The Experts below are selected from a list of 63 Experts worldwide ranked by ideXlab platform

P. Ivanov - One of the best experts on this subject based on the ideXlab platform.

  • Deterministic modelling for microzonation of Sofia — An expected Earthquake scenario
    Acta Geodaetica et Geophysica Hungarica, 2004
    Co-Authors: I. Paskaleva, G. F. Panza, F. Vaccari, P. Ivanov
    Abstract:

    The capital of Bulgaria, Sofia is a growing city with population around 1.22 million. The city is exposed to a high seismic risk since it is placed in the centre of Sofia seismic area. Over the centuries in the town of Sofia the macroseismic intensities have been larger than IX (MSK). A study of the site effects and the microzonation of a part of metropolitan Sofia, based on a modelling of seismic ground motion along three cross sections are presented. Realistic synthetic strong motion waveforms have been computed for an expected scenario Earthquake ( M = 7) applying a hybrid modelling method, based on the modal summation technique and finite differences scheme. The site amplification is determined in terms of response spectra ratio (RSR). A set of time histories and quantities of Earthquake engineering interest are supplied, that allow the definition of six zones characterized by specific response spectra. The results from this study constitute a “database” that describes the ground shaking of the urban area. The synthetic velocigrams are employed to calculate the distribution of the horizontal strain factor Log_10ε, using a simplified relation between particle velocity and velocity of shear waves in the surface layer. It is shown that it is possible to estimate liquefaction susceptibility in terms of standard penetration tests (SPT), $${\bar N}$$ values and initial over burden stress. Using the data for maximum particle velocity and empirical relationships developed from the Northridge Earthquake, 1994 the distributions of the expected pipe breaks and red-tagged buildings for Sofia city are shown.

  • Deterministic modelling for microzonation of Sofia - An expected Earthquake scenario
    Acta Geodaetica et Geophysica Hungarica, 2004
    Co-Authors: I. Paskaleva, G. F. Panza, F. Vaccari, P. Ivanov
    Abstract:

    The capital of Bulgaria, Sofia is a growing city with population around 1.22 million. The city is exposed to a high seismic risk since it is placed in the centre of Sofia seismic area. Over the centuries in the town of Sofia the macroseismic intensities have been larger than IX (MSK). A study of the site effects and the microzonation of a part of metropolitan Sofia, based on a modelling of seismic ground motion along three cross sections are presented. Realistic synthetic strong motion waveforms have been computed for an expected scenario Earthquake (M=7) applying a hybrid modelling method, based on the modal summation technique and finite differences scheme. The site amplification is determined in terms of response spectra ratio (RSR). A set of time histories and quantities of Earthquake engineering interest are supplied, that allow the definition of six zones characterized by specific response spectra. The results from this study constitute a “database” that describes the ground shaking of the urban area. The synthetic velocigrams are employed to calculate the distribution of the horizontal strain factor Log10e using a simplified relation between particle velocity and velocity of shear waves in the surface layer. It is shown that it is possible to estimate liquefaction susceptibility in terms of standard penetration tests (SPT), Nvalues and initial over burden stress. Using the data for maximum particle velocity and empirical relationships developed from the Northridge Earthquake, 1994 the distributions of the expected pipe breaks and red-tagged buildings for Sofia city are shown

Sami Atallah - One of the best experts on this subject based on the ideXlab platform.

