Pub Date : 2022-12-01DOI: 10.59382/j-ibst.2022.vi.vol4-3
Sỹ Hùng Mai
Thank to the rapid development of computer technology, optimization design has been increasingly widely applied in all areas of life. In structural optimization, due to the variety and even contradiction between the desired goals of design engineers, multi-objective optimization attracts more and more attention from scientists. In this paper, the author presents the multi-objective optimization design problem for steel truss with two basic objectives: the truss mass and the horizontal displacement of the top of the truss is minimized. The design variables are the cross-sectional areas of the structure that are in the defined ranges. Direct analysis is used to capture the nonlinear behavior as well as calculate the maximum load-carrying capacity of the structure. The optimization problem set up above is solved by NSGA-II (Non-dominated sorting GA-II) algorithm. A 47-bar planar truss is studied to illustrate the optimal design problem. The results show that the NSGA-II algorithm is very effective in solving the given optimization problem.
{"title":"TỐI ƯU ĐA MỤC TIÊU GIÀN THÉP PHI TUYẾN CÓ BIẾN THIẾT KẾ\u0000LIÊN TỤC BẰNG THUẬT TOÁN NSGA-II","authors":"Sỹ Hùng Mai","doi":"10.59382/j-ibst.2022.vi.vol4-3","DOIUrl":"https://doi.org/10.59382/j-ibst.2022.vi.vol4-3","url":null,"abstract":"Thank to the rapid development of computer technology, optimization design has been increasingly widely applied in all areas of life. In structural optimization, due to the variety and even contradiction between the desired goals of design engineers, multi-objective optimization attracts more and more attention from scientists. In this paper, the author presents the multi-objective optimization design problem for steel truss with two basic objectives: the truss mass and the horizontal displacement of the top of the truss is minimized. The design variables are the cross-sectional areas of the structure that are in the defined ranges. Direct analysis is used to capture the nonlinear behavior as well as calculate the maximum load-carrying capacity of the structure. The optimization problem set up above is solved by NSGA-II (Non-dominated sorting GA-II) algorithm. A 47-bar planar truss is studied to illustrate the optimal design problem. The results show that the NSGA-II algorithm is very effective in solving the given optimization problem.","PeriodicalId":350876,"journal":{"name":"Vietnam Institute for Building Science and Technology","volume":"201 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124401925","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 : 2022-12-01DOI: 10.59382/j-ibst.2022.v.vol4-1
H. Nguyễn
The horizontal load greatly affects the horizontal displacement of the top of the reinforced concrete frame, especially for the frame with small stiffness. In high-rise buildings, it is necessary to check whether the horizontal displacement of the top of the building and the story drift is satisfied or not. This paper introduces the investigation of the influence of lateral loads on the horizontal displacement of the top of the reinforced concrete flat frame with regard to material nonlinearities using Lira-Sapr software. Therefrom, comment on the difference between the analysis of reinforced concrete frames with regard to material nonlinearity with the analysis according to the elastic.
{"title":"Tính toán chuyển vị ngang của khung BTCT có xét đến vật liệu phi tuyến bằng phần mềm Lira-Sapr 2017","authors":"H. Nguyễn","doi":"10.59382/j-ibst.2022.v.vol4-1","DOIUrl":"https://doi.org/10.59382/j-ibst.2022.v.vol4-1","url":null,"abstract":"The horizontal load greatly affects the horizontal displacement of the top of the reinforced concrete frame, especially for the frame with small stiffness. In high-rise buildings, it is necessary to check whether the horizontal displacement of the top of the building and the story drift is satisfied or not. This paper introduces the investigation of the influence of lateral loads on the horizontal displacement of the top of the reinforced concrete flat frame with regard to material nonlinearities using Lira-Sapr software. Therefrom, comment on the difference between the analysis of reinforced concrete frames with regard to material nonlinearity with the analysis according to the elastic.","PeriodicalId":350876,"journal":{"name":"Vietnam Institute for Building Science and Technology","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127657091","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 : 2022-12-01DOI: 10.59382/j-ibst.2022.vi.vol4-1
H. Nguyễn
The horizontal load greatly affects the horizontal displacement of the top of the reinforced concrete frame, especially for the frame with small stiffness. In high-rise buildings, it is necessary to check whether the horizontal displacement of the top of the building and the story drift is satisfied or not. This paper introduces the investigation of the influence of lateral loads on the horizontal displacement of the top of the reinforced concrete flat frame with regard to material nonlinearities using Lira-Sapr software. Therefrom, comment on the difference between the analysis of reinforced concrete frames with regard to material nonlinearity with the analysis according to the elastic.
