The objective of this review paper is to survey the state of the art on nature-based solutions (N... more The objective of this review paper is to survey the state of the art on nature-based solutions (NBS) in the built environment, which can contribute to a circular economy (CE) and counter the negative impacts of urbanization through the provision of ecosystem services. NBS are discussed here at three different levels: (i) green building materials, including biocomposites with plant-based aggregates; (ii) green building systems, employed for the greening of buildings by incorporating vegetation in their envelope; and (iii) green building sites, emphasizing the value of vegetated open spaces and water-sensitive urban design. After introducing the central concepts of NBS and CE as they are manifested in the built environment, we examine the impacts of urban development and the historical use of materials, systems and sites which can offer solutions to these problems. In the central section of the paper we present a series of case studies illustrating the development and implementation o...
AbstractThe increasing need to calibrate and validate multiscale numerical models cries out for n... more AbstractThe increasing need to calibrate and validate multiscale numerical models cries out for new experimental devices and methodologies. This paper presents an experimental measurement device of...
ABSTRACT This paper describes the development of a fiber reinforced concrete (FRC) unit cell for ... more ABSTRACT This paper describes the development of a fiber reinforced concrete (FRC) unit cell for analyzing concrete structures by executing a multiscale analysis procedure using the theory of homogenization. This was achieved through solving a periodic unit cell problem of the material in order to evaluate its macroscopic properties. Our research describes the creation of an FRC unit cell through the use of concrete paste generic information e.g. the percentage of aggregates, their distribution, and the percentage of fibers in the concrete. The algorithm presented manipulates the percentage and distribution of these aggregates along with fiber weight to create a finite element unit cell model of the FRC which can be used in a multiscale analysis of concrete structures.
La investigación experimental ha demostrado el extraordinario potencial de la adición de fibras c... more La investigación experimental ha demostrado el extraordinario potencial de la adición de fibras cortas a los materiales cementiceos, ya que mejoran significativamente el comportamiento de estructuras de hormigón en los estados límite de servicio y último. Para la simulación del comportamiento no lineal del material en estructuras de hormigón reforzado con fibras se utilizan programas informáticos basados en el método de elementos finitos. Generalmente, las aproximaciones existentes se evalúan en simulaciones de ensayos experimentales de elementos estructurales a pequeña escala, donde los valores de los parámetros de las leyes constitutivas de los materiales se ajustan según el resultado deseado. La utilidad de esta técnica inversa para el diseño estructural es discutible. Precisamente, para evaluar el comportamiento predictivo de dicho enfoque, se organizó una competición a ciegas de simulaciones numéricas. Para ello, se ensayaron hasta rotura, a flexión en tres puntos asimétrica, d...
30th International Symposium on Shock Waves 2, 2017
Internal explosion in an ammunition and explosive (A&E) facility might cause the most dangero... more Internal explosion in an ammunition and explosive (A&E) facility might cause the most dangerous consequences. The blast can spread to all parts of the facility harming personnel in different levels. High pressure can cause lethality due to lung damage. It might also cause building collapse mainly of the structure’s elements right aside the explosion that might turn into debris and rubbels. The secondary fragments of nearby equipment (connected or unconnected) might fly with high velocity. Shock wave moving through the structure and the ground might cause people to be overturned or to fall down with possible injuries or fatalities.
