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Six full-scale specimens were tested to examine the cyclic-loading performance of steel moment connections between an I-section beam and I-section column. The specimens represented the current practice in Japan in materials, dimensions, detailing, and fabrication. Three of the specimens had the beam welded to the web of the column; the other three had the beam welded to the flange of the column. Some of the specimens had doubler plates welded to the column web. Regardless of the framing orientation, the specimens displayed similar strength and stiffness. All specimens met the performance requirement for special moment frames according to US seismic provisions except for one specimen, which had the beam welded to the column web, and which failed prematurely by fracture of the continuity plate. Yielding of the continuity plate was found to be an important factor that can lead to such failure. Therefore, by making the continuity plates stronger than the beam flanges, either by adopting a sufficiently strong steel or thicker plate, moment connections to the column web, fabricated according to the current Japanese practice, may behave very similarly to moment connections to the column flange. [ABSTRACT FROM AUTHOR]

In this paper, fire safety engineering principles were applied to a steel-framed office building. The case study consisted of a 15-storey steel moment-resisting frame designed in Japan. Once the performance criteria had been defined, two severe fire scenarios for the unprotected structure, implying a different degree of building collapse, were identified and modelled in zone models, OZone and consolidated fire and smoke transport (CFast), as well as in the computational fluid dynamics software Fire Dynamics Simulator (FDS). Based on the results of the fire development simulation, several finite-element thermo-mechanical analyses were performed with SAFIR. OZone and CFast models, which are much less computationally demanding, provided comparable failure mode and time with respect to FDS. Since the steel frame was seismically designed as a moment-resisting frame in the two main horizontal building directions, the columns were particularly stocky. Moreover, they were only partially heated because they were located on the compartment edges. For these reasons, columns did not exhibit failure, in contrast to the assumptions taken in the risk-ranking process in relation to the evaluation of the consequences, suggesting a revision of such estimations and a possible iterative procedure for the definition of critical fire scenarios for the structure. [ABSTRACT FROM AUTHOR]

Due to their excellent biaxial bending strength, box columns are widely employed in countries with high seismic risk such as Iran and Japan. Although extensive research into the moment connections between I-beams and wide-flange columns has been conducted, a review of the literature indicated that studies on I-beam to box column moment connections are insufficient. To fill this gap, the cyclic behaviour of a two-sided moment connection of an I-beam to built-up box column was studied in this work. Non-linear finite-element models of the connection were developed and validated using test results available in the literature. In the studied connection, the beam flanges are joined to the column flange through flange plates. To reinforce the connection, vertical top and bottom rib plates were welded to the column flange and the flange plates. A parametric study was carried out to investigate the influences of the geometry of the rib plates on the behaviour of the connection. The results indicated that rib plates decrease the stress on the groove weld between the flange plates and the column flange and have insignificant influences on the global responses of the connection. [ABSTRACT FROM AUTHOR]

Over the course of the past 150 years, since the first iron- and steel-based bridge was constructed in 1868, Japan has become one of the most advanced countries in the construction of steel structures. Various innovative and elegant steel structures were constructed in the past such as the world's longest suspension bridge called the Akashi Kaikyo Bridge. The advances of steel structures were attributed to a significant extent to the development of high-performance steels. Such materials developed in Japan were characterized by three types of versatilities: strength, functional, and sectional. Some examples of such materials include fairly high and low strength steels, high-bridge performance steel, seismic-resistant steel, fire-resistant steel, and size-flexible H-shaped beam. In Japan, these steel material innovations enabled the progress in steel structures to leap forward and in turn challenging new structures gave birth to further advancements in steel materials. In this paper, the advancements of steel structures and materials were reviewed, focusing largely on the steel materials and their contributions to the construction of steel structures. In addition, in light of recently developed innovative steels and their strength-increasing potential, the further advancements of steel materials were suggested for the future innovations of steel structures. [ABSTRACT FROM AUTHOR]