{"title":"Tính toán chuyển vị ngang của khung phẳng bê tông cốt thép có kể đến phi tuyến vật liệu bằng phần mềm Lira-Sapr 2017","authors":"H. Nguyễn","doi":"10.59382/j-ibst.2022.vi.vol4-1","DOIUrl":"https://doi.org/10.59382/j-ibst.2022.vi.vol4-1","url":null,"abstract":"The horizontal load greatly affects the horizontal displacement of the top of the reinforced concrete frame, especially for the frame with small stiffness. In high-rise buildings, it is necessary to check whether the horizontal displacement of the top of the building and the story drift is satisfied or not. This paper introduces the investigation of the influence of lateral loads on the horizontal displacement of the top of the reinforced concrete flat frame with regard to material nonlinearities using Lira-Sapr software. Therefrom, comment on the difference between the analysis of reinforced concrete frames with regard to material nonlinearity with the analysis according to the elastic.","PeriodicalId":350876,"journal":{"name":"Vietnam Institute for Building Science and Technology","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132814198","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 : 2022-12-01DOI: 10.59382/j-ibst.2022.vi.vol4-6
Thị Như Ý Lê, Minh Sơn Lê, Ngọc Trí Huỳnh Nguyễn, Khánh Sơn Nguyễn
In this paper, authors present the experimental studies of rheological properties of high performance concrete. In general, rheological properties including viscosity and yeild stress report the workability of concrete material after mixing step. Authors used a coaxial with vane type rheometer in laboratory to measure the rotational moment of the prepared HPC material. Obtained results showed the compressive strength of such HPC around 120 MPa after 28 days of curing period. Measured vicosity and yeild stress increases over time in the period of 0-100 minutes. 70 minutes after mixing, the studied mixture of HPC lost the workability considering the large variation of both vicosity and yeild stress values.
{"title":"THỰC NGHIỆM DÙNG LƯU BIẾN KẾ THEO DÕI SỰ BIẾN THIÊN CÁC THÔNG \u0000SỐ ĐỘ NHỚT, NGƯỠNG CHẢY CỦA VỮA BÊ-TÔNG TÍNH NĂNG CAO","authors":"Thị Như Ý Lê, Minh Sơn Lê, Ngọc Trí Huỳnh Nguyễn, Khánh Sơn Nguyễn","doi":"10.59382/j-ibst.2022.vi.vol4-6","DOIUrl":"https://doi.org/10.59382/j-ibst.2022.vi.vol4-6","url":null,"abstract":"In this paper, authors present the experimental studies of rheological properties of high performance concrete. In general, rheological properties including viscosity and yeild stress report the workability of concrete material after mixing step. Authors used a coaxial with vane type rheometer in laboratory to measure the rotational moment of the prepared HPC material. Obtained results showed the compressive strength of such HPC around 120 MPa after 28 days of curing period. Measured vicosity and yeild stress increases over time in the period of 0-100 minutes. 70 minutes after mixing, the studied mixture of HPC lost the workability considering the large variation of both vicosity and yeild stress values.","PeriodicalId":350876,"journal":{"name":"Vietnam Institute for Building Science and Technology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131382941","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 : 2022-12-01DOI: 10.59382/j-ibst.2022.vi.vol4-2
Văn Thuyết Ngô
Fiber reinforced elastomeric isolator (FREI) is a relatively new laminated elastomeric isolator and is expected to reduce the damage for mid and low-rise buildings under earthquakes. It has been studied and developed with two types: bonded fiber reinforced elastomeric isolator (B-FREI) and unbonded fiber reinforced elastomeric isolator (U-FREI). In this study, the response of a reinforced concrete frame building supported on U-FREIs under the action of various ground motions of recorded real earthquakes in the past is investigated by finite element analysis using SAP2000 software. Result is to determine the hysteresis loops shown the base shear - horizontal displacement curves of the U-FREI supported the base-isolated building under the action of various earthquakes.
