affected by land use changes in Hanoi, Vietnam","authors":"Aaron Vansintjan, Nguyen Van, Le Quynh Chi, Nguyen Thanh Tu","doi":"10.31814/stce.nuce2019-13(1)-08","DOIUrl":"https://doi.org/10.31814/stce.nuce2019-13(1)-08","url":null,"abstract":"Since Vietnam shifted to a market-economy in the 1980s, Hanoi has seen rapid urban expansion similar to that of other South East Asian cities - involving megaprojects, luxury developments, rural-to-urban migration, informal housing construction, and escalating speculation. Researchers have considered how unemployment and the disruption of community life followed the urbanization of rural areas. However, little has been said about how people adjusted their everyday life to cope with the changes. Through in-depth interviews, focus groups, participatory observation, oral histories, and surveys, this research investigated the adaptation strategies of low-income residents in the face of land use changes that are beyond their control. The main research site is Tay Ho district - previously a conglomeration of agricultural villages that has, in the past 20 years, witnessed rapid transformation through large-scale infrastructures, luxury housing, and smaller lodgings built individually for migrant workers. Four main adaptation strategies used by residents have been identified. First, people turn to food as a safety net. Running small street stalls, selling goods in local markets, and delivering to restaurants are common. Second, as farms transform into roads and buildings, people take advantage of public space to garden and socialize with neighbours. Third, gender division is significant as women are often excluded from the male-dominated land inheritance system and the formal economy, so they turn to informal trade, which offers autonomy and helps to develop social connections. Fourth, as land is confiscated and compensated by a lump sum of cash, people build social capital to persevere. This paper suggests that, in the context of rising globalization, the urbanization of the countryside, and the need to ensure the sustainability and inclusivity of cities, urban planners and policy-makers should take into account the way by which low-income residents continue to rely on environmental and social capital to adapt to changes. \u0000Keywords: urbanization; informality; adaptation; resilience; environmental capital; social capital; privatization. \u0000Received 18 July 2018, Revised 09 September 2018, Accepted 18 December 2018","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88177646","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 : 2019-01-31DOI: 10.31814/stce.nuce2019-13(1)-11
Nguyen Manh Tuan
The concepts of Building Information Modeling (BIM) and Lean construction are increasingly popular and used for the purpose of improving the efficiency of construction projects. The Lean construction approach helps optimize the system, thereby minimizing the waste and increase the maximum amount of value for clients. This is in line with the effectiveness of BIM for the purpose of analyzing, evaluating, and managing projects based on the virtual information model before, during and after construction. The combination of BIM and Lean construction will certainly be the trend of the construction industry in the near future. This paper aims to analyze the integration of Lean construction principles in the BIM coordination process through a specific case study. The project management unit is responsible for managing and evaluating BIM models from consultants and contractors and serves as the project's BIM coordinator. Keywords: building information modeling; BIM coordination process; Lean construction; Lean principles. Received 20 November 2018, Revised 30 December 2018, Accepted 25 January 2019
{"title":"An analysis of the integration of Lean construction principles in the BIM coordination process","authors":"Nguyen Manh Tuan","doi":"10.31814/stce.nuce2019-13(1)-11","DOIUrl":"https://doi.org/10.31814/stce.nuce2019-13(1)-11","url":null,"abstract":"The concepts of Building Information Modeling (BIM) and Lean construction are increasingly popular and used for the purpose of improving the efficiency of construction projects. The Lean construction approach helps optimize the system, thereby minimizing the waste and increase the maximum amount of value for clients. This is in line with the effectiveness of BIM for the purpose of analyzing, evaluating, and managing projects based on the virtual information model before, during and after construction. The combination of BIM and Lean construction will certainly be the trend