Report - PEER - University of California, Berkeley

fabricate and load them in the laboratory, whereas miniature models are known to failto duplicate the prototype behavior because of lack of similitude. Considering thesecircumstances, the writers conducted an experimental project in which a full-scale,three-story steel building frame was loaded quasi-statically to failure. The primaryobjectives of the project were: (1) to acquire realistic data about performance,progress of damage, and final failure of the concerned frame in deformation rangesthat are far beyond those considered in contemporary seismic design; (2) to examinethe interaction between the local damage induced into individual members andelements and the global damage sustained by the structural frame; (3) to observeeffects of RC floor slabs on the behavior of steel moment frames; (4) to examine theinteraction between the structural system and exterior finishes; and (5) to calibrate thecapacity of numerical analyses to trace the behavior to collapse. This paper reportson the outline of the test and the results about the overall behavior, interactionbetween the structural frame and exterior finishes, and ability of a plastic-hinge basednonlinear analysis to trace the experimental cyclic behavior. Other issues of interest,i.e., interaction between the local damage and global behavior, effects of compositeaction, and behavior to final collapse are being explored, and preliminary findings arepresented elsewhere (Matsumiya et al. 2004a; Matsumiya et al 2004b).2. TEST STRUCTUREThe test structure was a three-story, two-bay by one-bay steel moment frame asshown in Fig.1, having a plan dimension of 12 m (in the longitudinal direction) by8.25 m (in the transverse direction). The structure was designed following the mostcommon design considerations exercised in Japan for post-Kobe steel momentframes. That is, the columns were made of cold-formed square-tubes, beams weremade of hot-rolled wide-flanges, the through-diaphragm connection details wereadopted, in which short brackets were shop-welded to the columns [Fig.2(a)]. Thecolumns with short brackets were transported to the test site, and they were connectedhorizontally to beams by high-strength bolts. Metal deck sheets were placed on top ofbeams, with studs welded to the beam top flanges through the metal deck sheets.Wire-meshes were placed above the metal deck sheets, and concrete was placed onsite. Fabrication and construction procedures adopted for the test structure faithfullyfollowed those exercised in real practice (Nakashima et al., 1998). Exception was thecolumn bases. Instead of embedding anchor bolts in the foundation RC beams,anchor bolts were fastened in short, deep steel beams, which in turn were securelytied down to the strong floor [Fig.2(b)].The two-planes placed in parallel in the longitudinal direction were nearlyidentical, but one plane, called the “South” plane, had a floor slab extended on theexterior side by 1.5 m, while the other plane, called the “North” plane, had a floorslab that terminated at the beam end (Fig.1). This overhang was designed to make itpossible to directly measure the effects of RC floor slabs from the difference inresistance between the two planes. The columns were extended to the approximate270