CHAPTER 2 DAMAGE SURVEY AND ANALYSIS OF STRUCTURE 3.1.) 2.1 GENERAL Structure 3.1.1, the Greenouse Army Test Building, was the only structure examined at the site of Operation Ivy which had Leen constructed for the exclusive purpose of measuring the effect cf air blast from nuclear weapons on surface structures. This structure hapr aed to be located at a rangs from Ground Zero of shot Mike® of Operation Ivy such that the damege caused by the air blast wag witsis iimits suitable for a dynamic analysis. In addition, complete plang were availaole for ‘'e structure, and damage survey notes were availabie for the previous nuctear shots which had damaged the structure. The magnitude of tne air-blast wave for shot Mike of Operation Ivy at the location of Structure 3.1.1 was not known rellably, although a number of measurements cf air-blast overpressures were made at various disiances {rom Ground Zero.’ Therefore an estimateof the actual air-blast pressure at Structure $.1.1 can best be <btained by aynamic analyses of Buildings 2 and 3 of this at.ucture. Various levels of air-biast overpressure are assumed, and the response is computed using methods of analysis which have been developed.'3-' A comparison of the computed response for the various asau.ned leve._ of :.iz-Llast overpressure with the actual values of permanent deflection measured in the fiela survey !24ds to an estimate of the proucble atr-blast overpressure at the locaticn of Siructure 3.1.1. The field survey measurements and photographa of Structure 3.1.1 are presented in Sec. 2.2. The ¢ynamic analyses of Srildings 2 and 3 are presented in Sec 2.2. 15 SECRET~ RESTRICTED DATA my aoe *Shot King ofOverction Ivy produced air blast overpressurea at Structure 3.1.1 of sucha low magnitude thet no measurable damage occurred from this shot. d rabies: Whean Sove wos Mdichaneta F or T made by a representative of the Office of t1.o Chief of Engineera in the fall of 1952. A description of the post-lvy damage survey and resulta is presented in the following sections. i Sh iad oe obtained foiiowing shota Easy and Item of Operation Greenhouse’ard com the pretest visit lneciae ke Lie aba bie cal She ee ea a) te ky The image survey measurements made afie, Operation Ivy consisted in exterior-walloffset measurements, colums-<ffsct nwasurementa, and icof-elevation measurement. In addition, general cbservatious ani photographs were made of the utructure which :. shown diagrammatically in Fig. 2.1, Since no bench marks or fixed soints were available upon which to base the measurements, only relat! e horizontal and vertical displacements of the structure were obtainec. The pre-Ivy condition of Structure 3.1.1 was determined {rom survey notes and phtugrachs TT SURVEY MEASUREMENTS AND RESULTS i 2.2