of the construction industry in the near future. This paper aims to analyze the integration of Lean construction principles in the BIM coordination process through a specific case study. The project management unit is responsible for managing and evaluating BIM models from consultants and contractors and serves as the project's BIM coordinator. \u0000Keywords: building information modeling; BIM coordination process; Lean construction; Lean principles. \u0000Received 20 November 2018, Revised 30 December 2018, Accepted 25 January 2019","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88619211","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 : 2019-01-31DOI: 10.31814/stce.nuce2019-13(1)-10
P. Thao
Rice straw open burning is the most common form of agricultural by-product treatment in developing countries. Contaminated pollutants pollute the environment, badly affect human's health and contribute to the increase of greenhouse gases that impact climate change. This research was carried out to estimate the amount of rice straw produced, a seasonal burning rate and the modified combustion efficiency (MCE) from field-based rice straw open burning by field sampling method, field survey and quick measurement; the inventory is based on emission factors. The results show that 62% of respondents use rice straw for different purposes such as cattle feed, selling, composting... 38% respondents do not use for any purposes. The main disposal method is open burning. Open burning rate is different in each cultivative season. It was 36.36%, in winter-spring crop, 49.32% in summer-autumn crop and 40% in winter-autumn crop. In 2017, total CO2 emissions from open burning were the highest compared with two other pollutants. It was nearly 5.7 million tons and followed by CO with 135.1 thousand tons. The other pollutants emitted from open burning were PM2.5 (50.4 thousand tons), PM10 (14.4 thousand tons), SO2 (7.78 thousand tons), NO2 (0.27 thousand tons) per year. The inventory results show that rice straw open burning in An Giang has been affecting on the quality of the air environment, landscape and reducing the traffic vision; especially fine dust (PM2.5) greatly affects to local people’s health. If all surplus rice straw is used for energy production, it can help not only reduce fossil fuel use, but also reduce the amount of pollutants generated by open burning. This is a win-win solution that should be paid attention by the local authorities to come up with appropriate incentives. Keywords: emission inventory; rice straw; open burning; emissions. Received 20 December 2018, Revised 25 January 2019, Accepted 28 January 2019
{"title":"Research on emissions inventory for rice straw open burning in An Giang province","authors":"P. Thao","doi":"10.31814/stce.nuce2019-13(1)-10","DOIUrl":"https://doi.org/10.31814/stce.nuce2019-13(1)-10","url":null,"abstract":"Rice straw open burning is the most common form of agricultural by-product treatment in developing countries. Contaminated pollutants pollute the environment, badly affect human's health and contribute to the increase of greenhouse gases that impact climate change. This research was carried out to estimate the amount of rice straw produced, a seasonal burning rate and the modified combustion efficiency (MCE) from field-based rice straw open burning by field sampling method, field survey and quick measurement; the inventory is based on emission factors. The results show that 62% of respondents use rice straw for different purposes such as cattle feed, selling, composting... 38% respondents do not use for any purposes. The main disposal method is open burning. Open burning rate is different in each cultivative season. It was 36.36%, in winter-spring crop, 49.32% in summer-autumn crop and 40% in winter-autumn crop. In 2017, total CO2 emissions from open burning were the highest compared with two other pollutants. It was nearly 5.7 million tons and followed by CO with 135.1 thousand tons. The other pollutants emitted from open burning were PM2.5 (50.4 thousand tons), PM10 (14.4 thousand tons), SO2 (7.78 thousand tons), NO2 (0.27 thousand tons) per year. The inventory results show that rice straw open burning in An Giang has been affecting on the quality of the air environment, landscape and reducing the traffic vision; especially fine dust (PM2.5) greatly affects to local people’s health. If all surplus rice straw is used for energy production, it can help not only reduce fossil fuel use, but also reduce the amount of pollutants generated by open burning. This is a win-win solution that should be paid attention by the local authorities to come up with appropriate incentives. \u0000Keywords: emission inventory; rice straw; open burning; emissions. \u0000Received 20 December 2018, Revised 25 January 2019, Accepted 28 January 2019","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81784665","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 : 2019-01-31DOI: 10.31814/STCE.NUCE2019-13(1)-07