Abstract A detailed Loss of Coolant Accident (LOCA) analysis in an AP1000 NPP was performed, foll... more Abstract A detailed Loss of Coolant Accident (LOCA) analysis in an AP1000 NPP was performed, followed by a definition of the vulnerability analysis principles, and analysis of blast loads and fragments impact created by a nearby explosion. The AP1000 NPP performs excellently to small-break LOCA due to in-structure shock, with the 10 CFR 50.46 Acceptance Criteria fully accomplished. Impulsive dynamic loads resulting from blast waves and fragments impact of GBU-28 (Guided Bomb Unit) were considered for a nearby explosion. We model the structure and the main reactor components using the MSC/Dytran code to obtain accurate internal acceleration levels at critical points. We account for the appropriate blast wave interaction with the soil and the soil interaction with the containment structure, rather than using empirical formulas. The model includes the shielding structure with its concrete base, the support structures for the reactor, the steam generators, and the pressurizer. The combined effect of bomb fragmentation and blast loading was also considered using a cylindrical fragmentation model and the blast model of Kingery-Bulmash, assuming a hemispherical charge. A comprehensive risk assessment methodology composed of four phases was developed. The methodology is comprised of: (I) System analysis, (II) Hazard analysis, (III) Damage assessment, and (IV) Risk analysis of the in-structure shock consequences. Using seismic fragility curves for analysis of the expected failure modes according to explosion events faced difficulties since no published data was found. Adjustments to these fragility curves were made using median acceleration limits on components designed to withstand airplane crash, together with standard deviations taken from the given earthquake fragility tables. The findings reveal that the probabilities of failure of the reactor coolant system components resulting from a GBU-28 nearby hit, namely the pressurizer, the cooling pumps, and valves are quite high (greater than 1∙10−4).
Proceedings of the Eleventh International Conference on Civil, Structural and Environmental Engineering Computing
ABSTRACT An evaluation of three commercial hydro-codes which may be used for the purpose of simul... more ABSTRACT An evaluation of three commercial hydro-codes which may be used for the purpose of simulating the interaction of explosive blasts with RC structures is presented. Firstly, a simple test case with a known prescribed impulse was chosen for the model verification in all three codes. Then, a practical structure design for test validation and parameter calibration was suggested. Computations of TNT charge blasts at varying distances from the structures were performed. A comparison of the results obtained by the codes is presented.
In light of recent terrorist attacks on facilities throughout the world, designers, planners, arc... more In light of recent terrorist attacks on facilities throughout the world, designers, planners, architects, and engineers are beginning to re-visit conventional approaches in the design of military and high-security facilities. Many existing buildings, structures and facilities ...
The objective of this review paper is to survey the state of the art on nature-based solutions (N... more The objective of this review paper is to survey the state of the art on nature-based solutions (NBS) in the built environment, which can contribute to a circular economy (CE) and counter the negative impacts of urbanization through the provision of ecosystem services. NBS are discussed here at three different levels: (i) green building materials, including biocomposites with plant-based aggregates; (ii) green building systems, employed for the greening of buildings by incorporating vegetation in their envelope; and (iii) green building sites, emphasizing the value of vegetated open spaces and water-sensitive urban design. After introducing the central concepts of NBS and CE as they are manifested in the built environment, we examine the impacts of urban development and the historical use of materials, systems and sites which can offer solutions to these problems. In the central section of the paper we present a series of case studies illustrating the development and implementation o...
AbstractThe increasing need to calibrate and validate multiscale numerical models cries out for n... more AbstractThe increasing need to calibrate and validate multiscale numerical models cries out for new experimental devices and methodologies. This paper presents an experimental measurement device of...
ABSTRACT This paper describes the development of a fiber reinforced concrete (FRC) unit cell for ... more ABSTRACT This paper describes the development of a fiber reinforced concrete (FRC) unit cell for analyzing concrete structures by executing a multiscale analysis procedure using the theory of homogenization. This was achieved through solving a periodic unit cell problem of the material in order to evaluate its macroscopic properties. Our research describes the creation of an FRC unit cell through the use of concrete paste generic information e.g. the percentage of aggregates, their distribution, and the percentage of fibers in the concrete. The algorithm presented manipulates the percentage and distribution of these aggregates along with fiber weight to create a finite element unit cell model of the FRC which can be used in a multiscale analysis of concrete structures.
