Miyamoto International Inc.

Los Angeles, CA, United States

Miyamoto International Inc.

Los Angeles, CA, United States

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Miyamoto H.K.,Tokyo Institute of Technology | Gilani A.S.J.,Miyamoto International Inc. | Wada A.,Tokyo Institute of Technology | Ariyaratana C.,University of Illinois at Urbana - Champaign
Earthquake Spectra | Year: 2011

An innovative design using steel special moment frames sized per building code requirements for strength and viscous dampers to control story drift ratios results in longer period structures that limit floor accelerations with excellent performance in design-level earthquakes. However, the response of this design to extreme seismic events is not well understood. This is due to the lack of: a) limit state data for dampers, and b) data on the response of the system when subjected to large earthquakes. To address these issues, analytical investigation of the limit states of dampers was performed and the performance of the model was correlated with experimental data. This model was then implemented in a group of archetypes subjected to collapse-level loading. Analysis showed that this design had satisfactory performance when subjected to extreme seismic events. Additional significant improvement in performance was obtained with an enhanced damper design and with a damper safety factor of 1.3. © 2011, Earthquake Engineering Research Institute.


Miyamoto H.K.,Tokyo Institute of Technology | Miyamoto H.K.,Miyamoto International Inc. | Gilani A.S.J.,Miyamoto International Inc. | Wada A.,Tokyo Institute of Technology | Ariyaratana C.,University of Illinois at Urbana - Champaign
Earthquake Engineering and Structural Dynamics | Year: 2010

Fluid viscous dampers are used to control story drifts and member forces in structures during earthquake events. These elements provide satisfactory performance at the design-level or maximum considered earthquake. However, buildings using fluid viscous dampers have not been subjected to very large earthquakes with intensities greater than the design and maximum considered events. Furthermore, an extensive database of viscous damper performance during large seismic events does not exist. To address these issues, a comprehensive analytical and experimental investigation was conducted to determine the performance of damped structures subjected to large earthquakes. A critical component of this research was the development and verification of a detailed viscous damper mathematical model that incorporates limit states. The development of this model and the laboratory and simulation results conclude good correlation with the new model and the damper limit states and provide superior results compared with the typical damper model when considering near collapse evaluation of structures. © 2010 John Wiley & Sons, Ltd.


Crosier J.,Miyamoto International Inc. | Hannah M.,University of Canterbury | Mukai D.,University of Wyoming
Bulletin of the New Zealand Society for Earthquake Engineering | Year: 2010

On September 8, a team investigated damage to industrial structures in Christchurch due to the Darfield Earthquake. While there was very little damage to structures regardless of age and framing system, damage to steel storage racks varied from no damage to complete collapse. This paper reports on the observations about the damage to steel racks, reviews pertinent design standards, and makes some preliminary conclusions about the performance of steel storage racks in the Darfield earthquake.


Miyamoto H.K.,Miyamoto International Inc. | Gilani A.S.J.,Miyamoto International Inc.
Geotechnical and Structural Engineering Congress 2016 - Proceedings of the Joint Geotechnical and Structural Engineering Congress 2016 | Year: 2016

In the past earthquakes, heritage buildings have sustained severe damage and collapse in recent earthquakes, including in Italy (2009), Haiti (2010), and New Zealand (2011). For these buildings, the main vertical and lateral load bearing members are typically use variations of unreinforced masonry stone/rubble walls. These walls have little ductility and are susceptible to in-plane and out-of-plane failures that can result in building collapse. The situation is more pronounced in Haiti for heritage structures due to poor quality of design and workmanship. Heritage buildings were significantly damages in Haiti in past earthquakes (including the 2010 event). A proposed mitigation strategy combining seismic isolation and superstructure intervention was used to upgrade selected cathedrals in Haiti. The proposed method significantly reduces the level of seismic excitation acting on the existing walls and limits the superstructure retrofit, and thus preserves the historical features of the structures. Application of this technique to two cathedrals in Haiti is presented. © ASCE.


Miyamoto H.K.,Miyamoto International Inc. | Gilani A.S.J.,Miyamoto International Inc. | Wong K.,Miyamoto International Inc.
Earthquake Spectra | Year: 2011

The January 2010 Haiti earthquake resulted in over 230,000 deaths, affected 3 million people, and damaged or collapsed over 200,000 structures. An unprecedented earthquake damage assessment project by a joint operation of the Haitian Ministry of Public Works, the United Nations Office of Project Services, the Pan American Development Foundation, and the authors was undertaken with three strategic goals: (1) rapid damage assessment, (2) reconstruction database development, and (3) upgrade the technical capabilities of Haitian engineers. A modified version of the Applied Technology Council's ATC-20 technical platform, accounting for Haitian building design, was developed. As part of this program, PDA-based data collection techniques and qualityassurance programs were implemented, and approximately 600 Haitian engineers were trained. As of March 2011, approximately 400,000 buildings had been inspected. This database was used to develop: (1) repair strategies for yellow-tagged structures, and (2) reparability, reconstruction, and demolition assessments or red-tagged structures. This program could also be extended as a platform for a seismic damage evaluation and reconstruction strategies in other parts of the world. © 2011, Earthquake Engineering Research Institute.


