Computer system and software data shall be provided in accordance with Attachment 1, A1.2.5.18 of this volume.
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| WESTERN RANGE SEISMIC DESIGN |
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The probability of the WR being exposed to a severe earthquake is great enough to require taking specific mitigating measures in design. This chapter identifies equipment seismic design requirements. Equipment includes aerospace ground equipment (AGE), ground support equipment (GSE), flight hardware integrated with GSE, and ground support systems (GSS). For simplification, the terms equipment and/or GSE are used in this chapter to include AGE, GSE, and GSS. Seismic requirements do not apply to the spacecraft itself, but do apply to spacecraft integrated with GSE. For example a spacecraft mounted on a support stand would be analyzed as a unit and protected accordingly.
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Applicability of Design and/or Anchorage or Restraint Requirements |
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17.1.1. Equipment needed/required for post-earthquake recovery, essential equipment (per code definition), or safety critical equipment, shall be designed to remain operational or revert to a “safe mode” during a seismic event, and to be operational immediately following a seismic event. This equipment shall be designed with an importance factor of 1.5 (I = 1.5). If the payload project, PSWG and Range Safety determine that the equipment is not essential to life safety, an importance factor of 1 may be used.
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17.1.2. Equipment whose failure or excessive deflections during a seismic event could propagate to a catastrophic event or endanger personnel, high-pressure systems, or systems used to store hazardous or toxic materials shall be designed and anchored to withstand a seismic event. The equipment need not remain operational after the seismic event as long as personnel safety is preserved.
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17.1.3. Equipment whose movement could propagate to a catastrophic event, block personnel egress avenues, or injure personnel shall be secured to prevent movement.
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17.1.4. Transportation equipment shall be stored with the casters or wheels locked or blocked. Transportation equipment shall be stored in open areas so that if movement occurs during an earthquake, the equipment shall not impact adjoining structures (for example, building columns) and propagate into a facility failure.
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17.1.5. Gravity friction shall not be used as the only means to anchor or restrain equipment.
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Basis for Design |
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17.2.1. Seismic design of equipment, supports and/or anchorages shall be in accordance with the International Building Code (IBC), American Society of Civil Engineers Minimum Design Loads for Buildings and Other Structures (ASCE/SEI 7-10), and the additional requirements specified in this publication.
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17.2.2. Local Geotechnical shall be used to determine site soil classification. Data may be available within 300 ft of the equipment or facility and can be used to determine the site soil classification. If a geotechnical report is too costly and not available, a site soil classification D shall be used if deemed appropriate by the payload project, PSWG and Range Safety.
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17.2.3. Appropriate seismic hazard mitigation shall be implemented for high cost computer or electronic equipment.
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Where it is cost-effective, high-cost computer or electronic equipment should be mounted on seismic isolation bearings to mitigate damage during an earthquake. FEMA 74, Reducing the Risks of Non-Structural Earthquake Damage, A Practical Guide, should be used as a guide to reduce the risk of earthquake non-structural damage.
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17.2.4. Seismic Loading and Loads Combinations
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17.2.4.1. Seismic loads for AGE/GSE shall be calculated in accordance with the IBC and ASCE/SEI 7-10.
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17.2.4.2. Seismic loading shall include vertical component in addition to the horizontal component to evaluate the total earthquake load. This is accomplished per ASCE/SEI 7-10 by multiplying 0.2 by the spectral response and the dead load (0.2*SDS*D).
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17.2.4.3. Calculation of the seismic loads shall consider dynamic amplification and the dynamic characteristics of the GSE and their supports and anchorage to ensure the proper seismic response factor is selected.
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17.2.4.5. Loads combinations shall be in accordance with IBC and ASCE/SEI 7-10, American Society of Civil Engineers Minimum Design Loads for Buildings and Other Structures.
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17.2.5. Exemptions. GSE that meets any of the following criteria shall be exempt from seismic design and/or restraint requirements:
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17.2.5.1. Internal operational elements of GSE that are confined within the GSE structure.
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17.2.5.2. Man-handled GSE physically attached to flight hardware or GSE.
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17.2.5.3. GSE categorized as hand tools.
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17.2.5.4. GSE temporarily positioned in support of operations, on a case-by-case basis, those items may be ruled exempt by the PSWG and Range Safety based on the results of a risk analysis. The analysis shall address risk for catastrophic failure of the equipment, or any potential catastrophic event the equipment may precipitate. These include, but are not limited to: excessive movement that may impact another hazardous system, movement that may block and egress routes, release of stored energy, or tipping that may present a crushing or pinching hazard.
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17.2.6. Existing Equipment. For programs and/or projects planning to reuse existing GSE that does not meet the requirements in this publication, payload project safety and engineering shall assess that equipment for potential risk. The payload project shall coordinate the risk assessment with the PSWG and Range Safety and formulate risk mitigation plans for the GSE in question.
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