D. H. Anh, N. Anh
In coastal areas and islands, farmlands often lack of nutrients. This research assessed the precipitation of phosphorus presenting in urine in the form of struvite of magnesium ammonium phosphate (MAP) by adding of supplement of Mg2+ ion from MgCl2 solution contained in seawater (Cat Ba island area). The urine and seawater have been mixed at different ratios. The results have shown [Mg]:[PO4] ratios ranging from 0.75 to 5.26 allowed the precipitation of more than 90% of the phosphorus in the urine. Seawater – to – urine ratios of 0.67/1, 1.3/1, 3.2/1, 5/1, 7/1 and 9/1 in volume would give phosphorus recovery efficiency of 99%, 92%, 96%, 96%, 95% and 99%, respectively. Seawater in the studied area could be an appropriate Mg2+ ion source to produce MAP from urine diverting dry toilets. Recovered phosphorus can be used as slow releasing fertilize for farming. Keywords: MAP: phosphorus recovery; seawater; urine; struvite. Received 24 October 2018, Revised 23 December 2018, Accepted 29 January 2019
{"title":"Phosphorus recovery from urine by adding difference sources of magnesium ion, applying for rural, coastal and island areas in Vietnam","authors":"D. H. Anh, N. Anh","doi":"10.31814/STCE.NUCE2019-13(1)-07","DOIUrl":"https://doi.org/10.31814/STCE.NUCE2019-13(1)-07","url":null,"abstract":"In coastal areas and islands, farmlands often lack of nutrients. This research assessed the precipitation of phosphorus presenting in urine in the form of struvite of magnesium ammonium phosphate (MAP) by adding of supplement of Mg2+ ion from MgCl2 solution contained in seawater (Cat Ba island area). The urine and seawater have been mixed at different ratios. The results have shown [Mg]:[PO4] ratios ranging from 0.75 to 5.26 allowed the precipitation of more than 90% of the phosphorus in the urine. Seawater – to – urine ratios of 0.67/1, 1.3/1, 3.2/1, 5/1, 7/1 and 9/1 in volume would give phosphorus recovery efficiency of 99%, 92%, 96%, 96%, 95% and 99%, respectively. Seawater in the studied area could be an appropriate Mg2+ ion source to produce MAP from urine diverting dry toilets. Recovered phosphorus can be used as slow releasing fertilize for farming. \u0000Keywords: MAP: phosphorus recovery; seawater; urine; struvite. \u0000Received 24 October 2018, Revised 23 December 2018, Accepted 29 January 2019","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76351552","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 : 2019-01-31DOI: 10.31814/STCE.NUCE2019-13(1)-05
N. Vuong, M. H. Quan
In the past few decades and up to now, the fossil energy has exerted tremendous impacts on human environments and gives rise to greenhouse effects while the wind power, especially in offshore region, is an attractive renewable energy resource. For offshore fixed wind turbine, stronger foundation like jacket structure has a good applicability for deeper water depth. Once water depth increases, dynamic responses of offshore wind turbine (OWT) support structures become an important issue. The primary factor will be the total height of support structure increases when wind turbine is installed at offshore locations with deeper water depth, in other words the fatigue life of each components of support structure decrease. The other one will experience more wind forces due to its large blades, apart from wave, current forces, when makes a comparison with offshore oil and gas platforms. Summing up two above reasons, fatigue analysis, in this research, is a crucial aspect for design of offshore wind turbine structures which are subjected to time series wind, wave loads and carried out by aiding of SACS software for model simulation (P-M rules and S-N curves) and Matlab code. Results show that the fatigue life of OWT is decreased accordingly by increasing the wind speed acting on the blades, especially with the simultaneous interaction between wind and wind-induced wave. Hence, this should be considered in wind turbine design. Keywords: offshore wind turbine; Jacket structure; fatigue analysis; P-M rules; S-N curves. Received 01 October 2018, Revised 19 November 2018, Accepted 31 January 2019