Gilani A.S.J.,Miyamoto International Inc. | Miyamoto H.K.,Miyamoto International Inc.
Improving the Seismic Performance of Existing Buildings and other Structures 2015 - Proceedings of the 2nd ATC and SEI Conference on Improving the Seismic Performance of Existing Buildings and Other Structures | Year: 2015

Under the auspices of the World Bank, a multi-step risk assessment project has been recently completed for metropolitan Manila, Philippines, The country's primary commercial and business center, the 11th most populous metropolis in the world, with 12 million. This area is susceptible to multihazard natural disasters such as earthquakes, floods, and typhoons. To address this vulnerability, a risk assessment and mitigation program was undertaken. A prioritization and seismic retrofit program was developed and focused on public schools and hospitals that have suffered disproportional damage and casualties in past disasters worldwide. The key steps in the program were to: (1) prioritize vulnerable structures, (2) conduct cost-benefit analysis to assess retrofit options, and (3) prepare a seismic retrofitting guidelines including design examples and details. Approximately, 4,000 structures were evaluated. The probabilistic evaluation platform was utilized and retrofit options were developed based on the state of art but simple seismic retrofit methods and modified for local construction. © 2015 ASCE and ATC.


Miyamoto H.K.,Miyamoto International Inc. | Gilani A.S.J.,Miyamoto International Inc.
Improving the Seismic Performance of Existing Buildings and other Structures 2015 - Proceedings of the 2nd ATC and SEI Conference on Improving the Seismic Performance of Existing Buildings and Other Structures | Year: 2015

Performance based design with seismic protection devices such as viscous dampers have fundamentally altered the landscape of earthquake engineering and design. Structures designed and built without such devices typically use a code-prescribed design that implies extensive structural damage, loss of operation, and likely replacement at design-level earthquake. In contrast, performance based design incorporating earthquake protection devices leads to a combination of best engineering practice and reducing life-cycle costs. These devices are robust, cost-effective, and have a proven exceptional performance record in past earthquakes. In most cases, initial cost of their utilization is neutralized by reduction in cost of other structural members. The long-term performance is the key parameter used for evaluation. Structures properly designed with these devices will likely only require minimum post-earthquake inspection and can be fully operational within hours of a seismic event. When utilized for critical structures, such performance reduces the need for use of natural resources by eliminating post-earthquake repair or reconstruction and thus improving the community resiliency. Example cases are presented. © 2015 ASCE and ATC.


Gilani A.S.J.,Miyamoto International Inc. | Miyamoto H.K.,Miyamoto International Inc.
Improving the Seismic Performance of Existing Buildings and other Structures 2015 - Proceedings of the 2nd ATC and SEI Conference on Improving the Seismic Performance of Existing Buildings and Other Structures | Year: 2015

Historic and heritage have sustained severe damage and collapse in recent earthquakes, including in Italy (2009), Haiti (2010), and New Zealand (2011). The same has been in case in California in previous earthquakes. The main vertical and lateral load bearing members for these buildings are typically comprised of unreinforced masonry walls. These walls have experienced both in-plane and out-of-plane failures leading to the collapse of the structures. Given that the walls have little lateral capacity, it is critical to limit the input forces acting on them. In addition, these structures do not have a well-defined load path or diaphragm for seismic loading. A proposed mitigation strategy combining seismic isolation and superstructure intervention is discussed to address these deficiencies. Advanced nonlinear global and local finite element analysis is used to assess the efficiency of the proposed retrofit. The proposed method significantly reduces the level of seismic excitation acting on the existing walls and limits the superstructure retrofit, and thus preserves the historical features of the structures. Application of this technique to Miragoane Cathedrals in Haiti is presented construction. © 2015 ASCE and ATC.


Miyamoto H.K.,Miyamoto International Inc. | Gilani A.S.J.,Miyamoto International Inc.
NCEE 2014 - 10th U.S. National Conference on Earthquake Engineering: Frontiers of Earthquake Engineering | Year: 2014

The application of seismic protection devices such as dampers has fundamentally altered the landscape of earthquake engineering and design. Structures designed and built without such devices typically use a code-prescribed design that implies structural damage, loss of operation, and possible replacement at design-level events. By contrast, seismic design incorporating earthquake protection devices reduce demand on structural and nonstructural members. Viscous dampers are robust, cost-effective, and have a proven exceptional performance record in past earthquakes. For buildings with viscous dampers, the initial cost of their utilization is at least in part neutralized by reduction in cost of other structural members. The long-term performance is the key parameter used for evaluation. A code-based design structure, could require major repair or replacement after a design level earthquake. In contrast, structures properly designed with viscous dampers will likely only require minimum post-earthquake inspection and limited damage. An example design is presented as an illustration.


Miyamoto H.K.,Miyamoto International Inc. | Gilani A.S.J.,Miyamoto International Inc.
Structures Congress 2015 - Proceedings of the 2015 Structures Congress | Year: 2015

Performance based design with seismic protection devices such as viscous dampers have fundamentally altered the landscape of earthquake engineering and design. Structures designed and built without such devices typically use a code-prescribed design that implies extensive structural damage, loss of operation, and likely replacement at design-level earthquake. In contrast, performance based design incorporating earthquake protection devices leads to a combination of best engineering practice and reducing life-cycle costs. These devices are robust, cost-effective, and have a proven exceptional performance record in past earthquakes. In most cases, initial cost of their utilization is neutralized by reduction in cost of other structural members. The long-term performance is the key parameter used for evaluation. Structures properly designed with these devices will likely only require minimum post-earthquake inspection and can be fully operational within hours of a seismic event. When utilized for critical structures, such performance reduces the need for use of natural resources by eliminating post earthquake repair or reconstruction and thus improving the community resiliency. Example cases are presented.

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