December 2007 Chile Observatories Earthquake Preparedness Workshop 1 Chile Observatories Earthquake Preparedness Workshop Atacama Large Millimeter/submillimeter Array ALMA Eduardo Donoso
Dec 26, 2015
December 2007 Chile Observatories Earthquake Preparedness Workshop 1
Chile Observatories Earthquake Preparedness Workshop
Atacama Large Millimeter/submillimeter Array
ALMA
Eduardo Donoso
December 2007 Chile Observatories Earthquake Preparedness Workshop 2
Table of Contents
• Present status of ALMA Construction
• Seismic Requirements– Buildings– Antenna foundations– Computers – Instruments racks
• November 14, 2007 Earthquake
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San Pedro de Atacama,Atacama Desert, Northern ChileOSF SiteAOS
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AOS (43km)
OSF Site (15km)
ALMA Sites
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AEM Contractor AreaAEM Contractor Area
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MELCO Contractor AreaMELCO Contractor Area
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Center of Array
Pampa La BolaV. Licancabur Cº Chajnantor
Chajnantor Plateau – looking north
AOS Technical Building
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AOS Technical Building
AOS Technical Building
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27 Mar 2007 Full configuration - 192 pads
7446000
7448000
7450000
7452000
7454000
7456000
7458000
7460000
7462000
7464000
618000 620000 622000 624000 626000 628000 630000 632000 634000 636000
UTM-X
UT
M-Y
Central+Inner ArrayY WestACAY SouthY Pampa La Bola
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ALMA + ACA Atacama Large Millimeter/submillimeter Array
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Seismic requirements
Temporary Buildings• Chilean Code
Permanent Buildings
• ALMA special requirements – more stringent: 0.28 g• Chilean Code requirements – 0.20 g• No structural damage design
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No structural damage design
• Extremely conservative design: 0.446 g vs 0.28 g– Code written to minimize structural damage and prevent collapse:
• Structure yields• Personnel evacuation• Costly repairs – 5.000 m = $$$
– ALMA designs to minimize damage (loads 5 times higher than required by code):
• Seismic response factor 1 – no damping; accel. assumed directly to structure
• No yield• No evacuation• No damage• Construction cost higher, but no operation stop
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Permanent Buildings Special Features
Rock anchors
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Seismic requirements
Antenna foundations
• Case 1: Embedded into rock• Case 2: Rock anchors – foundation laying on rock• Case 3: Massive concrete standalone
– In all cases stiffness governs design – operational requirement of high weight and fast switching
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Seismic requirements
Computers – Instruments
• Seismic design anchoring to foundations
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Effects
November 14, 2007 Earthquake
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Nothing happened
• No photos – no damage - ☺
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www.alma.info
The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership among Europe, Japan and North America, in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere, in Japan by the National Institutes of Natural Sciences (NINS) in cooperation with the Academia Sinica in Taiwan and in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC). ALMA construction and operations are led on behalf of Europe by ESO, on behalf of Japan by the National Astronomical Observatory of Japan (NAOJ) and on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI).