Golubka Nechevska-Cvetanovska, Artur Roshi, J. Bojadjieva, Jordan Bojadjiev, Zoran Trajcevski
To explore the possibilities and benefits of using CFRP (Carbon Fibre Reinforced Polymers) in strengthening RC building columns, quasi-static tests (compression and bending) were carried out at the Institute of Earthquake Engineering and Engineering Seismology IZIIS, Skopje by variation of concrete class, reinforcement percentage and by using various strengthening technologies. Some recommendations and outcomes regarding the approach, technology and conclusions drawn from practical application of these materials, are given. Based on the analysis of values obtained from nonlinear static and nonlinear time history analyses, it can be concluded that the ductility capacity for displacement of model strengthened with CFRP is greater by 60 %, while its strength capacity is greater by 7.7 % when compared to the values obtained for the model without CFRP. It can generally be concluded that CFRP systems are a very practical tool for strengthening and retrofitting concrete structures, as they can extensively improve flexural strengthening, shear strengthening, column confinement, and ductility.
{"title":"Quasi-static tests on RC building columns strengthened with CFRP","authors":"Golubka Nechevska-Cvetanovska, Artur Roshi, J. Bojadjieva, Jordan Bojadjiev, Zoran Trajcevski","doi":"10.14256/jce.3087.2020","DOIUrl":"https://doi.org/10.14256/jce.3087.2020","url":null,"abstract":"To explore the possibilities and benefits of using CFRP (Carbon Fibre Reinforced Polymers) in strengthening RC building columns, quasi-static tests (compression and bending) were carried out at the Institute of Earthquake Engineering and Engineering Seismology IZIIS, Skopje by variation of concrete class, reinforcement percentage and by using various strengthening technologies. Some recommendations and outcomes regarding the approach, technology and conclusions drawn from practical application of these materials, are given. Based on the analysis of values obtained from nonlinear static and nonlinear time history analyses, it can be concluded that the ductility capacity for displacement of model strengthened with CFRP is greater by 60 %, while its strength capacity is greater by 7.7 % when compared to the values obtained for the model without CFRP. It can generally be concluded that CFRP systems are a very practical tool for strengthening and retrofitting concrete structures, as they can extensively improve flexural strengthening, shear strengthening, column confinement, and ductility.","PeriodicalId":50415,"journal":{"name":"Gradevinar","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66968975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents the pilot project of application of recycled aggregate during construction of a new day hospital in Zadar. The project included the demolition of an existing hospital building and the use of generated construction waste as recycled aggregate in the construction of a part of the building. The 16/32 mm fraction of aggregate was obtained by mechanical processing of the generated waste which was then tested in accordance with the HRN EN 206 and HRN EN 12620 standards. Four concrete mixes were prepared
介绍了再生骨料在扎达尔新建日间医院建设中应用的试点项目。该项目包括拆除现有的医院建筑，并在建筑的一部分中使用产生的建筑废物作为再生骨料。通过对产生的废物进行机械处理获得16/32 mm骨料分数，然后根据HRN EN 206和HRN EN 12620标准进行测试。配制了四种混凝土配合比
{"title":"Construction of a new day hospital in Zadar using recycled aggregate concrete","authors":"A. Baričević, Dragan Kovač, Katarina Didulica","doi":"10.14256/JCE.3233.2021","DOIUrl":"https://doi.org/10.14256/JCE.3233.2021","url":null,"abstract":"This paper presents the pilot project of application of recycled aggregate during construction of a new day hospital in Zadar. The project included the demolition of an existing hospital building and the use of generated construction waste as recycled aggregate in the construction of a part of the building. The 16/32 mm fraction of aggregate was obtained by mechanical processing of the generated waste which was then tested in accordance with the HRN EN 206 and HRN EN 12620 standards. Four concrete mixes were prepared","PeriodicalId":50415,"journal":{"name":"Gradevinar","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66969132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The paper presents commonly used methodology for assessing damage of water supply networks after a seismic event. The methodology relies on deriving and applying so-called vulnerability function. An overview of the existing vulnerability functions is given together with parameters, primarily related to soil deformations, which are influencing the assessment. Also, a critical review of the possibility of their use is given. Finally, by using two approaches, the estimated number of damages, with associated repair costs, is given for the water supply network of the City of Petrinja after the earthquake on December 29, 2020. With a total of 3 800 new damages, it is estimated that the total repair costs are around HRK 28 million. The accuracy of these estimates should be verified after detailed collection and processing of relevant data in accordance with the given guidelines.