  • Natural Disasters and the Gas Pipeline System
    1996
    Co-Authors: Sami Atallah, Sara Saxena, Stanley B Martin, A.b. Willowby, Raymond S Alger
    Abstract:

    Episodic descriptions are provided of the effects of the Loma Prieta Earthquake (1989) on the gas pipeline systems of Pacific Gas & Electric Company and the City of Palo Alto and of the Northridge Earthquake (1994) on Southern California Gas' pipeline system. The emergency response plans and activities of South Carolina Electric & Gas Company during hurricane Hugo (1989) and of City Gas Company of Florida and other small gas companies during hurricane Andrew (1992) are also reviewed. Descriptions of the Great Flood of 1993 and its effects on the operations of Iowa-Illinois Gas & Electric Company and Laclede Gas Company and of the San Jacinto River Floods on the transmission lines of Valero Natural Gas Company are also provided. Local and federal regulatory requirements, and the current practices by the gas industry for dealing with natural disasters, such as through preventive measures (e.g., strapping of water heaters, excess flow valves), and the tracking of weather-related events are described. The important role that preplanning and coordination with the local emergency response bodies and other gas utilities plays during a natural disaster is examined.

  • Natural disasters and the gas pipeline system. Topical report, August 1994-June 1995
    1996
    Co-Authors: Sami Atallah, Sara Saxena, Stanley B Martin, A.b. Willowby, R. Alger
    Abstract:

    Episodic descriptions are provided of the effect of the Loma Prieta Earthquake (1989) on the gas pipeline systems of Pacific Gas & Electric Company and the City of Palo Alto and of the Northridge Earthquake (1994) on Southern California Gas` pipeline system. The emergency response plans and activities of South Carolina Electric & Gas Company during hurricane Hugo (1989) and of City Gas Company of Florida and other small gas companies during hurricane Andrew (1992) are also reviewed. Descriptions of the great Flood of 1993 and its effects on the operations of Iowa-Illinois Gas & Electric Company and Laclede Gas Company and of the San Jacinto River Floods on the transmission lines of Valero Gas Co. are also provided. Local and federal regulatory requirements, and the current practices by the gas industry for dealing with natural disasters, such as through preventive measures (e.g., strapping of water heaters, excess flow valves), and the tracking of weather-related events are described. The important role that preplanning and coordination with the local emergency response bodies and other gas utilities plays during a natural disaster is examined.

Christiam C. Ángel - One of the best experts on this subject based on the ideXlab platform.

  • A comparative study of seismic diaphragm design forces for RC dual system buildings
    Bulletin of Earthquake Engineering, 2020
    Co-Authors: Juan F. Correal, Victor Hidalgo, Juan C. Reyes, Christiam C. Ángel
    Abstract:

    The reinforced concrete (RC) diaphragm damage observed during the Northridge Earthquake (1994) has motivated numerous analytical and experimental studies focused on evaluating the seismic performance of this important building component. The ASCE/SEI 7-16 recently introduced an alternative methodology to determine diaphragm design forces that considered various diaphragm systems. However, this formulation was developed for typical North American structures (on frames or dual systems combined with gravity framing), which substantially differ from other worldwide common typologies that may not include gravity framing. Throughout this study, the accuracy of the existing code provisions and other alternative methods is evaluated by using three-dimensional computer models of eight symmetric-plan reinforced concrete buildings that are between five and 15 stories high and have non-gravity frames (i.e. all frames are part of the seismic force resisting system) for RC-floor systems. These models are subjected to non-linear response history analysis that considers sets of far-field records. Benchmark values, defined as the mean value of the time responses and their dispersion, are compared with the forces of design codes and procedures. General conclusions indicate that existing provisions underestimate diaphragm design forces for all the systems considered, but the results can substantially improve if a low diaphragm reduction factor is used. Alternative procedures capture the magnitude but not the height distribution. Finally, the level of non-linear behavior of the structural elements was verified; beams exhibit high inelastic response, but the overall structure and the vertical elements mostly kept elastic.

Raymond S Alger - One of the best experts on this subject based on the ideXlab platform.