{"title":"KHẢO SÁT ĐƯỜNG QUAN HỆ LỰC CẮT - CHUYỂN VỊ NGANG CỦA GỐI \u0000CÁCH CHẤN ĐÀN HỒI CỐT SỢI TRONG CÔNG TRÌNH CÁCH CHẤN ĐÁY \u0000CHỊU ĐỘNG ĐẤT","authors":"Văn Thuyết Ngô","doi":"10.59382/j-ibst.2022.vi.vol4-2","DOIUrl":"https://doi.org/10.59382/j-ibst.2022.vi.vol4-2","url":null,"abstract":"Fiber reinforced elastomeric isolator (FREI) is a relatively new laminated elastomeric isolator and is expected to reduce the damage for mid and low-rise buildings under earthquakes. It has been studied and developed with two types: bonded fiber reinforced elastomeric isolator (B-FREI) and unbonded fiber reinforced elastomeric isolator (U-FREI). In this study, the response of a reinforced concrete frame building supported on U-FREIs under the action of various ground motions of recorded real earthquakes in the past is investigated by finite element analysis using SAP2000 software. Result is to determine the hysteresis loops shown the base shear - horizontal displacement curves of the U-FREI supported the base-isolated building under the action of various earthquakes.","PeriodicalId":350876,"journal":{"name":"Vietnam Institute for Building Science and Technology","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126420874","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 : 1900-01-01DOI: 10.59382/j-ibst.2022.vi.vol4-8
Việt Anh Phạm, Đức Mạnh Nguyễn, Thiết Trung Lê
The earth pressure acting on the retaining wall is usually based on Rankine's limit equilibrium theory and Coulomb's solid sliding mass equilibrium theory. Both methods assume that the backfills can extend to a sufficient distance for the failure plane to fully develop. Therefore, these approaches cannot account for the influence of the backfill width behind the wall. In practice there are many cases of narrow backfill behind the wall. For example, reinforced walls are built in front of stabilized walls or rock, or structures with deep excavations are built near existing underground structures in urban areas. In these cases, the narrow backfill has a significant effect on the full development of a failure wedge according to Rankine's or Coulomb's theory. In this paper, the active earth pressure acting on the wall with a narrow backfill is determined based on Coulomb's theory. The results of the paper show that the earth pressure acting on the wall is significantly reduced when the soil width behind the wall is narrow. This result can be applied in real design cases.
{"title":"ÁP LỰC ĐẤT LÊN TƯỜNG CHẮN VỚI BỀ RỘNG ĐẤT SAU TƯỜNG BỊ GIỚI HẠN","authors":"Việt Anh Phạm, Đức Mạnh Nguyễn, Thiết Trung Lê","doi":"10.59382/j-ibst.2022.vi.vol4-8","DOIUrl":"https://doi.org/10.59382/j-ibst.2022.vi.vol4-8","url":null,"abstract":"The earth pressure acting on the retaining wall is usually based on Rankine's limit equilibrium theory and Coulomb's solid sliding mass equilibrium theory. Both methods assume that the backfills can extend to a sufficient distance for the failure plane to fully develop. Therefore, these approaches cannot account for the influence of the backfill width behind the wall. In practice there are many cases of narrow backfill behind the wall. For example, reinforced walls are built in front of stabilized walls or rock, or structures with deep excavations are built near existing underground structures in urban areas. In these cases, the narrow backfill has a significant effect on the full development of a failure wedge according to Rankine's or Coulomb's theory. In this paper, the active earth pressure acting on the wall with a narrow backfill is determined based on Coulomb's theory. The results of the paper show that the earth pressure acting on the wall is significantly reduced when the soil width behind the wall is narrow. This result can be applied in real design cases.","PeriodicalId":350876,"journal":{"name":"Vietnam Institute for Building Science and Technology","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128945618","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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