{"title":"Damage assessment of water supply networks due to seismic events using vulnerability functions","authors":"S. Lakušić","doi":"10.14256/jce.3185.2021","DOIUrl":"https://doi.org/10.14256/jce.3185.2021","url":null,"abstract":"The paper presents commonly used methodology for assessing damage of water supply networks after a seismic event. The methodology relies on deriving and applying so-called vulnerability function. An overview of the existing vulnerability functions is given together with parameters, primarily related to soil deformations, which are influencing the assessment. Also, a critical review of the possibility of their use is given. Finally, by using two approaches, the estimated number of damages, with associated repair costs, is given for the water supply network of the City of Petrinja after the earthquake on December 29, 2020. With a total of 3 800 new damages, it is estimated that the total repair costs are around HRK 28 million. The accuracy of these estimates should be verified after detailed collection and processing of relevant data in accordance with the given guidelines.","PeriodicalId":50415,"journal":{"name":"Gradevinar","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66968667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The article describes the testing of poles for electric power transmission lines, which are made of centrifugally-cast concrete and ultra-high strength concrete, and which are prestressed with Carbon Fibre Reinforced Polymer tendons (CFRP). The presented results of pole ultimate load testing suggest the potential for usage of this construction product, particularly in aggressive environments with high probability of steel corrosion. Part of the tested poles had shear reinforcement in the form of confined Glass Fibre Reinforced Polymer (GFRP) grid, while one share of samples had no shear reinforcement, but the concrete matrix was strengthened with synthetic macro fibres. A review is given on similar product testing, calculation methods, and guidance is provided for further research.
{"title":"Centrifugally-cast concrete poles with non-metallic reinforcement","authors":"","doi":"10.14256/jce.3246.2021","DOIUrl":"https://doi.org/10.14256/jce.3246.2021","url":null,"abstract":"The article describes the testing of poles for electric power transmission lines, which are made of centrifugally-cast concrete and ultra-high strength concrete, and which are prestressed with Carbon Fibre Reinforced Polymer tendons (CFRP). The presented results of pole ultimate load testing suggest the potential for usage of this construction product, particularly in aggressive environments with high probability of steel corrosion. Part of the tested poles had shear reinforcement in the form of confined Glass Fibre Reinforced Polymer (GFRP) grid, while one share of samples had no shear reinforcement, but the concrete matrix was strengthened with synthetic macro fibres. A review is given on similar product testing, calculation methods, and guidance is provided for further research.","PeriodicalId":50415,"journal":{"name":"Gradevinar","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66969259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Considering the huge differences in the prediction and organization of equations available in the literature, this paper aims at developing a reliable equation including mass and stiffness parameters. Microtremor (ambient vibration) measurements were taken from 23 RC buildings and their fundamental periods were compared to the dynamic analysis results. Building models were then calibrated to account for the infill wall effect. After that, 156 RC buildings were 3D modelled and their dynamic analysis results were used to calibrate the proposed fundamental period equation.
