Bhutta M.A.R.,University of Technology Malaysia |
Maruya T.,Taisei Corporation |
Tsuruta K.,Research and Development Center
Construction and Building Materials | Year: 2013
Chloride diffusion is one of the main factors that affect concrete durability in harsh Arabian Gulf environment. This happens due to severe ground and ambient salinity and large fluctuations in temperature and humidity regimes and shortening the life span of the concrete structures. To study the performance of polymer-impregnated concrete permanent form (PICPF) to prevent chloride penetration, polymer-impregnated concrete panels (450 × 900 × 25 mm) were prepared as permanent forms for large-scale retaining reversible T-shaped reinforced concrete walls (Standard concrete wall and concrete wall covered with PICPF) and exposed to extremely aggressive environment site of the port city, Al Jubail, Saudi Arabia for more than 10 years. The foundation and lower half part of concrete walls were embedded into ground near the sea. This study focused on the use of PICPF in marine environment to prevent chloride ions penetration from atmosphere, ground and sea. The performance of PICPF to protect large-scale concrete walls from chloride attack from ground, atmosphere and sea was evaluated; core specimens were taken from concrete walls after 1.5-year, 5.4-year and 10.6-year outdoor exposure, and tested for carbonation depth, chloride ions penetration depth, and compressive strength. It was found that covering all surfaces of concrete walls with PICPF proved to be much effective in controlling water evaporation from concrete walls to atmosphere and to protect chloride attack from atmosphere, underground water and sea. © 2013 Elsevier Ltd. All rights reserved.
Baroghel-Bouny V.,University Paris Est Creteil |
Kinomura K.,University Paris Est Creteil |
Kinomura K.,Taisei Corporation |
Thiery M.,University Paris Est Creteil |
Moscardelli S.,Laboratoire Regional Des Ponts Et Chaussees Of Lest Parisien
Cement and Concrete Composites | Year: 2011
This paper investigates whether durability indicators (DIs), more specifically transport properties, can be assessed by simple methods, e.g. direct experimental methods or indirect methods based on analytical formulas, for every type of concrete. First the results of electrical resistivity and apparent chloride diffusion coefficient obtained by direct measurement on a broad range of materials, particularly on high-volume supplementary cementitious materials (SCM) mixtures, are discussed. Then, various methods, in particular methods based on these last parameters, are compared for the assessment of effective chloride diffusion coefficient and "intrinsic" liquid water permeability, including for the latter a sophisticated method based on numerical inverse analysis. The good agreement observed between the various methods points out that simple methods can allow DI assessment with sufficient accuracy. Moreover, the available values of electrical resistivity, effective/apparent chloride diffusion coefficients and "intrinsic" liquid water permeability can be included in a database. Throughout the paper, the specificities of high-volume SCM mixtures are highlighted. © 2011 Elsevier Ltd. All rights reserved.
Sanada H.,Japan Atomic Energy Agency |
Sugita Y.,Japan Atomic Energy Agency |
Kashiwai Y.,Taisei Corporation
International Journal of Rock Mechanics and Mining Sciences | Year: 2012
We have developed a multi-interval displacement sensor using Fiber Bragg Grating (FBG) technology, which has potential for the long-term durability, high accuracy and ability to transmit data over long distances. Field trials in the Horonobe Underground Research Laboratory (URL) of the multi-interval displacement sensor developed using FBG technology are described. Laboratory tests were carried out to obtain the relational expression computed from the interrelationship of the variation in the Bragg wavelength, temperature and displacement. From the results of laboratory tests, accuracy of the sensor was evaluated to be better than ±0.5% of the measurement range. In situ monitoring at the Horonobe URL using the developed sensor was carried out in parallel with nearby monitoring using a conventional extensometer, which is an electrical signal system type, for verification of the developed sensor. The results of the in situ test indicate that the displacement values from both the sensor developed and the conventional extensometer are almost equivalent. One of the advantages of the developed sensor is the absence of noise in the monitoring data, in contrast to the data from a conventional extensometer. © 2012 Elsevier Ltd.
Anderson J.G.,University of Nevada, Reno |
Uchiyama Y.,Taisei Corporation
Bulletin of the Seismological Society of America | Year: 2011
Path effects that are unique to the source-site geometry increase the uncertainties in ground-motion prediction equations (GMPEs). A methodology is proposed to deal with this issue. First a GMPE is developed, including site and event terms. A map of the logarithmic residuals may show that there are regions in which the spatial average is different from zero. The smoothed residuals become an additional correction to the GMPE. In principle, the contour maps of these corrections are unique to each strong-motion station, but maps of nearby stations should be correlated. The potential for path corrections to significantly improve ground-motion prediction at individual stations is tested first in a simplified pilot application on a small subset of Japanese peak-acceleration and peak-velocity data. For these data, the standard deviations to GMPEs without station or path corrections are in the range of 0.76 to 0.85 (in natural-log units). With the corrections the standard deviations are reduced to a range from 0.25 to 0.35. The method is also applied more strictly to the prediction of peak acceleration and peak velocity in Guerrero, Mexico. The result is reduction of the estimated standard deviation from 0.70 to 0.35 for peak acceleration and fro m 0.64 to 0.40 for peak velocity. After accounting for the path terms, the standard deviation at individual stations (single-station sigma) is estimated to be 0.51 and 0.48 for peak acceleration and peak velocity, respectively. This approach may be particularly appropriate for the design of critical structures with long lead times in their planning and design. If broadband and strong-motion stations are installed at the intended site immediately after site selection, site-specific corrections determined from background seismicity during the design stages can be used to refine and defend the design during the approval process.
Matsuhisa T.,Taisei Corporation
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2016
This paper starts epistemic approaches of studying the Bayesian routing problem in the frame work of the network game introduced by Koutsoupias and Papadimitriou [LNCS 1563, pp.404–413. Springer (1999)]. It highlights the role of common-knowledge on the users’ individual conjectures on the others’ selections of channels in the network game. Especially two notions of equilibria are presented in the Bayesian extension of the network game; expected delay equilibrium and rational expectations equilibrium, such as each user minimizes own expectations of delay and social cost respectively. We show that the equilibria have the properties: If all users commonly know them, then the former equilibrium yields a Nash equilibrium in the based KP-model and the latter equilibrium yields a Nash equilibrium for social cost in the network game. © Springer-Verlag Berlin Heidelberg 2016.