  • Natural Disasters and the Gas Pipeline System
    1996
    Co-Authors: Sami Atallah, Sara Saxena, Stanley B Martin, A.b. Willowby, Raymond S Alger
    Abstract:

    Episodic descriptions are provided of the effects of the Loma Prieta Earthquake (1989) on the gas pipeline systems of Pacific Gas & Electric Company and the City of Palo Alto and of the Northridge Earthquake (1994) on Southern California Gas' pipeline system. The emergency response plans and activities of South Carolina Electric & Gas Company during hurricane Hugo (1989) and of City Gas Company of Florida and other small gas companies during hurricane Andrew (1992) are also reviewed. Descriptions of the Great Flood of 1993 and its effects on the operations of Iowa-Illinois Gas & Electric Company and Laclede Gas Company and of the San Jacinto River Floods on the transmission lines of Valero Natural Gas Company are also provided. Local and federal regulatory requirements, and the current practices by the gas industry for dealing with natural disasters, such as through preventive measures (e.g., strapping of water heaters, excess flow valves), and the tracking of weather-related events are described. The important role that preplanning and coordination with the local emergency response bodies and other gas utilities plays during a natural disaster is examined.

I. Paskaleva - One of the best experts on this subject based on the ideXlab platform.

  • Deterministic modelling for microzonation of Sofia — An expected Earthquake scenario
    Acta Geodaetica et Geophysica Hungarica, 2004
    Co-Authors: I. Paskaleva, G. F. Panza, F. Vaccari, P. Ivanov
    Abstract:

    The capital of Bulgaria, Sofia is a growing city with population around 1.22 million. The city is exposed to a high seismic risk since it is placed in the centre of Sofia seismic area. Over the centuries in the town of Sofia the macroseismic intensities have been larger than IX (MSK). A study of the site effects and the microzonation of a part of metropolitan Sofia, based on a modelling of seismic ground motion along three cross sections are presented. Realistic synthetic strong motion waveforms have been computed for an expected scenario Earthquake ( M = 7) applying a hybrid modelling method, based on the modal summation technique and finite differences scheme. The site amplification is determined in terms of response spectra ratio (RSR). A set of time histories and quantities of Earthquake engineering interest are supplied, that allow the definition of six zones characterized by specific response spectra. The results from this study constitute a “database” that describes the ground shaking of the urban area. The synthetic velocigrams are employed to calculate the distribution of the horizontal strain factor Log_10ε, using a simplified relation between particle velocity and velocity of shear waves in the surface layer. It is shown that it is possible to estimate liquefaction susceptibility in terms of standard penetration tests (SPT), $${\bar N}$$ values and initial over burden stress. Using the data for maximum particle velocity and empirical relationships developed from the Northridge Earthquake, 1994 the distributions of the expected pipe breaks and red-tagged buildings for Sofia city are shown.

  • Deterministic modelling for microzonation of Sofia - An expected Earthquake scenario
    Acta Geodaetica et Geophysica Hungarica, 2004
    Co-Authors: I. Paskaleva, G. F. Panza, F. Vaccari, P. Ivanov
    Abstract:

    The capital of Bulgaria, Sofia is a growing city with population around 1.22 million. The city is exposed to a high seismic risk since it is placed in the centre of Sofia seismic area. Over the centuries in the town of Sofia the macroseismic intensities have been larger than IX (MSK). A study of the site effects and the microzonation of a part of metropolitan Sofia, based on a modelling of seismic ground motion along three cross sections are presented. Realistic synthetic strong motion waveforms have been computed for an expected scenario Earthquake (M=7) applying a hybrid modelling method, based on the modal summation technique and finite differences scheme. The site amplification is determined in terms of response spectra ratio (RSR). A set of time histories and quantities of Earthquake engineering interest are supplied, that allow the definition of six zones characterized by specific response spectra. The results from this study constitute a “database” that describes the ground shaking of the urban area. The synthetic velocigrams are employed to calculate the distribution of the horizontal strain factor Log10e using a simplified relation between particle velocity and velocity of shear waves in the surface layer. It is shown that it is possible to estimate liquefaction susceptibility in terms of standard penetration tests (SPT), Nvalues and initial over burden stress. Using the data for maximum particle velocity and empirical relationships developed from the Northridge Earthquake, 1994 the distributions of the expected pipe breaks and red-tagged buildings for Sofia city are shown