The paper deals with the methods of software optimization of the concrete structure in terms of environmental issues, durability, and cost. It links to previously developed software tool that enables multi-criteria optimization of a 1 m2 one-way slab. A feasibility study focused on the optimization of larger structural units, and it analyses and compares methods of concrete structures optimization in terms of environmental impacts, durability, and life-cycle cost.
{"title":"Optimization of Reinforced Concrete Structures in Terms of Environmental Impacts, Durability and Cost","authors":"Anna Horáková, A. Kohoutková, I. Broukalová","doi":"10.4028/p-kv2eck","DOIUrl":"https://doi.org/10.4028/p-kv2eck","url":null,"abstract":"The paper deals with the methods of software optimization of the concrete structure in terms of environmental issues, durability, and cost. It links to previously developed software tool that enables multi-criteria optimization of a 1 m2 one-way slab. A feasibility study focused on the optimization of larger structural units, and it analyses and compares methods of concrete structures optimization in terms of environmental impacts, durability, and life-cycle cost.","PeriodicalId":17714,"journal":{"name":"Key Engineering Materials","volume":"13 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140232592","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}
One of the most effective and common ways of an increasing the punching shear capacity of the flat slabs is using of shear reinforcement. An important limit during the design is the determination of the maximum punching shear resistance. The fact that the calculation of such an important value is still clearly empirical has met with criticism from many experts in recent years. Consequently, a new design model for the calculation of the maximum punching shear resistance, based on the critical shear crack theory was developed. The second generation of the Eurocode 2 (prEC2) introduces a more accurate and sophisticated design model for the determination of the upper limit of the punching shear capacity and considers several parameters. The main aim of this paper is to describe the new methodology of calculation of the maximum punching shear strength and the parameters that could influence it. The paper deals also with an assessment of the suitability of new model by comparing it with experimental results, that have been selected from a database of specimens that failed by punching at the level of VR,max.
{"title":"Limits for the Punching Shear Capacity of the Flat Slabs Reinforced with Transverse Reinforcement","authors":"Natália Gregušová, J. Halvonik","doi":"10.4028/p-2yaeaj","DOIUrl":"https://doi.org/10.4028/p-2yaeaj","url":null,"abstract":"One of the most effective and common ways of an increasing the punching shear capacity of the flat slabs is using of shear reinforcement. An important limit during the design is the determination of the maximum punching shear resistance. The fact that the calculation of such an important value is still clearly empirical has met with criticism from many experts in recent years. Consequently, a new design model for the calculation of the maximum punching shear resistance, based on the critical shear crack theory was developed. The second generation of the Eurocode 2 (prEC2) introduces a more accurate and sophisticated design model for the determination of the upper limit of the punching shear capacity and considers several parameters. The main aim of this paper is to describe the new methodology of calculation of the maximum punching shear strength and the parameters that could influence it. The paper deals also with an assessment of the suitability of new model by comparing it with experimental results, that have been selected from a database of specimens that failed by punching at the level of VR,max.","PeriodicalId":17714,"journal":{"name":"Key Engineering Materials","volume":"18 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140234816","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}
This paper describes an experimental investigation of the behaviour of anchors precast in Ultra High-Performance Fiber-Reinforced Concrete (UHPFRC) under static loading. Initially, the current state of the art and related experimental studies are briefly mentioned. The next part of the paper is devoted to an experimental program aimed at describing the anchorage in cement composite UHPFRC in more detail. A total of 45 pull-out tests were performed. The tests investigated the effect of the fiber quantity in volume in the UHPFRC matrix (vf), the effective embedment depth of the anchor (hef) and the position of the anchor in the mould during concreting. Finally, the results are documented, the failure mode and the shape of the concrete cone, load-displacement curves and summary tables are presented. The paper concludes with a discussion of the results and further directions for solving the problem.