{"title":"A simplified fundamental period equation for RC buildings","authors":"A. Yiğit, B. Erdil, İ. Akkaya","doi":"10.14256/jce.3080.2020","DOIUrl":"https://doi.org/10.14256/jce.3080.2020","url":null,"abstract":"Considering the huge differences in the prediction and organization of equations available in the literature, this paper aims at developing a reliable equation including mass and stiffness parameters. Microtremor (ambient vibration) measurements were taken from 23 RC buildings and their fundamental periods were compared to the dynamic analysis results. Building models were then calibrated to account for the infill wall effect. After that, 156 RC buildings were 3D modelled and their dynamic analysis results were used to calibrate the proposed fundamental period equation.","PeriodicalId":50415,"journal":{"name":"Gradevinar","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66968943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Procedures for estimating damage and remaining bearing capacity of RC structures after fire are presented in the paper. The paper describes the effect of fire on structures, the danger it poses for the loss of human lives, and financial losses it may generate. The damage to structural RC elements of a column, beam, slab, wall, and connection details, is presented in the paper. Although RC elements are generally considered to be fire resistant, their physical and mechanical characteristics are greatly influenced by temperature, while the bearing capacity before and after fire can be determined through a number of different methods that are presented in the paper. An overview of condition assessment for RC structures after fire is proposed, and methodology for taking further action is presented.
{"title":"Overview of research on fire effects in RC elements and assessment of RC structures after fire","authors":"S. Lakušić","doi":"10.14256/jce.3196.2021","DOIUrl":"https://doi.org/10.14256/jce.3196.2021","url":null,"abstract":"Procedures for estimating damage and remaining bearing capacity of RC structures after fire are presented in the paper. The paper describes the effect of fire on structures, the danger it poses for the loss of human lives, and financial losses it may generate. The damage to structural RC elements of a column, beam, slab, wall, and connection details, is presented in the paper. Although RC elements are generally considered to be fire resistant, their physical and mechanical characteristics are greatly influenced by temperature, while the bearing capacity before and after fire can be determined through a number of different methods that are presented in the paper. An overview of condition assessment for RC structures after fire is proposed, and methodology for taking further action is presented.","PeriodicalId":50415,"journal":{"name":"Gradevinar","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66968843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Balasubramanian, E. Gopal, Dhivya Kamaraj, S. Ponnaiah, Prakash Periakaruppan
This study investigates the effects of fire, cooling methods, and cover thickness, on the behaviour (strength and ductility) of 12-mm diameter rebars embedded in mortars with river sand (RS) substitutes such as granite powder and manufactured sand, with 30 and 50 mm cover thickness. Beyond 500°C, thermal stress induced random spalling of mortar cover, and tension test results showed strength decrement and ductility increment of rebars for air cooling, while the vice versa was observed for water quenching.
{"title":"Rebar properties in sand-substitute mortars after exposure to high temperatures","authors":"J. Balasubramanian, E. Gopal, Dhivya Kamaraj, S. Ponnaiah, Prakash Periakaruppan","doi":"10.14256/JCE.2931.2020","DOIUrl":"https://doi.org/10.14256/JCE.2931.2020","url":null,"abstract":"This study investigates the effects of fire, cooling methods, and cover thickness, on the behaviour (strength and ductility) of 12-mm diameter rebars embedded in mortars with river sand (RS) substitutes such as granite powder and manufactured sand, with 30 and 50 mm cover thickness. Beyond 500°C, thermal stress induced random spalling of mortar cover, and tension test results showed strength decrement and ductility increment of rebars for air cooling, while the vice versa was observed for water quenching.","PeriodicalId":50415,"journal":{"name":"Gradevinar","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66968122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ASA (Advanced Seismic Assessment) module is a post-earthquake technical intervention service, developed over the years by the EUCENTRE Foundation through a series of national and European pilot projects, field exercises, and direct experience, after the latest major seismic events that struck Italy since 2009. The system consists of a service managed at the headquarters in Pavia for the development of damage scenarios, and of a mobile unit for the on-site damage assessments. After the Central Italy earthquake, the Foundation has been involved for about eight months in several activities, including provision of technical support to the Italian Department of Civil Protection, joint reconnaissance with internationally acknowledged research institutes.
