During earthquakes, pounding of adjacent buildings occurs due to their different dynamic characte... more During earthquakes, pounding of adjacent buildings occurs due to their different dynamic characteristics as well as insufficient separation distance between them. Although earthquake loading is commonly considered in structural design, pounding of adjacent buildings is not usually considered and usually causes highly unexpected damages and failures. Pounding effect was numerically investigated in this study, where adjacent buildings were designed to resist lateral earthquake loads without taking into consideration the additional applied force resulting from pounding. Nonlinear dynamic analysis was carried using the Applied Element Method (AEM). Pounding of buildings of different structural systems, different gravity loading and different floor heights was investigated. Dynamic behavior in terms of additional base shear, base bending moments and pounding forces was investigated for different gap distances less than the safe gap distance specified by the Egyptian Code of Practice (ECP...
Angioscopy enables macroscopic pathological diagnosis of cardiovascular diseases from the inside.... more Angioscopy enables macroscopic pathological diagnosis of cardiovascular diseases from the inside. This imaging modality has been intensively directed to characterizing vulnerable coronary plaques. Scoring of plaque color was developed, and based on prospective studies; dark yellow or glistening yellow plaques were proposed as vulnerable ones. Colorimetry apparatus was developed to assess the yellow color of the plaques quantitatively. The effects of lipid-lowering therapies on coronary plaques were confirmed by angioscopy. However, since observation is limited to surface color and morphology, pitfalls of this imaging technology became evident. Dye-staining angioscopy and near-infrared fluorescence angioscopy were developed for molecular imaging, and the latter method was successfully applied to patients. Color fluorescence angioscopy was also established for molecular and chemical basis characterization of vulnerable coronary plaques in both in vitro and in vivo. Drug-eluting stents (DES) reduce coronary restenosis significantly, however, late stent thrombosis (LST) occurs, which requires long-term antiplatelet therapy. Angioscopic grading of neointimal coverage of coronary stent struts was established, and it was revealed that neointimal formation is incomplete and prevalence of LST is higher in DES when compared to bare-metal stent. Many new stents were devised and they are now under experimental or clinical investigations to overcome the shortcomings of the stents that have been employed clinically. Endothelial cells are highly antithrombotic. Neoendothelial cell damage is considered to be caused by friction between the cells and stent struts due to the thin neointima between them that might act as a cushion. Therefore, development of a DES that causes an appropriate thickness (around 100 m) of the neointima is a potential option with which to prevent neoendothelial cell damage and consequent LST while preventing restenosis.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Throughout the past decades, failure of structures threatening the lives of humans had been popul... more Throughout the past decades, failure of structures threatening the lives of humans had been popular whether through structure failure due to human error such as Hyatt Regency walkway collapse, 1981, terrorist attacks on the American embassy attack in Nairobi, Kenya 1998 and the famous 9/11 attacks in 2001 and many more. As a result of these incidents, The Unified Facilities Criteria (UFC) was developed concerning the progressive collapse issues by analyzing different types of structures under column loss and studying the overall structural behavior. However, the (UFC) didn’t scope on the local behavior of the structural components and its connection under column loss. In this research, the main objective is to study the local behavior of the special moment frame connection (SMC) under column loss. A detailed study is conducted on a 3D model fully designed by adopting the strong-column weak-beam approach following the ACI318-14 regulations. Two frames are selected from the designed s...
