Papers - KAWANA Futoshi
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COMPRESSIVE STRAIN ESTIMATION METHOD OF GRANULAR BASE OF ASPHALT PAVEMENT USING FWD DEFLECTION CURVETURE Reviewed
TAKEUCHI Yasushi, YAMAMOTO Naoki, KAWANA Futoshi, YABU Masayuki, WATANABE Kazuhiro
Infrastructure Maintenance Practices 3 ( 1 ) 40 - 47 2024
Language：Japanese Publishing type：Research paper (conference, symposium, etc.) Publisher：Japan Society of Civil Engineers
<p> In this study, as a method for evaluating the soundness of the granular base directly from the FWD deflection shape, we focused on the granular base compressive strain prediction equation shown in the NCHRP report. Then, the accuracy of the NCHRP’s prediction formula was using the FWD survey results on the national highway was verified, and based on the FWD operating conditions in Japan, a new prediction equation establish method was examined. As a result, it was found that the prediction equation of NCHRP tends to deviate from analytical results of FWD using the multilayered elasticity theory (MLET). In addition, the MLET analysis results based on the FWD operating conditions in Japan were used to formulate the compressive strain prediction equation and the temperature correction equation, and the threshold for the compressive strain soundness evaluation was shown.</p>
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Evaluation of the Effect of Interlayer Bonding Condition on the Deterioration of Asphalt Pavement Reviewed
Wakabayashi Yuya, Takeuchi Yasushi, Kawana Futoshi, Watanabe Kazuhiro
Transportation Research Record: Journal of the Transportation Research Board 2677 ( 7 ) 500 - 508 2023.02
Language：English Publishing type：Research paper (international conference proceedings) Publisher：SAGE Publications
<jats:p> In this study, to investigate the effect of interlayer bonding condition on the deterioration of asphalt pavement, we conducted numerical analysis based on multi-layer elastic theory, verification of numerical analysis results by experiments on a full-scale test track, and comparison of the progress of deterioration based on accelerated loading tests conducted on the test pavement. Firstly, the analysis indicated that stronger tensile strain could occur on the upper side of the interlayer when the interlayer bonding weakens. Furthermore, the test pavement simulating interlayer debonding showed the same strain tendency as the analysis. These results suggest that if the interlayer debonding continues, the pavement may suffer early fatigue failure. On the other hand, there are some results that are not consistent with those of the analysis, such as the magnitude of deflection in the test pavement; thus, further investigation is required. Furthermore, because of the accelerated loading on the test pavement, the sections where the layers were debonded immediately after construction became bonded. Since the deflection of the test pavement did not change significantly from that immediately after construction, and no conspicuous damage such as cracks was observed on the road surface, it is considered necessary to continue follow-up surveys. </jats:p>
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KAWANA Futoshi, KOUNO Asako, TAKEUCHI Yasushi
Journal of Japan Society of Civil Engineers, Ser. E1 (Pavement Engineering) 78 ( 2 ) I_100 - I_108 2023
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Civil Engineers
<p> In this study, to evaluate the influence of variability of the design variable on calculated strain for asphalt pavement, Monte Carlo simulation was demonstrated. The results are summarized as follows. (1) The design parameters having the greatest influence on the horizontal strain variability at the bottom of the asphalt layer are asphalt elastic modulus, base elastic modulus and asphalt thickness. (2) The design parameters having the greatest influence on the vertical strain variability at the top of the subgrade are layer thickness, subgrade elastic modulus and subgrade Poisson’s ratio. (3) In the case of thick asphalt layer, it was confirmed that the coefficient of variation of the strain became the constant value without depending on pavement structure and elastic modulus if coefficient of variation of each design variable was given. (4) On the other hand, when thickness of asphalt layer was thin, coefficient of variation of the strain greatly changed depending on pavement structure and elastic modulus.</p>