{"title":"Fatigue analysis of jacket support structure for offshore wind turbines","authors":"N. Vuong, M. H. Quan","doi":"10.31814/STCE.NUCE2019-13(1)-05","DOIUrl":"https://doi.org/10.31814/STCE.NUCE2019-13(1)-05","url":null,"abstract":"In the past few decades and up to now, the fossil energy has exerted tremendous impacts on human environments and gives rise to greenhouse effects while the wind power, especially in offshore region, is an attractive renewable energy resource. For offshore fixed wind turbine, stronger foundation like jacket structure has a good applicability for deeper water depth. Once water depth increases, dynamic responses of offshore wind turbine (OWT) support structures become an important issue. The primary factor will be the total height of support structure increases when wind turbine is installed at offshore locations with deeper water depth, in other words the fatigue life of each components of support structure decrease. The other one will experience more wind forces due to its large blades, apart from wave, current forces, when makes a comparison with offshore oil and gas platforms. Summing up two above reasons, fatigue analysis, in this research, is a crucial aspect for design of offshore wind turbine structures which are subjected to time series wind, wave loads and carried out by aiding of SACS software for model simulation (P-M rules and S-N curves) and Matlab code. Results show that the fatigue life of OWT is decreased accordingly by increasing the wind speed acting on the blades, especially with the simultaneous interaction between wind and wind-induced wave. Hence, this should be considered in wind turbine design. \u0000Keywords: offshore wind turbine; Jacket structure; fatigue analysis; P-M rules; S-N curves. \u0000Received 01 October 2018, Revised 19 November 2018, Accepted 31 January 2019","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85203699","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 : 2019-01-31DOI: 10.31814/stce.nuce2019-13(1)-09
Tran Minh Tung
Due to the policy of the Doi moi in Vietnam started in 1986, Hanoi has undergone many important changes. Currently, Hanoi's traffic is characterized by seemingly continuous motorcycle flows - a representative of high personal mobility in the context of rising incomes. Congestion, dust, pollution, insecurity, overload, etc., they are important keywords to describe Hanoi's urban traffic. Hanoi has put in place a number of policies to improve the transportation system. In 2017, in Hanoi's new mobility improvement project, there is a regulation on motorcycles: “The municipality will zone by limiting the activities of motorcycles according to the infrastructure and the service capacity of the public transportation system to stop motorcycle activities in the central districts in 2030” that becomes controversial. This article, based on the results of surveys assessing the level of satisfaction and desires of people about traffic at the KDTMs of Hanoi, analyzes the differences between the wishes of the municipality and the practices of Hanoi, through habits, modes of mobility of KDTM residents - the new residential areas of Hanoi that bring a different atmosphere of habitat compared to existing neighborhoods, by changing the mode of (re)making of the city. How will the traffic of KDTM residents be affected by this decision as well as how KDTMs will participate in the sustainable transportation of Hanoi?. It is the KDTMs with their “novelties” that will have to become pioneers creating opportunities of the changing of Hanoi traffic. Keywords: Hanoi; sustainable mobility; efficient transportation; motorcycle; KDTM (new residential area). Received 08 December 2018, Revised 30 January 2019, Accepted 30 January 2019
{"title":"Sustainabilization of Hanoi mobility approached from new residential areas: Will it be a city without motorbike?","authors":"Tran Minh Tung","doi":"10.31814/stce.nuce2019-13(1)-09","DOIUrl":"https://doi.org/10.31814/stce.nuce2019-13(1)-09","url":null,"abstract":"Due to the policy of the Doi moi in Vietnam started in 1986, Hanoi has undergone many important changes. Currently, Hanoi's traffic is characterized by seemingly continuous motorcycle flows - a representative of high personal mobility in the context of rising incomes. Congestion, dust, pollution, insecurity, overload, etc., they are important keywords to describe Hanoi's urban traffic. Hanoi has put in place a number of policies to improve the transportation system. In 2017, in Hanoi's new mobility improvement project, there is a regulation on motorcycles: “The municipality will zone by limiting the activities of motorcycles according to the infrastructure