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Sato H.,Nippon Steel and Sumikin Engineering Co. | Yamaji T.,Port and Airport Research Institute | Sakai J.,Waseda University
Zairyo to Kankyo/ Corrosion Engineering | Year: 2015

To evaluate the corrosion risk of offshore steel structures at submerged zone caused by stainless steel sheathing and cathodic protection failures, it is essential to grasp the degree of the carbon steel-stainless steel galvanic corrosion. The objective in this study was to clarify the effect of area ratio of stainless steel coupled to carbon steel on corrosion behavior in sea water. As a result, stainless steels promote galvanic corrosion, but the degree of accelerated corrosion was much smaller than that estimated from the area ratio. Calcareous deposits had formed on the surface of stainless steels during galvanic tests in seawater. The calcareous deposits appeared to diminish the diffusion of the dissolved oxygen and diminish the cathodic reaction of oxygen reduction on the stainless steel surface. Source

Hikino T.,Nippon Steel and Sumikin Engineering Co. | Okazaki T.,Hokkaido University | Kajiwara K.,Hyogo Earthquake Engineering Research Center | Nakashima M.,Kyoto University
Journal of Structural Engineering (United States) | Year: 2013

Abstract Large-scale shake table tests were performed at E-Defense to examine the out-of-plane stability of buckling-restrained braces (BRBs). Two specimens were subjected repeatedly to a near-fault ground motion with increasing amplification. The test specimens comprised a single-bay, single-story steel frame and a pair of BRBs placed in a chevron arrangement. The specimens were not braced at the brace-to-beam intersection in order to produce a condition where the BRBs were susceptible to out-of-plane instability. Standard BRBs were used in the first specimen, while BRBs with a flexible segment at each end of the steel core were used in the second specimen. A simple stability model predicted the BRBs in the second specimen to fail because of out-of-plane buckling. The first specimen exhibited excellent ductility during the shake table tests, while the second specimen developed severe out-of-plane deformation that compromised the ductility of the BRBs. Based on the experimental observations and the stability model, a methodology is proposed to evaluate bracing requirements at the brace-to-beam intersection. © 2013 American Society of Civil Engineers. Source

Jiao Y.,Tokyo University of Science | Konishi Y.,Nippon Steel and Sumikin Engineering Co. | Hoashi Y.,Nippon Steel and Sumikin Engineering Co.
Journal of Structural and Construction Engineering | Year: 2016

Current design practices for base-isolated structures in Japan typically involve conducting time-history analysis using a single seismic component. However - in reality - the isolation system has a bidirectional response which means that the damage of seismic isolation devices may be underestimated during design procedure. This is particularly true for the object of the present study - U-shaped steel dampers -, which were proved to have a reduced ultimate deformation capacity under bidirectional loading. The present study conducts a quantitative comparison between the results obtained using: (1) a 1D model (SDOF system with single component of the ground motion), and (2) a 2D model (MSS with 2DOFs and both components of the ground motion). Different seismic design levels were investigated and several formulae for predicting the bidirectional damage using indicators based on one-directional analysis were proposed. Source

Hayashi M.,Nippon Steel and Sumikin Engineering Co. | Mimura T.,Nippon Steel and Sumikin Engineering Co.
Energy Procedia | Year: 2013

The most efficient energy cut-off chemical absorption process has been developed in the project of COURSE50 (CO2 Ultimate Reduction in Steelmaking process by innovative technology for cool Earth 50). Through each long hours running by the use of several kinds of newly developed absorbents, high energy saving, utilization of far lower temperature , and extremely low influence of the process to steel making facilities downstream of the process have been tested and verified using of actual blast furnace gas in the steel works. © 2013 The Author. Source

Wada M.,Nippon Steel and Sumikin Engineering Co. | Tokimatsu K.,Tokyo Institute of Technology | Sawaishi M.,Nippon Steel and Sumikin Engineering Co.
Journal of Structural and Construction Engineering | Year: 2016

In order to estimate the effects of cyclic loading on bearing capacity and pull-out resistance of piles, monotonic and cyclic vertical loading tests were conducted on a pile with or without spiral wings in uniformly graded sand in a calibration chamber. Both pushing and pulling shaft friction decreased with increasing the cyclic loading force, whereas the pushing end wing and tip resistance did not decrease with increasing the cyclic loading force. Source

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