{"title":"EUCENTRE and seismic emergency: technical preparedness activities and response after the central Italy earthquake","authors":"C. Casarotti, S. Peloso, B. Borzi, A. Pavese","doi":"10.14256/JCE.3049.2020","DOIUrl":"https://doi.org/10.14256/JCE.3049.2020","url":null,"abstract":"The ASA (Advanced Seismic Assessment) module is a post-earthquake technical intervention service, developed over the years by the EUCENTRE Foundation through a series of national and European pilot projects, field exercises, and direct experience, after the latest major seismic events that struck Italy since 2009. The system consists of a service managed at the headquarters in Pavia for the development of damage scenarios, and of a mobile unit for the on-site damage assessments. After the Central Italy earthquake, the Foundation has been involved for about eight months in several activities, including provision of technical support to the Italian Department of Civil Protection, joint reconnaissance with internationally acknowledged research institutes.","PeriodicalId":50415,"journal":{"name":"Gradevinar","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66968849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Estimation of costs is important in every phase of realisation of construction projects. However, the influence of cost estimation is the highest in early phases as it is then that the decision about accepting the job or withdrawing from the project is made. The quantity of data available in initial phases of the project is smaller compared to subsequent phases, which affects accuracy of cost estimation in such early phases. A research making use of artificial intelligence to estimate construction costs of integral road bridges is presented in the paper. The estimation model is prepared by means of neural networks. The best neural network model has proven to be highly accurate in the estimation of costs based on the mean absolute error, which amounts to 13.40 %.
{"title":"Use of artificial intelligence for estimating cost of integral bridges","authors":"S. Lakušić","doi":"10.14256/JCE.2831.2019","DOIUrl":"https://doi.org/10.14256/JCE.2831.2019","url":null,"abstract":"Estimation of costs is important in every phase of realisation of construction projects. However, the influence of cost estimation is the highest in early phases as it is then that the decision about accepting the job or withdrawing from the project is made. The quantity of data available in initial phases of the project is smaller compared to subsequent phases, which affects accuracy of cost estimation in such early phases. A research making use of artificial intelligence to estimate construction costs of integral road bridges is presented in the paper. The estimation model is prepared by means of neural networks. The best neural network model has proven to be highly accurate in the estimation of costs based on the mean absolute error, which amounts to 13.40 %.","PeriodicalId":50415,"journal":{"name":"Gradevinar","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66967241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The operation of the Karašnica Water Treatment Plant, forming part of the water system in Ilijaš Municipality, in Bosnia and Herzegovina, is analysed in the paper. Two distinct water treatment lines are described and analysed. The first line consists of an internal circular settling tank and rapid sand gravity filters, while the second line consists of an external circular settling tank and pressure filters. In order to evaluate operating efficiency, a tour of the system facilities was made, interviews with the employees were conducted, the existing documentation was examined, and additional physicochemical and bacteriological analyses of appropriate water samples were conducted. Following analysis of all available data, appropriate conclusions and significant recommendations were made toward more efficient operation of the water treatment plant.
{"title":"Analysis of Water Treatment Plant Operation in Ilijaš Municipality","authors":"S. Lakušić","doi":"10.14256/JCE.2913.2020","DOIUrl":"https://doi.org/10.14256/JCE.2913.2020","url":null,"abstract":"The operation of the Karašnica Water Treatment Plant, forming part of the water system in Ilijaš Municipality, in Bosnia and Herzegovina, is analysed in the paper. Two distinct water treatment lines are described and analysed. The first line consists of an internal circular settling tank and rapid sand gravity filters, while the second line consists of an external circular settling tank and pressure filters. In order to evaluate operating efficiency, a tour of the system facilities was made, interviews with the employees were conducted, the existing documentation was examined, and additional physicochemical and bacteriological analyses of appropriate water samples were conducted. Following analysis of all available data, appropriate conclusions and significant recommendations were made toward more efficient operation of the water treatment plant.","PeriodicalId":50415,"journal":{"name":"Gradevinar","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66967861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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