Pub Date : 2021-01-01DOI: 10.21608/erjsh.2021.314212
A. Ahmed, O. Kamal, O. El-Mahdy, M. El-Diasity
. Linear and non-linear structural analyses can be solved using the finite element method (FEM) and other numerical techniques. A new applied element method (AEM) that can predict with a higher degree of accuracy the continuum and discrete behavior of structures has recently been developed. In AEM, elements sharing the same surface will have connectivity springs even if the shared surfaces are only a portion of the surface. The collapse phases of structures by using AEM can be tracked and monitored. In the current research, the application of AEM is demonstrated by a non-linear dynamic analysis for reinforced concrete (RC) columns and slabs subjected to blast loading. The available experimental works carried out by other researchers to study the impact of close-in blast loading on RC members are used for verification. A good correlation between the experimental and numerical results has been achieved.
{"title":"Analysis of RC Columns and Slabs Subjected to Blast Loadings","authors":"A. Ahmed, O. Kamal, O. El-Mahdy, M. El-Diasity","doi":"10.21608/erjsh.2021.314212","DOIUrl":"https://doi.org/10.21608/erjsh.2021.314212","url":null,"abstract":". Linear and non-linear structural analyses can be solved using the finite element method (FEM) and other numerical techniques. A new applied element method (AEM) that can predict with a higher degree of accuracy the continuum and discrete behavior of structures has recently been developed. In AEM, elements sharing the same surface will have connectivity springs even if the shared surfaces are only a portion of the surface. The collapse phases of structures by using AEM can be tracked and monitored. In the current research, the application of AEM is demonstrated by a non-linear dynamic analysis for reinforced concrete (RC) columns and slabs subjected to blast loading. The available experimental works carried out by other researchers to study the impact of close-in blast loading on RC members are used for verification. A good correlation between the experimental and numerical results has been achieved.","PeriodicalId":159365,"journal":{"name":"Engineering Research Journal (Shoubra)","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133657822","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 : 2021-01-01DOI: 10.21608/erjsh.2021.314213
Abeer A. Mohamed, Mohamed S. Issa, Ahmed Akl Mahmoud
. There is a shortage in researches that discuss the effect of fire on building and represent solution for structural elements that exposed to fire [1-19]. Improving the fire resistance for beams, requires studying the response of reinforcing steel and concrete under fire attack. Concrete has a good behavior under fire due to its low thermal conductivity and non-combustibility. Concrete can act as protective cover to steel reinforcement. To understand the thermo-mechanical response of reinforced concrete beams under fire, experimental researches have been carried out to investigate the performance, resistance, and residual strength of beams under elevated temperature [14,15]. There is a lack of numerical studies addresses these types of analysis. This paper numerically investigates the fire performance of reinforced concrete beams subjected to fire exposure. A series of models of RC beams has been studied. Firstly, RC beams were studied under fire exposure on three surfaces following the temperature time history by ISO 834 standard fire curve. Secondly, studying heat transfer in RC beams and its effects on concrete and reinforcement steel with changing concrete cover and many factors through a parametric study. A finite element model using ANSYS program was carried out and accomplish a good correlation with the experimental results in both thermal and structural performance. The element type used for concrete in thermal analysis is Solid 70 while Link 33 is the element type used to represent reinforcing steel. The validated finite element model was used to conduct a parametric study on the behavior of RC shallow beams under fire. Materials nonlinearity was taken into consideration because there effects of the heat transfer in concrete, thermal expansion, and yielding of reinforcing steel. In addition, investigate the residual capacity of RC beams. The parametric study investigates the effects of: (1) concrete compressive strength (f cu ); (2) concrete cover (d`); (3) steel reinforcement yield strength (f y ); (4) ratio of main reinforcement ( %); (5) specific heat of the outer layers (C); (6) thermal conductivity of the outer layers (K); (7) voids area percentage in beam cross-section; (8) shear –span to depth ratio (a/d); and (9) compression reinforcement steel ratio ( ` %).