{"title":"Experimental Study of Cast in Anchors Embedded in UHPFRC","authors":"Jan Prchal, L. Vráblík","doi":"10.4028/p-r6h4w7","DOIUrl":"https://doi.org/10.4028/p-r6h4w7","url":null,"abstract":"This paper describes an experimental investigation of the behaviour of anchors precast in Ultra High-Performance Fiber-Reinforced Concrete (UHPFRC) under static loading. Initially, the current state of the art and related experimental studies are briefly mentioned. The next part of the paper is devoted to an experimental program aimed at describing the anchorage in cement composite UHPFRC in more detail. A total of 45 pull-out tests were performed. The tests investigated the effect of the fiber quantity in volume in the UHPFRC matrix (vf), the effective embedment depth of the anchor (hef) and the position of the anchor in the mould during concreting. Finally, the results are documented, the failure mode and the shape of the concrete cone, load-displacement curves and summary tables are presented. The paper concludes with a discussion of the results and further directions for solving the problem.","PeriodicalId":17714,"journal":{"name":"Key Engineering Materials","volume":"80 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140232320","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}
Adam Citek, M. Kryštov, Karel Hurtig, Vojtech Sulc, M. Foglar, D. Čítek
The resistance of structures to the effects of explosions is very current issue in these days. During explosion structures are subjected to extreme dynamic local loads and it is necessary to the structure and its reinforcement for this type of loading. In UHPFRC the reinforcement is evenly distributed throughout the structure in the form of dispersed steel fibres. Based on the knowledges of excellent mechanical properties of both steel and UHPFRC, there is an assumption that an appropriate combination of these materials in the sense of composite constructions should result in significantly less damage to the structure in the case of explosion. The paper is focused on the process of production of testing specimens intended for blast resistance tests. The first part of the paper describes tests elements and goals of the experiment. In the next part of the paper the design and material properties of the used concrete mixtures are described. Then production in the sense of formwork preparation and casting is described. At the end of the article, there is a brief comparison of the results achieved for specimens from UHPFRC and reference NSC.
{"title":"Production of Steel-Concrete Composite UHPFRC Elements for Experimental Tests of the Blast Resistance","authors":"Adam Citek, M. Kryštov, Karel Hurtig, Vojtech Sulc, M. Foglar, D. Čítek","doi":"10.4028/p-oyi5pk","DOIUrl":"https://doi.org/10.4028/p-oyi5pk","url":null,"abstract":"The resistance of structures to the effects of explosions is very current issue in these days. During explosion structures are subjected to extreme dynamic local loads and it is necessary to the structure and its reinforcement for this type of loading. In UHPFRC the reinforcement is evenly distributed throughout the structure in the form of dispersed steel fibres. Based on the knowledges of excellent mechanical properties of both steel and UHPFRC, there is an assumption that an appropriate combination of these materials in the sense of composite constructions should result in significantly less damage to the structure in the case of explosion. The paper is focused on the process of production of testing specimens intended for blast resistance tests. The first part of the paper describes tests elements and goals of the experiment. In the next part of the paper the design and material properties of the used concrete mixtures are described. Then production in the sense of formwork preparation and casting is described. At the end of the article, there is a brief comparison of the results achieved for specimens from UHPFRC and reference NSC.","PeriodicalId":17714,"journal":{"name":"Key Engineering Materials","volume":"43 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140234348","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}
Vojtech Sulc, M. Foglar, R. Hájek, J. Kolísko, Adam Citek, Karel Hurtig
Blast performance of concrete and ultra-high performance fiber concrete (UHPFRC) has been subject to numerous publications in the past decades. The enhanced force-deflection diagram of fiber concrete and ultra-high performance fiber concrete provide massive increase on the protective function of these materials compared to regular concrete. Nevertheless, concrete spalling cannot be fully avoided even when using UHPFRC. The next step for harmful debris ejection prevention can be supplementing the concrete specimens with steel slabs. The steel slab will not just hold the debris, but can, if properly bonded with concrete, contribute to the load bearing capacity as steel-concrete composite structure. This paper presents an overview of recent experiments on blast resistance of steel-concrete composite slabs. In total 6 pairs of specimens (dimension 1.000/1.000/150mm) were prepared, 6 specimens using regular concrete and 6 specimens using UHPFRC. One pair of specimens was reinforced by a steel mesh at 30mm cover from the soffit, one pair was supplemented by a steel plate bonded with 4 studs in the corners, at the complementary specimen pair, the concrete was also covered with a steel plate at the side subjected to blast loading, in the case of the further pair of specimens, the steel plates were connected by steel bars arranged in a mesh 150/150mm. The final 2 pairs represented steel-concrete composite slabs, in the first case, the shear studs were supplemented with a steel mesh (according to provisions of the European standard for steel-concrete composite structures), in the last case, the shear studs were replaced by a shear plate. All specimens were subjected to the same contact blast loading. The paper presents the experimental arrangement, the achieved results and a brief discussion on the structural behavior.