International Journal of Computational Methods and Experimental Measurements, 2016
Precast concrete components are manufactured in a well-controlled environment. It has been proven... more Precast concrete components are manufactured in a well-controlled environment. It has been proven to show good behaviour under gravity and lateral loads. However, the beam to column connections remain the critical part in the precast concrete structures under the column loss scenario in a progressive collapse scenario. In this paper, different beam to column connections, wet and dry connections, are studied and investigated numerically under the column removal scenario. A detailed model for the different connections is developed using the Applied Element Method (AEM). Different column removal locations are considered in the study to provide a comprehensive assessment. The performance of the connections is studied in terms of ultimate load capacity and rotational ductility. According to the results obtained, a connection enhancement is suggested to increase the resistance of precast concrete structures to progressive collapse.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Journal of Al-Azhar University Engineering Sector, 2017
Precast concrete structures become widely used recently due to high quality of manufacturing as w... more Precast concrete structures become widely used recently due to high quality of manufacturing as well as its good behaviour under gravity .However the most critical part in the precast structures is beam to column connections in precast frame system due to the different variables involved in the assemblages. In this paper a study is carried out on different wet beam column connections under column removal scenario to observe the behaviour of the connections due to progressive collapse. Different column removal locations with different frame arrangements is studied. The Applied Element Method is implemented in the study to construct a 3D detailed model of the studied connections by using Extreme Loading of Structures Software. The performance of the connections is presented in terms beam, column and joint behaviour. Maximum beam deflection, rotation and internal axial force, normal and shear stresses of the connection reinforcement as well as the column behaviour in terms of rotation and internal axial forces are discussed. From the results obtained an enhancement design is suggested for the failed connections and studied its effect in resisting the local failure due to column removal.
International Journal of Computer Applications, Nov 18, 2014
During earthquakes, pounding of adjacent buildings occurs due to their different dynamic characte... more During earthquakes, pounding of adjacent buildings occurs due to their different dynamic characteristics as well as insufficient separation distance between them. Although earthquake loading is commonly considered in structural design, pounding of adjacent buildings is not usually considered and usually causes highly unexpected damages and failures. Pounding effect was numerically investigated in this study, where adjacent buildings were designed to resist lateral earthquake loads without taking into consideration the additional applied force resulting from pounding. Nonlinear dynamic analysis was carried using the Applied Element Method (AEM). Pounding of buildings of different structural systems, different gravity loading and different floor heights was investigated. Dynamic behavior in terms of additional base shear, base bending moments and pounding forces was investigated for different gap distances less than the safe gap distance specified by the Egyptian Code of Practice (ECP). Effect of gap distance, building's dynamic characteristics, building's height and gravity loads on additional straining actions due to impact was discussed.
During earthquakes, pounding of adjacent buildings occurs due to their different dynamic characte... more During earthquakes, pounding of adjacent buildings occurs due to their different dynamic characteristics as well as insufficient separation distance between them. Although earthquake loading is commonly considered in structural design, pounding of adjacent buildings is not usually considered and usually causes highly unexpected damages and failures. Pounding effect was numerically investigated in this study, where adjacent buildings were designed to resist lateral earthquake loads without taking into consideration the additional applied force resulting from pounding. Nonlinear dynamic analysis was carried using the Applied Element Method (AEM). Pounding of buildings of different structural systems, different gravity loading and different floor heights was investigated. Dynamic behavior in terms of additional base shear, base bending moments and pounding forces was investigated for different gap distances less than the safe gap distance specified by the Egyptian Code of Practice (ECP...