La investigación experimental ha demostrado el extraordinario potencial de la adición de fibras c... more La investigación experimental ha demostrado el extraordinario potencial de la adición de fibras cortas a los materiales cementiceos, ya que mejoran significativamente el comportamiento de estructuras de hormigón en los estados límite de servicio y último. Para la simulación del comportamiento no lineal del material en estructuras de hormigón reforzado con fibras se utilizan programas informáticos basados en el método de elementos finitos. Generalmente, las aproximaciones existentes se evalúan en simulaciones de ensayos experimentales de elementos estructurales a pequeña escala, donde los valores de los parámetros de las leyes constitutivas de los materiales se ajustan según el resultado deseado. La utilidad de esta técnica inversa para el diseño estructural es discutible. Precisamente, para evaluar el comportamiento predictivo de dicho enfoque, se organizó una competición a ciegas de simulaciones numéricas. Para ello, se ensayaron hasta rotura, a flexión en tres puntos asimétrica, d...
30th International Symposium on Shock Waves 2, 2017
Internal explosion in an ammunition and explosive (A&E) facility might cause the most dangero... more Internal explosion in an ammunition and explosive (A&E) facility might cause the most dangerous consequences. The blast can spread to all parts of the facility harming personnel in different levels. High pressure can cause lethality due to lung damage. It might also cause building collapse mainly of the structure’s elements right aside the explosion that might turn into debris and rubbels. The secondary fragments of nearby equipment (connected or unconnected) might fly with high velocity. Shock wave moving through the structure and the ground might cause people to be overturned or to fall down with possible injuries or fatalities.
Abstract A detailed Loss of Coolant Accident (LOCA) analysis in an AP1000 NPP was performed, foll... more Abstract A detailed Loss of Coolant Accident (LOCA) analysis in an AP1000 NPP was performed, followed by a definition of the vulnerability analysis principles, and analysis of blast loads and fragments impact created by a nearby explosion. The AP1000 NPP performs excellently to small-break LOCA due to in-structure shock, with the 10 CFR 50.46 Acceptance Criteria fully accomplished. Impulsive dynamic loads resulting from blast waves and fragments impact of GBU-28 (Guided Bomb Unit) were considered for a nearby explosion. We model the structure and the main reactor components using the MSC/Dytran code to obtain accurate internal acceleration levels at critical points. We account for the appropriate blast wave interaction with the soil and the soil interaction with the containment structure, rather than using empirical formulas. The model includes the shielding structure with its concrete base, the support structures for the reactor, the steam generators, and the pressurizer. The combined effect of bomb fragmentation and blast loading was also considered using a cylindrical fragmentation model and the blast model of Kingery-Bulmash, assuming a hemispherical charge. A comprehensive risk assessment methodology composed of four phases was developed. The methodology is comprised of: (I) System analysis, (II) Hazard analysis, (III) Damage assessment, and (IV) Risk analysis of the in-structure shock consequences. Using seismic fragility curves for analysis of the expected failure modes according to explosion events faced difficulties since no published data was found. Adjustments to these fragility curves were made using median acceleration limits on components designed to withstand airplane crash, together with standard deviations taken from the given earthquake fragility tables. The findings reveal that the probabilities of failure of the reactor coolant system components resulting from a GBU-28 nearby hit, namely the pressurizer, the cooling pumps, and valves are quite high (greater than 1∙10−4).
Proceedings of the Eleventh International Conference on Civil, Structural and Environmental Engineering Computing
ABSTRACT An evaluation of three commercial hydro-codes which may be used for the purpose of simul... more ABSTRACT An evaluation of three commercial hydro-codes which may be used for the purpose of simulating the interaction of explosive blasts with RC structures is presented. Firstly, a simple test case with a known prescribed impulse was chosen for the model verification in all three codes. Then, a practical structure design for test validation and parameter calibration was suggested. Computations of TNT charge blasts at varying distances from the structures were performed. A comparison of the results obtained by the codes is presented.
In light of recent terrorist attacks on facilities throughout the world, designers, planners, arc... more In light of recent terrorist attacks on facilities throughout the world, designers, planners, architects, and engineers are beginning to re-visit conventional approaches in the design of military and high-security facilities. Many existing buildings, structures and facilities ...
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Papers by Erez Gal