{"title":"Behavior of Reinforced Concrete Beams Exposed to Fire","authors":"Abeer A. Mohamed, Mohamed S. Issa, Ahmed Akl Mahmoud","doi":"10.21608/erjsh.2021.314213","DOIUrl":"https://doi.org/10.21608/erjsh.2021.314213","url":null,"abstract":". There is a shortage in researches that discuss the effect of fire on building and represent solution for structural elements that exposed to fire [1-19]. Improving the fire resistance for beams, requires studying the response of reinforcing steel and concrete under fire attack. Concrete has a good behavior under fire due to its low thermal conductivity and non-combustibility. Concrete can act as protective cover to steel reinforcement. To understand the thermo-mechanical response of reinforced concrete beams under fire, experimental researches have been carried out to investigate the performance, resistance, and residual strength of beams under elevated temperature [14,15]. There is a lack of numerical studies addresses these types of analysis. This paper numerically investigates the fire performance of reinforced concrete beams subjected to fire exposure. A series of models of RC beams has been studied. Firstly, RC beams were studied under fire exposure on three surfaces following the temperature time history by ISO 834 standard fire curve. Secondly, studying heat transfer in RC beams and its effects on concrete and reinforcement steel with changing concrete cover and many factors through a parametric study. A finite element model using ANSYS program was carried out and accomplish a good correlation with the experimental results in both thermal and structural performance. The element type used for concrete in thermal analysis is Solid 70 while Link 33 is the element type used to represent reinforcing steel. The validated finite element model was used to conduct a parametric study on the behavior of RC shallow beams under fire. Materials nonlinearity was taken into consideration because there effects of the heat transfer in concrete, thermal expansion, and yielding of reinforcing steel. In addition, investigate the residual capacity of RC beams. The parametric study investigates the effects of: (1) concrete compressive strength (f cu ); (2) concrete cover (d`); (3) steel reinforcement yield strength (f y ); (4) ratio of main reinforcement ( %); (5) specific heat of the outer layers (C); (6) thermal conductivity of the outer layers (K); (7) voids area percentage in beam cross-section; (8) shear –span to depth ratio (a/d); and (9) compression reinforcement steel ratio ( ` %).","PeriodicalId":159365,"journal":{"name":"Engineering Research Journal (Shoubra)","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130482039","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 : 2019-10-01DOI: 10.21608/erjsh.2019.314536
F. Beshara, O. El-Mahdy, Ahmed Akl Mahmoud, M. Abbass
Progressive collapse potential studies are performed on two-dimensional R.C frames with different reinforcement details under the effect of interior column removal. This study aims to determine the effect of seismic detailing on the structural resistance and behavior of RC frames during progressive collapse event. The R.C frames and reinforcement details would be designed according to Egyptian Code ECP-203 [1]. In this study, two prototype frames were executed from concrete structure and were designed. The first frames F1 is designed with non-seismic reinforcement detail. The second frame F2 is designed with seismic rebar detail. Nonlinear software, used for modeling R.C frames, is extreme loading for structures (ELS). The numerical technique is based on the applied element method with suitable stress-strain relations for concrete and steel. It is found that frame with seismic detail improve the frame resistance against progressive collapse event by 40-45% more than the non-seismic detail in all response stages. The load-steel strain curves and the cracking patterns are also compared for the two frames.
{"title":"Seismic Design Effect on the Progressive Collapse Potential of R.C. Frames","authors":"F. Beshara, O. El-Mahdy, Ahmed Akl Mahmoud, M. Abbass","doi":"10.21608/erjsh.2019.314536","DOIUrl":"https://doi.org/10.21608/erjsh.2019.314536","url":null,"abstract":"Progressive collapse potential studies are performed on two-dimensional R.C frames with different reinforcement details under the effect of interior column removal. This study aims to determine the effect of seismic detailing on the structural resistance and behavior of RC frames during progressive collapse event. The R.C frames and reinforcement details would be designed according to Egyptian Code ECP-203 [1]. In this study, two prototype frames were executed from concrete structure and were designed. The first frames F1 is designed with non-seismic reinforcement detail. The second frame F2 is designed with seismic rebar detail. Nonlinear software, used for modeling R.C frames, is extreme loading for structures (ELS). The numerical technique is based on the applied element method with suitable stress-strain relations for concrete and steel. It is found that frame with seismic detail improve the frame resistance against progressive collapse event by 40-45% more than the non-seismic detail in all response stages. The load-steel strain curves and the cracking patterns are also compared for the two frames.","PeriodicalId":159365,"journal":{"name":"Engineering Research Journal (Shoubra)","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126433859","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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