Angioscopy enables macroscopic pathological diagnosis of cardiovascular diseases from the inside.... more Angioscopy enables macroscopic pathological diagnosis of cardiovascular diseases from the inside. This imaging modality has been intensively directed to characterizing vulnerable coronary plaques. Scoring of plaque color was developed, and based on prospective studies; dark yellow or glistening yellow plaques were proposed as vulnerable ones. Colorimetry apparatus was developed to assess the yellow color of the plaques quantitatively. The effects of lipid-lowering therapies on coronary plaques were confirmed by angioscopy. However, since observation is limited to surface color and morphology, pitfalls of this imaging technology became evident. Dye-staining angioscopy and near-infrared fluorescence angioscopy were developed for molecular imaging, and the latter method was successfully applied to patients. Color fluorescence angioscopy was also established for molecular and chemical basis characterization of vulnerable coronary plaques in both in vitro and in vivo. Drug-eluting stents (DES) reduce coronary restenosis significantly, however, late stent thrombosis (LST) occurs, which requires long-term antiplatelet therapy. Angioscopic grading of neointimal coverage of coronary stent struts was established, and it was revealed that neointimal formation is incomplete and prevalence of LST is higher in DES when compared to bare-metal stent. Many new stents were devised and they are now under experimental or clinical investigations to overcome the shortcomings of the stents that have been employed clinically. Endothelial cells are highly antithrombotic. Neoendothelial cell damage is considered to be caused by friction between the cells and stent struts due to the thin neointima between them that might act as a cushion. Therefore, development of a DES that causes an appropriate thickness (around 100 m) of the neointima is a potential option with which to prevent neoendothelial cell damage and consequent LST while preventing restenosis.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Throughout the past decades, failure of structures threatening the lives of humans had been popul... more Throughout the past decades, failure of structures threatening the lives of humans had been popular whether through structure failure due to human error such as Hyatt Regency walkway collapse, 1981, terrorist attacks on the American embassy attack in Nairobi, Kenya 1998 and the famous 9/11 attacks in 2001 and many more. As a result of these incidents, The Unified Facilities Criteria (UFC) was developed concerning the progressive collapse issues by analyzing different types of structures under column loss and studying the overall structural behavior. However, the (UFC) didn’t scope on the local behavior of the structural components and its connection under column loss. In this research, the main objective is to study the local behavior of the special moment frame connection (SMC) under column loss. A detailed study is conducted on a 3D model fully designed by adopting the strong-column weak-beam approach following the ACI318-14 regulations. Two frames are selected from the designed s...
International Journal of Computational Methods and Experimental Measurements, 2016
Precast concrete components are manufactured in a well-controlled environment. It has been proven... more Precast concrete components are manufactured in a well-controlled environment. It has been proven to show good behaviour under gravity and lateral loads. However, the beam to column connections remain the critical part in the precast concrete structures under the column loss scenario in a progressive collapse scenario. In this paper, different beam to column connections, wet and dry connections, are studied and investigated numerically under the column removal scenario. A detailed model for the different connections is developed using the Applied Element Method (AEM). Different column removal locations are considered in the study to provide a comprehensive assessment. The performance of the connections is studied in terms of ultimate load capacity and rotational ductility. According to the results obtained, a connection enhancement is suggested to increase the resistance of precast concrete structures to progressive collapse.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Journal of Al-Azhar University Engineering Sector, 2017
Precast concrete structures become widely used recently due to high quality of manufacturing as w... more Precast concrete structures become widely used recently due to high quality of manufacturing as well as its good behaviour under gravity .However the most critical part in the precast structures is beam to column connections in precast frame system due to the different variables involved in the assemblages. In this paper a study is carried out on different wet beam column connections under column removal scenario to observe the behaviour of the connections due to progressive collapse. Different column removal locations with different frame arrangements is studied. The Applied Element Method is implemented in the study to construct a 3D detailed model of the studied connections by using Extreme Loading of Structures Software. The performance of the connections is presented in terms beam, column and joint behaviour. Maximum beam deflection, rotation and internal axial force, normal and shear stresses of the connection reinforcement as well as the column behaviour in terms of rotation and internal axial forces are discussed. From the results obtained an enhancement design is suggested for the failed connections and studied its effect in resisting the local failure due to column removal.
International Journal of Computer Applications, Nov 18, 2014
During earthquakes, pounding of adjacent buildings occurs due to their different dynamic characte... more During earthquakes, pounding of adjacent buildings occurs due to their different dynamic characteristics as well as insufficient separation distance between them. Although earthquake loading is commonly considered in structural design, pounding of adjacent buildings is not usually considered and usually causes highly unexpected damages and failures. Pounding effect was numerically investigated in this study, where adjacent buildings were designed to resist lateral earthquake loads without taking into consideration the additional applied force resulting from pounding. Nonlinear dynamic analysis was carried using the Applied Element Method (AEM). Pounding of buildings of different structural systems, different gravity loading and different floor heights was investigated. Dynamic behavior in terms of additional base shear, base bending moments and pounding forces was investigated for different gap distances less than the safe gap distance specified by the Egyptian Code of Practice (ECP). Effect of gap distance, building's dynamic characteristics, building's height and gravity loads on additional straining actions due to impact was discussed.
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