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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. Source

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. Source

Gilani A.S.J.,Miyamoto International Inc. | Gilani A.S.J.,University of California at Berkeley | Takhirov S.,University of California at Berkeley
Ingegneria Sismica | Year: 2011

Suspended ceilings are among the most widely used nonstructural components. Past earthquakes have demonstrated the susceptibility of suspended ceilings to failure during seismic events. To address this vulnerability, design codes have incorporated specific design and installation criteria for suspended ceilings. However, ceiling and grid manufacturers continue to innovate and introduce new products that are requested by engineers and architects but are not addressed in the code. Therefore, it is necessary to have the means to evaluate such products. Because these units are difficult to analyze numerically, earthquake simulation testing can be used to assess the seismic performance of suspended ceilings. Such technique was used by one of the major manufacturers in the United States to characterize the performance of a standard code-prescribed ceiling and to use that performance as a benchmark for assessing the response of this manufacturer's alternate installation. Testing and evaluation of data showed that the code-prescribed installation had an acceptable performance. It was also noted that the ceiling constructed with the proposed alternate installation performed as well as or better than the specimen installed using the code procedure. Finally, the test data revealed some of the shortcomings of the current experimental and evaluation methodology that require revisions. Source

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. Source

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. Source

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