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STUDY ON ESTIMATION METHOD OF RESILIENT MODULUS MATERIAL CONSTANTS OF SUBGRADE USING PORTABLE FWD Reviewed
TAKEUCHI Yasushi, KAWANA Futoshi, YAMANAKA Koichi, KOHATA Yukihiro, SEKINE Etsuo
Journal of Japan Society of Civil Engineers, Ser. E1 (Pavement Engineering) 78 ( 1 ) 40 - 51 2022
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Civil Engineers
<p> In this study, in order to measure quickly the results equivalent to the <i>M<b>r</b></i> test in the field and to enable appropriate bearing capacity evaluation of subgrade in the theoretical structural design of pavement, estimation method of material parameters used for <i>M<b>r</b></i> calculation from portable FWD test results using the multilayered theory was examined. As a result, it was found that the calculation point can be set from the forward analysis using the multilayered elastic theory, and that the material parameters can be obtained using regression equation of <i>M<b>r</b></i> from the stress state at the calculation point. In addition, by analyzing past <i>M<b>r</b></i> test results, it was found that the depth of the calculation point and the elastic modulus of the subgrade can be approximated by the linear equation.</p>
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路床のレジリエントモデュラスを用いた小型FWD試験の順解析 Reviewed
山中光一，竹内康，川名太，峯岸邦夫
土木学会論文集E1（舗装工学） 77 ( 2 ) I_225 - I_231 2021
Language：Japanese Publishing type：Research paper (scientific journal)
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アスファルト舗装の層間はく離が内部応力やたわみに及ぼす力学的影響に関する検討 Reviewed
若林由弥，川名太，渡邉一弘
土木学会論文集E1（舗装工学） 76 ( 2 ) I_115 - I_122 2020
Authorship：Corresponding author Language：Japanese Publishing type：Research paper (scientific journal)
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APPLICATION OF VEHICLE WEIGHT INVETIGATIONS TO CONCRETE PAVEMENT SLAB THICKNESS DESIGN
TAKEUCHI Yasushi, NISHIZAWA Tatsuo, KAWANA Futoshi, KUWABARA Masaaki, KOYANAGAWA Masashi
Journal of Japan Society of Civil Engineers, Ser. E1 (Pavement Engineering) 76 ( 2 ) I_21 - I_28 2020
Language：Japanese Publisher：Japan Society of Civil Engineers
<p> In this study, in order to apply the vehicle weight investigation results conducted by the Ministry of Land, Infrastructure, Transport and Tourism to the concrete pavement slab thickness design, the temperature measurement results of the concrete slab measured at 9-locations in Japan were analyzed to determine the time zone when the thermal stress is positive or negative, and extract the wheel load group passing at that time zone. And the effects of these results on the concrete slab fatigue damage calculation were investigated. As a result, it was found that the data of the wheel load and its action frequency collected every 12 hours in the vehicle weight investigation correspond to the time zone when the thermal stress is positive or negative, and can be used directly for the concrete slab thickness design. On the other hand, it was found that the fatigue damage level of the concrete slab when using the track traffic per day was estimated excessively according to the current design method.</p>
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Strength Characteristics of Stabilized Soils Containing Bamboo Fiber Extracted by Steam Explosion Reviewed
FUTOSHI KAWANA
International Journal of Environmental and Rural Development Vol.9 ( 1 ) 156 - 161 2018.06
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)