and the service capacity of the public transportation system to stop motorcycle activities in the central districts in 2030” that becomes controversial. This article, based on the results of surveys assessing the level of satisfaction and desires of people about traffic at the KDTMs of Hanoi, analyzes the differences between the wishes of the municipality and the practices of Hanoi, through habits, modes of mobility of KDTM residents - the new residential areas of Hanoi that bring a different atmosphere of habitat compared to existing neighborhoods, by changing the mode of (re)making of the city. How will the traffic of KDTM residents be affected by this decision as well as how KDTMs will participate in the sustainable transportation of Hanoi?. It is the KDTMs with their “novelties” that will have to become pioneers creating opportunities of the changing of Hanoi traffic. \u0000Keywords: Hanoi; sustainable mobility; efficient transportation; motorcycle; KDTM (new residential area). \u0000Received 08 December 2018, Revised 30 January 2019, Accepted 30 January 2019","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78389036","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 : 2019-01-31DOI: 10.31814/STCE.NUCE2019-13(1)-02
Pham Thai Hoan, N. Thuong
This study investigated the synergy in shear response of ultra-high-performance fiber-reinforced concrete (UHPFRCs) containing different contents of long and short smooth steel fiber reinforcements at high strain rates. Shear resistance of two ultra-high-performance mono-fiber-reinforced concrete (UHP-MFRCs): L15S00 (containing 1.5 vol.-% long and 0.0 vol.-% short fiber) or L00S15, and one ultra-high-performance hybrid-fiber-reinforced concrete (UHP-HFRCs): L10S05 (containing 1.0 vol.-% long and 0.5 vol.-% short fiber) at high strain rates of up to 272 s-1 was investigated using a new shear test setup by an improved strain energy frame impact machine (I-SEFIM). The L10S05 generated high synergy in shear strength, shear peak toughness at static rate and high synergy in shear strain, shear peak toughness at high strain rates. Moreover, all the investigated UHPFRCs were sensitive to the applied strain rates, especially in term of shear strength. Keywords: UHPFRCs; shear resistance; synergy effect; strain-rate dependent; impact. Received 23 August 2018, Revised 29 September 2018, Accepted 18 December 2018
{"title":"Shear resistance of ultra-high-performance concrete reinforced with hybrid steel fiber subjected to impact loading","authors":"Pham Thai Hoan, N. Thuong","doi":"10.31814/STCE.NUCE2019-13(1)-02","DOIUrl":"https://doi.org/10.31814/STCE.NUCE2019-13(1)-02","url":null,"abstract":"This study investigated the synergy in shear response of ultra-high-performance fiber-reinforced concrete (UHPFRCs) containing different contents of long and short smooth steel fiber reinforcements at high strain rates. Shear resistance of two ultra-high-performance mono-fiber-reinforced concrete (UHP-MFRCs): L15S00 (containing 1.5 vol.-% long and 0.0 vol.-% short fiber) or L00S15, and one ultra-high-performance hybrid-fiber-reinforced concrete (UHP-HFRCs): L10S05 (containing 1.0 vol.-% long and 0.5 vol.-% short fiber) at high strain rates of up to 272 s-1 was investigated using a new shear test setup by an improved strain energy frame impact machine (I-SEFIM). The L10S05 generated high synergy in shear strength, shear peak toughness at static rate and high synergy in shear strain, shear peak toughness at high strain rates. Moreover, all the investigated UHPFRCs were sensitive to the applied strain rates, especially in term of shear strength. \u0000Keywords: UHPFRCs; shear resistance; synergy effect; strain-rate dependent; impact. \u0000Received 23 August 2018, Revised 29 September 2018, Accepted 18 December 2018","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82199882","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 : 2019-01-31DOI: 10.31814/STCE.NUCE2019-13(1)-06
L. H. Chuong, Ung Quoc Trang, Ngoc-Tra-My Lam
With the purpose of obtaining the shear strength parameters (friction angle, φ, and cohesion, c) of asphalt concretes. At the present time, almost the testing devices were designed based on the condition of the vehicle's load when they are moving on the pavement structure. That means, the fatigue resistance of the interfaces was determined through the loads acting at the interfaces between layers are repetitive mechanical action of the moving vehicles. With that view, the ratio of the normal and shear fatigue loads of asphalt concrete was not considered in terms of the nature of the material. An asphalt concrete testing device is proposed based on the modification from AST-2 instrument and Shear Fatigue Test instrument. The main parameters of this device are calculated from the ratio of shear stress and normal stress at the fatigue of the asphalt concrete according to the Mohr-Coulomb failure criterion. Test results with asphalt specimens show that the device is stable, the acting vertical loads were smaller and more stable. Keywords: normal strength; shear stress; asphalt concrete; fatigue stresses. Received 4 December 2018, Revised 20 December 2018, Accepted 24 January 2019
