Document Details

OPERATION HARDTACK-PROJECT 3.2: RESPONSE OF EARTH-CONFINED FLEXIBLE ARCH STRUCTURES IN HIGH-OVERPRESSURE REGIONS (DELETED)

LEDOUX, J C [NAVAL CIVIL ENGINEERING LABORATORY, FT. HUANEMA, CA]; RUSH, P J [NAVAL CIVIL ENGINEERING LABORATORY, FT. HUANEMA, CA]

HARDTACK I OPERATION; BLAST EFFECTS; DAMAGE; RESEARCH PROGRAMS; KOA EVENT

Location - DOE/NNSA NUCLEAR TESTING ARCHIVE Address - P.O. Box 98521 City - Las Vegas State - NV Zip - 89193-8521 Phone - (702)794-5106 Fax - (702)862-4240 Email - NTA@NV.DOE.GOV

REPORT

1962 Jan 22

Sanitized

0158

NV0051056

WT1626EX

NAVAL CIVIL ENGINEERING LABORATORY, FT. HUANEMA, C

1994 Aug 26

2003 Sep 18

FOUR PREFABRICATED CORRUGATED STEEL FLEXIBLE ARCH STRUCTURES, CONFINED WITHIN NON-DRAG-SENSITIVE EARTHWORK CONFIGURATIONS OF CORAL SAND, WER E TESTED TO DETERMINE THE RESPONSES AND FAILURE CRITERIA OF SUCH STRUC TURES. THE RESPONSES OF THE EARTH-CONFINED FLEXIBLE ARCH STRUCTURES W ERE DEDUCED FROM POSTSHOT EXAMINATIONS OF THE STRUCTURES AND FROM STUD IES OF THE RECORDS OF LOADINGS, ACCELERATIONS, AND DEFLECTIONS AS RELA TED TO TIME. IN THE AREA OF SHOT CACTUS, A SURFACE DETONATION OF ABOU T 18 KT, RECOVERY OF RECORDS AND EXCAVATIONS FOR STRUCTURAL EXAMINATIO NS FOR STRUCTURAL EXAMINATIONS WERE COMPLETED WITHIN 8 DAYS OF THE EVE NT. HERE, STRUCTURE 3.2A-A 10-GAGE CORRUGATED STEEL, FLEXIBLE ARCH WI TH A 25-FOOT SPAN AND A 48-FOOT LENGTH, CONFINED WITHIN A MASSIVE EART HWORK-WAS SUBJECTED TO [ ] PEAK OVERPRESSURE OF RELATIVELY SHORT D URATION. THIS STRUCTURE SUSTAINED PARTIAL COLLAPSE ON THE SIDE AWAY F ROM GROUND ZERO. THE COLLAPSE APPARENTLY BEGAN WITH BEARING FAILURE O F THE SHELL PLATES AT A HORIZONTAL BOLTED SEAM, APPROXIMATELY 5 FEET A BOVE FLOOR LEVEL ON THE COLLAPSED SIDE OF THE STRUCTURE. IN THE AREA OF SHOT KOA, A 1.31-MT SURFACE DETONATION, FIRST RECONNAISSANCE EFFORT S AND RECOVERY OF A FEW RECORDS WERE ACCOMPLISHED 4 DAYS AFTER THE EVE NT, BUT THE IMMINENCE OF SUCCEEDING DETONATIONS IN THE AREA AND THE HA ZARDS OF RADIOLOGICAL CONTAMINATION DELAYED EXTENSIVE RECOVERY OPERATI ONS UNTIL 170 DAYS AFTER THE EVENT. SOME OF THE INSTRUMENTS AND RECOR DS WERE DAMAGED EITHER BY THE BLAST OR BY THE EXPOSURE TO THE ENVIRONM ENT. IN THE RELATIVELY LONG DURATION BLAST LOADING CREATED BY SHOT KO A, STRUCTURE 3.2B WAS IN THE [ ] OVERPRESSURE REGION AND STRUC TURE 3.2C WAS IN THE [ ] REGION. THESE STRUCTURES HAD THE SAME DIMENSIONS AND DESIGN AS STRUCTURE 3.2 MENTIONED ABOVE, AND THEY, TOO, WERE CONFINED WITHIN MASSIVE EARTHWORDS. BOTH STRUCTURES HAD COLLAPS ED SYMMETRICALLY ABOUT THE CROWN, FAILED AT HORIZONTAL BOLTED SEAMS 5 FEET ABOVE FLOOR LEVEL, FAILED AT CERTAIN TRANSVERSE SEAMS, AND SUFFER ED SEVERE DAMAGE AND DISPLACEMENTS OF CONCRETE FOUNDATION FOOTINGS. I N THE SAME BLAST LOADINGS BY SHOT KOA, STRUCTURE 3.2D WAS IN THE [ ] OVERPRESSURE REGION. THIS STRUCTURE WAS A 1-GAGE CORRUGATED STEE L, FLEIBLE ARCH WITH A 38-FOOT SPAN AND A 40-FOOT LENGTH, WITHIN A MAS SIVE EARTHWORK. IT HAD FIRST BEEN DEFORMED IN THE COMPRESSION BENDING MODE, THEN BEEN FURTHER DISPLACED DOWNWARD AT THE CROWN, BEEN SUBJECT ED TO A LARGE INFILTRATION OF SAND THROUGH THE FAILURE OF NONSTRUCTURA L ENDWALLS, SUFFERED SEVERE DAMAGE AND DISPLACEMENTS TO CONCRETE FOUND ATION FOOTINGS, AND REACHED A FINAL SEVERELY DEFORMED PEAKED SHAPE WIT H SYMMETRICAL REVERSAL OF CURVATURES OF THE ARCH ON BOTH SIDES OF THE CROWN.