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最大たわみを用いた動的逆解析 の舗装構造評価への適用性検討
川名太，渡邉真一，竹内康，松井邦人
土木学会論文集E1（舗装工学） 73 ( 3 ) I_19 - I_26 2017.12
Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal)
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遊具からの落下に対する安全性を考慮した歩行者系舗装の表層厚さの設計法の提案 Reviewed
青木政樹，竹内康，城本政一，川名太
土木学会論文集E1（舗装工学） 73 ( 3 ) I_45 - I_51 2017.12
Language：Japanese Publishing type：Research paper (scientific journal)
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Development of a Device for Measuring the Load Bearing Capacity of a Farm Road Reviewed
KOJI WATANABE, FUTOSHI KAWANA, YASUSHI TAKEUCHI
International Journal of Environmental and Rural Development Vol.8 ( 1 ) 49 - 55 2017.08
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)
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Numerical modelling of flexible pavement incorporating cross-anisotropic material properties, Part II:Surface rectangular loading Reviewed
JW Maina, F Kawana, K Matsui
Journal of the South Africa Institution of Civil Engineering 59 ( 1 ) 28 - 34 2017.04
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)
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Numerical modelling of flexible pavement incorporating cross-anisotropic material properties, Part I:Surface circular loading Reviewed
JW Maina, F Kawana, K Matsui
Journal of the South Africa Institution of Civil Engineering 59 ( 1 ) 22 - 27 2017.04
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)
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衝撃吸収性を考慮した歩行者系舗装の構造設計方法の適用性に関する実験的検証 Reviewed
青木雅樹，竹内康，城本政一，川名太
土木学会論文集E1（舗装工学） 72 ( 3 ) I_187 - I_193 2016.12
Language：Japanese Publishing type：Research paper (scientific journal)
層厚等の異なる26種類の試験舗装に対して路面弾性係数の評価を行い，室内試験で得られた結果と比較することで，衝撃吸収性を考慮した舗装厚設計法の適用性を確認にした．
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Effects of Surveying Methods between GNSS and Direct Leveling on Elevation Values over Long Distance in Mountainous Area Reviewed
TAKAHIKO KUBODERA, HIROMU OKAZAWA, YOSHIHARU HOSOKAWA, FUTOSHI KAWANA, EIJI MATSUO, MACHITO MIHARA
International Journal of Environmental and Rural Development 7 ( 1 ) 62 - 69 2016.06
Language：English Publishing type：Research paper (scientific journal)
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感圧紙を用いた小型FWDによる路盤の変形係数推定法に関する研究 Reviewed
上浦正樹，川名太，松井邦人
土木学会論文集E1（舗装工学） 71 ( 3 ) I_153 - I_160 2015.12
Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal)
小型FWD試験結果の動的逆解析によって，路盤や路床の変形係数を求める場合，接地圧分布を明らかにしておくことが望ましい．そのため，感圧紙を用いて接地圧分布を推定する方法を提案するとともに，一般的な非線形軸対称荷重を考慮できる動的逆解析プログラムを開発した．
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接地圧分布を考慮した動的逆解析の適用性に関する検討 Reviewed
川名太，中村博康，高橋茂樹，竹内康，松井邦人
土木学会論文集E1（舗装工学） 71 ( 3 ) I_145 - I_152 2015.12
Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal)
インバースパラボリック分布，パラボリック分布および等分布の接地圧分布が設定できる動的逆解析プログラムを開発し，載荷板の接地圧分布が動的逆解析の推定値に与える影響を評価した．
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小型FWD用接地圧測定装置による地盤の変形係数評価 Reviewed
上浦正樹，川名太，松井邦人
土木学会論文集E1（舗装工学） 70 ( 3 ) I_57 - I_64 2014.12
Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal)
小型FWD 試験のために試作した接地圧測定装置により粘土，砂，礫などの種類が異なる路盤で接地圧を測定し，接地圧分布の違いを明らかにし，この違いが動的逆解析で得られる変形係数に与える影響を検討した．
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信頼度に応じた路盤厚設計曲線を用いたコンクリート舗装の2層系路盤設計法の検討 Reviewed
竹内康，小梁川雅，川名太，西澤辰男，堀内智司
土木学会論文集E1（舗装工学） 70 ( 3 ) I_49 - I_55 2014.12
Language：Japanese Publishing type：Research paper (scientific journal)
信頼度の異なる路盤設計曲線を用いた場合の２層系路盤上での支持力をモンテカルロシミュレーションにより検討し，簡易な信頼度算出方法を提案した．
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Effects of loading duration on concrete pavement responses based on wave propagation theory Reviewed
Futoshi Kawana, Masashi Koyanagawa, Kunihito Matsui
8th International DUT-Workshop on Research and Innovations for Design of Sustainable and Durable Concrete Pavements 2014.09
Authorship：Lead author Language：English Publishing type：Research paper (international conference proceedings)
FWD試験で得られるたわみの最大値のみを用いて動的逆解析を行い，舗装の健全性を評価する方法を提案した．また，本手法を用いて，実際に供用されているホワイトトッピング舗装の健全度の評価を試みた．