{"title":"Asphalt concrete testing device: Studying and designing based on the properties of asphalt concrete","authors":"L. H. Chuong, Ung Quoc Trang, Ngoc-Tra-My Lam","doi":"10.31814/STCE.NUCE2019-13(1)-06","DOIUrl":"https://doi.org/10.31814/STCE.NUCE2019-13(1)-06","url":null,"abstract":"With the purpose of obtaining the shear strength parameters (friction angle, φ, and cohesion, c) of asphalt concretes. At the present time, almost the testing devices were designed based on the condition of the vehicle's load when they are moving on the pavement structure. That means, the fatigue resistance of the interfaces was determined through the loads acting at the interfaces between layers are repetitive mechanical action of the moving vehicles. With that view, the ratio of the normal and shear fatigue loads of asphalt concrete was not considered in terms of the nature of the material. An asphalt concrete testing device is proposed based on the modification from AST-2 instrument and Shear Fatigue Test instrument. The main parameters of this device are calculated from the ratio of shear stress and normal stress at the fatigue of the asphalt concrete according to the Mohr-Coulomb failure criterion. Test results with asphalt specimens show that the device is stable, the acting vertical loads were smaller and more stable. \u0000Keywords: normal strength; shear stress; asphalt concrete; fatigue stresses. \u0000Received 4 December 2018, Revised 20 December 2018, Accepted 24 January 2019","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85257308","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 : 2018-09-28DOI: 10.31814/stce.nuce2018-12(6)-08
Vũ Văn Thặng
Hiện nay bản đồ giấy dần được thay thế bởi bản đồ số trong trong quy hoạch thiết kế các khu đô thị, khu công nghiệp và nhiều công tác khác. Bản đồ giấy truyền thống và bản đồ số đều có đặc trưng kỹ thuật cơ bản đó là tỉ lệ của bản đồ. Bài báo khảo sát, phân tích hai đặc trưng cơ bản là độ chính xác và mức độ khái quát hóa địa hình, địa vật phụ thuộc theo tỉ lệ của bản đồ. Khảo sát, phân tích sai số xác định điểm, đoạn thẳng, diện tích, thể tích phụ thuộc theo tỉ lệ bản đồ. Khảo sát, phân tích mật độ điểm theo tỉ lệ của bản đồ, chỉ ra sự khác nhau của bản đồ và sơ đồ được phóng to khi hiển thị trên màn hình. Phân tích, làm rõ các điểm giống nhau, khác nhau trong quá trình thành lập, sử dụng bản đồ giấy và bản đồ số. Thông qua các khảo sát và phân tích, giúp chọn và sử dụng bản đồ số có tỉ lệ cần thiết, theo quy định, để các bài toán thiết kế, quy hoạch đảm bảo các yêu cầu kỹ thuật đặt ra. Từ khóa: bản đồ số phục vụ quy hoạch; tỉ lệ của bản đồ số; độ chính xác của bản đồ; mật độ điểm và mức độ khái quát hóa trên bản đồ; độ phóng đại của bản đồ số.
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Pub Date : 2018-09-28DOI: 10.31814/STCE.NUCE2018-12(6)-07
Lê Hoàng Sơn, Thái Hồng Nam, Nguyễn Tuấn Ngọc, Kiều Văn Cẩn
Bài báo này giới thiệu một số loại hình nút giao khác mức “kiểu mới” chưa được sử dụng ở Việt Nam, phân tích những điểm tích cực và hạn chế của chúng. Nhóm tác giả đã tiến hành khảo sát về hình học, lưu lượng và một số thông số của dòng giao thông tại nút Ngã tư Sở để phân tích những ưu, nhược điểm của phương pháp tổ chức hiện trạng, đồng thời áp dụng những loại hình nút “kiểu mới” vào tính toán, tổ chức giao thông cho nút ngã tư này, từ đó chỉ ra được những ưu việt của chúng so với việc tổ chức giao thông hiện tại. Qua việc áp dụng các loại hình nút “kiểu mới” này vào nút giao Ngã tư Sở, nhóm tác giả nhận thấy rằng việc tổ chức giao thông theo các loại hình nút này sẽ góp phần đáng kể trong việc giảm thiểu ùn tắc tại các nút ngã tư ở Hà Nội nói riêng và các đô thị trên cả nước nói chung. Tuy nhiên, cũng cần có sự nghiên cứu kỹ lưỡng về địa hình, đặc điểm giao thông của từng vị trí cụ thể trước khi quyết định loại hình nút giao thông phù hợp nhất. Từ khóa: nút giao phân tuyến hình kim cương; nút giao định hướng; nút giao Ngã tư Sở; cải tạo nút giao.
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