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In March 2011, the Tohoku tsunami swept over the east coast of Japan killing more than 15,000 people and missing more than 2,500 people. The tsunami resulted in collapsing of more than 400,000 buildings and washing away of more than 250 coastal bridges. In this study, the collapse of Tsuyagawa bridge damaged by the Tohoku tsunami is numerically investigated using the applied element method (AEM) because of its advantages for simulating structural progressive collapse. The AEM is a discrete crack approach that allows the elements separation, fall, and collision with each other in a fully nonlinear dynamic scheme of computations. The analysis was demonstrated to efficiently simulate the bridge collapse, showing that the bridge collapsed at a water speed of 6.6 m=s initiated by flexural failure of its piers. The study of bridge strengthening showed that the collapse water speed could be increased by 22 and 29% compared to Tohoku tsunami if piers are strengthened by a 100-mm RC jacket and 20-mm thick steel jacket, respectively. [ABSTRACT FROM AUTHOR]

Abstract: This paper aims to determine the mechanical behaviour of steel corrosion, which can be introduced into a concrete cracking model because of steel corrosion. Cyclic low-compression tests and oedometer tests were performed to analyse corrosion products collected from a reinforced concrete port that had been used for 40years in Japan. The results showed that steel corrosion is not a linear elastic material and the influence of Poisson’s ratio on the rust modulus is not significant. This study also found a value of 165MPa to specifically describe the apparent modulus of the rust. [Copyright &y& Elsevier]

In indoor environments with high levels of air pollution, it is desirable to remove major sources of emissions to improve air quality. In order to identify the emission sources that contribute most to the concentrations of indoor air pollutants, we used passive flux samplers (PFSs) to measure emission rates of carbonyl compounds and volatile organic compounds (VOCs) from many of the building materials and furnishings present in a room in a reinforced concrete building in Tokyo, Japan. The emission flux of formaldehyde from a desk was high (125μg/m2/h), whereas fluxes from a door and flooring were low (21.5 and 16.5μg/m2/h, respectively). The emission fluxes of toluene from the ceiling and the carpet were high (80.0 and 72.3μg/m2/h, respectively), whereas that from the flooring was low (9.09μg/m2/h). The indoor and outdoor concentrations of formaldehyde were 61.5 and 8.64μg/m3, respectively, and those of toluene were 43.2 and 17.5μg/m3, respectively. The air exchange rate of the room as measured by the perfluorocarbon tracer (PFT) method was 1.84/h. Taking into consideration the area of the emission sources, the carpet, ceiling, and walls were identified as the principal emission sources, contributing 24%, 20%, and 22% of the formaldehyde, respectively, and 22%, 27%, and 14% of the toluene, respectively, assuming that the emission rate from every major emission sources could be measured. In contrast, the door, the flooring, and the desk contributed little to the indoor levels of formaldehyde (1.0%, 0.54%, and 4.1%, respectively) and toluene (2.2%, 0.31%, and 0.85%, respectively). [Copyright &y& Elsevier]