{"title":"Investigations on Blast Performance of Steel-Concrete Composite Structures","authors":"Vojtech Sulc, M. Foglar, R. Hájek, J. Kolísko, Adam Citek, Karel Hurtig","doi":"10.4028/p-4zmz3d","DOIUrl":"https://doi.org/10.4028/p-4zmz3d","url":null,"abstract":"Blast performance of concrete and ultra-high performance fiber concrete (UHPFRC) has been subject to numerous publications in the past decades. The enhanced force-deflection diagram of fiber concrete and ultra-high performance fiber concrete provide massive increase on the protective function of these materials compared to regular concrete. Nevertheless, concrete spalling cannot be fully avoided even when using UHPFRC. The next step for harmful debris ejection prevention can be supplementing the concrete specimens with steel slabs. The steel slab will not just hold the debris, but can, if properly bonded with concrete, contribute to the load bearing capacity as steel-concrete composite structure. This paper presents an overview of recent experiments on blast resistance of steel-concrete composite slabs. In total 6 pairs of specimens (dimension 1.000/1.000/150mm) were prepared, 6 specimens using regular concrete and 6 specimens using UHPFRC. One pair of specimens was reinforced by a steel mesh at 30mm cover from the soffit, one pair was supplemented by a steel plate bonded with 4 studs in the corners, at the complementary specimen pair, the concrete was also covered with a steel plate at the side subjected to blast loading, in the case of the further pair of specimens, the steel plates were connected by steel bars arranged in a mesh 150/150mm. The final 2 pairs represented steel-concrete composite slabs, in the first case, the shear studs were supplemented with a steel mesh (according to provisions of the European standard for steel-concrete composite structures), in the last case, the shear studs were replaced by a shear plate. All specimens were subjected to the same contact blast loading. The paper presents the experimental arrangement, the achieved results and a brief discussion on the structural behavior.","PeriodicalId":17714,"journal":{"name":"Key Engineering Materials","volume":"222 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140233612","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}
When analyzing slender columns, the second-generation Eurocode FprEN [2] recommends the calculation of the bending moment envelope, which consists of both first-order and second-order moments. This paper presents the aforementioned calculation method for both braced and bracing columns, utilizing a comprehensive “general” nonlinear approach.
{"title":"Theory of the Second Order for Braced and Bracing Columns","authors":"L. Fillo, V. Benko","doi":"10.4028/p-etak9w","DOIUrl":"https://doi.org/10.4028/p-etak9w","url":null,"abstract":"When analyzing slender columns, the second-generation Eurocode FprEN [2] recommends the calculation of the bending moment envelope, which consists of both first-order and second-order moments. This paper presents the aforementioned calculation method for both braced and bracing columns, utilizing a comprehensive “general” nonlinear approach.","PeriodicalId":17714,"journal":{"name":"Key Engineering Materials","volume":"42 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140234234","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}
Massive concrete structures are exposed to the risk of high temperatures due to cement hydration. In accordance with requirements for sustainable development, the clinker content in commonly produced cements is reduced and mixed cements are developed and gradually introduced into production. The development of temperatures in massive foundation structures made of concrete containing modern mixed cements is the subject of an experimental program. Its results are evaluated from the point of view of the final properties of the concrete, but also from the point of view of the possibilities of concrete production and implementation technologies. In conclusions, general recommendations are formulated for the design of concrete mixtures for application in massive structures.
{"title":"Temperature Measurement in Massive Concrete Structures","authors":"Vit Nemcic, Jan L. Vítek, Jiří Lukeš","doi":"10.4028/p-b0ztq2","DOIUrl":"https://doi.org/10.4028/p-b0ztq2","url":null,"abstract":"Massive concrete structures are exposed to the risk of high temperatures due to cement hydration. In accordance with requirements for sustainable development, the clinker content in commonly produced cements is reduced and mixed cements are developed and gradually introduced into production. The development of temperatures in massive foundation structures made of concrete containing modern mixed cements is the subject of an experimental program. Its results are evaluated from the point of view of the final properties of the concrete, but also from the point of view of the possibilities of concrete production and implementation technologies. In conclusions, general recommendations are formulated for the design of concrete mixtures for application in massive structures.","PeriodicalId":17714,"journal":{"name":"Key Engineering Materials","volume":"261 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140233409","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}
{"title":"Concrete Structures and Structural Elements in Modern Construction","authors":"Šárka Nenadálová, Petra Johová, Kateřina Hamplová","doi":"10.4028/b-txs3pt","DOIUrl":"https://doi.org/10.4028/b-txs3pt","url":null,"abstract":"","PeriodicalId":17714,"journal":{"name":"Key Engineering Materials","volume":"330 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140232682","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}
Kristýna Richterová, Pavel Heinrich, Jan Harš, Petr Bíly
The construction industry is undergoing another revolution, including the field of masonry construction. New materials and products for masonry are constantly being developed and construction details and implementation procedures are being resolved. Digitization and the introduction of automation in the masonry process (in prefabrication halls or on-site robotic bricklaying) are also an integral part of the development of the masonry construction industry. The topic of the following paper is a summary of problematic construction details of masonry buildings, i.e., the solution of the plinth console, the solution of the building opening, the bearing of lintels on the masonry and the bearing of the ceiling structure on the masonry wall. The results of laboratory tests are presented – the load-bearing capacity of the jamb of the building opening (accessory bricks / cut bricks in the jamb) and the load-bearing capacity of the lintel placed on the accessory edge brick. Furthermore, the paper deals with the construction of masonry buildings in the 21st century, including the first results of a compressive load test on masonry walls made of precast small-format units. The conclusion of the paper points out the importance of correct design details of masonry buildings before their application (programming) in software controlling the automated masonry process.
{"title":"Aspects Affecting the Quality of Masonry Buildings and Innovations in Masonry","authors":"Kristýna Richterová, Pavel Heinrich, Jan Harš, Petr Bíly","doi":"10.4028/p-zun5wb","DOIUrl":"https://doi.org/10.4028/p-zun5wb","url":null,"abstract":"The construction industry is undergoing another revolution, including the field of masonry construction. New materials and products for masonry are constantly being developed and construction details and implementation procedures are being resolved. Digitization and the introduction of automation in the masonry process (in prefabrication halls or on-site robotic bricklaying) are also an integral part of the development of the masonry construction industry. The topic of the following paper is a summary of problematic construction details of masonry buildings, i.e., the solution of the plinth console, the solution of the building opening, the bearing of lintels on the masonry and the bearing of the ceiling structure on the masonry wall. The results of laboratory tests are presented – the load-bearing capacity of the jamb of the building opening (accessory bricks / cut bricks in the jamb) and the load-bearing capacity of the lintel placed on the accessory edge brick. Furthermore, the paper deals with the construction of masonry buildings in the 21st century, including the first results of a compressive load test on masonry walls made of precast small-format units. The conclusion of the paper points out the importance of correct design details of masonry buildings before their application (programming) in software controlling the automated masonry process.","PeriodicalId":17714,"journal":{"name":"Key Engineering Materials","volume":"335 2‐3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140232841","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}
This paper deals with failure modes of a steel-concrete-steel sandwich loaded by pure in-plane shear. Current research together with the developed models imply that increase of reinforcement ratio leads to decrease of ductility and possibly to change a failure mode from yielding of steel in tension to crushing of concrete in compression which results in brittle failure. In order to give a reader basic information about in-plane shear behavior of a steel-concrete-steel sandwich, an analytical model is introduced. Japanese experimental program that researched a behavior of SCS panels with reinforcement ratio 2.3%, 3.2% and 4.5% is also shown. In addition to the effect of changing the reinforcement ratio, the experimental program also investigated the effect of the transverse steel plate on the ductility of test panels with a degree of reinforcement of 3.2%. The next chapter describes the methodology used by the author to model the individual parts of the model, the loads, and especially the method of supporting the model. This is followed by the presentation of the results of the analysis on the calibration and extrapolation models. Finally, a discussion is conducted on the agreement of the analysis results on the calibration models with the Japanese experimental results, followed by an evaluation of the analysis results on the extrapolation models. According to the results on the extrapolation models the critical degree of reinforcement at which a change in the failure mode of the structure occurs under in-plane shear loading is around 13%.
{"title":"Dependence of a Steel-concrete-Steel Sandwich Structure Behavior under Pure In-Plane Shear Loading on the Reinforcement Ratio","authors":"Roman Kubát, Petr Bíly","doi":"10.4028/p-egknc1","DOIUrl":"https://doi.org/10.4028/p-egknc1","url":null,"abstract":"This paper deals with failure modes of a steel-concrete-steel sandwich loaded by pure in-plane shear. Current research together with the developed models imply that increase of reinforcement ratio leads to decrease of ductility and possibly to change a failure mode from yielding of steel in tension to crushing of concrete in compression which results in brittle failure. In order to give a reader basic information about in-plane shear behavior of a steel-concrete-steel sandwich, an analytical model is introduced. Japanese experimental program that researched a behavior of SCS panels with reinforcement ratio 2.3%, 3.2% and 4.5% is also shown. In addition to the effect of changing the reinforcement ratio, the experimental program also investigated the effect of the transverse steel plate on the ductility of test panels with a degree of reinforcement of 3.2%. The next chapter describes the methodology used by the author to model the individual parts of the model, the loads, and especially the method of supporting the model. This is followed by the presentation of the results of the analysis on the calibration and extrapolation models. Finally, a discussion is conducted on the agreement of the analysis results on the calibration models with the Japanese experimental results, followed by an evaluation of the analysis results on the extrapolation models. According to the results on the extrapolation models the critical degree of reinforcement at which a change in the failure mode of the structure occurs under in-plane shear loading is around 13%.","PeriodicalId":17714,"journal":{"name":"Key Engineering Materials","volume":"32 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140231746","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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