The Experts below are selected from a list of 17937 Experts worldwide ranked by ideXlab platform
Saiji Fukada - One of the best experts on this subject based on the ideXlab platform.
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Method for Construction, Maintenance, and Management of Rigid-Frame Bridges Using H-Shaped Steel Girders
International Journal of Civil Engineering, 2019Co-Authors: Yoshiaki Nakai, Mitsuhiko Tokuno, Saiji FukadaAbstract:This work outlines an actual case study performed on a Rigid-Frame bridge using H-shaped steel girders in the laboratory and introduces the process of construction, maintenance, and management of the proposed bridge structure in practical cases. A novel structural Rigid connection was developed for H-shaped steel girders and reinforcing bars at the corner of the Rigid-Frame structure. Additionally, a full-size model of the reinforced concrete Rigid-Frame bridge with H-shaped steel girders was constructed and subjected to destructive loading tests to evaluate the structural integrity of the proposed Rigid connection and to reveal the load-carrying capacity and failure mode of the bridge. As a result of the loading test, compression failure occurred on the upper surface of the concrete deck at midspan, whereas plasticization and breakage of the fixing nut did not occur in the vicinity of the fixing part. Therefore, the feasibility of the connection approach at the Rigid corner was verified experimentally. In addition, the results of cost analysis showed that the Rigid-Frame bridge could potentially provide significant cost benefits compared to the other bridge structures considered in this study. Notably, regarding the total cost for a life cycle of 100 years, the overall cost of Rigid-Frame bridges was estimated to be approximately 0.49–0.58 of the total expenses for slab bridges. Finally, this work introduced a scheduled inspection procedure with new inspection items corresponding to the proposed bridges by utilizing visual observation in combination with other testing techniques.
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Structural Behavior of Reinforced Concrete Slab Rigid-Frame Bridge with H-Shaped Steel Girders
International Journal of Steel Structures, 2018Co-Authors: Yoshiaki Nakai, Saiji FukadaAbstract:This study aims towards the improvement of a reinforced concrete Rigid-Frame bridge in an effort to reduce the construction and maintenance costs, and achieve an improved seismic performance. Correspondingly, a new structural Rigid connection is proposed for H-shaped steel girders and reinforcing bars at the corner of the Rigid-Frame structure. Both experiments and numerical analyses were performed. Prototype models were constructed and subjected to static loading tests to reveal their load-carrying capacity and failure mode. Numerical models were then developed using finite elements to evaluate the experimental results. Analyses elicited good agreement between simulation and experimental data and validated the numerical models. Moreover, the validity of the proposed Rigid connection was confirmed, and the failure behavior was clarified. Finally, a full-size model of the reinforced concrete Rigid-Frame bridge with H-shaped steel girders was constructed and subjected to destructive loading tests to evaluate structural integrity of the proposed Rigid connection.
Yoshiaki Nakai - One of the best experts on this subject based on the ideXlab platform.
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Method for Construction, Maintenance, and Management of Rigid-Frame Bridges Using H-Shaped Steel Girders
International Journal of Civil Engineering, 2019Co-Authors: Yoshiaki Nakai, Mitsuhiko Tokuno, Saiji FukadaAbstract:This work outlines an actual case study performed on a Rigid-Frame bridge using H-shaped steel girders in the laboratory and introduces the process of construction, maintenance, and management of the proposed bridge structure in practical cases. A novel structural Rigid connection was developed for H-shaped steel girders and reinforcing bars at the corner of the Rigid-Frame structure. Additionally, a full-size model of the reinforced concrete Rigid-Frame bridge with H-shaped steel girders was constructed and subjected to destructive loading tests to evaluate the structural integrity of the proposed Rigid connection and to reveal the load-carrying capacity and failure mode of the bridge. As a result of the loading test, compression failure occurred on the upper surface of the concrete deck at midspan, whereas plasticization and breakage of the fixing nut did not occur in the vicinity of the fixing part. Therefore, the feasibility of the connection approach at the Rigid corner was verified experimentally. In addition, the results of cost analysis showed that the Rigid-Frame bridge could potentially provide significant cost benefits compared to the other bridge structures considered in this study. Notably, regarding the total cost for a life cycle of 100 years, the overall cost of Rigid-Frame bridges was estimated to be approximately 0.49–0.58 of the total expenses for slab bridges. Finally, this work introduced a scheduled inspection procedure with new inspection items corresponding to the proposed bridges by utilizing visual observation in combination with other testing techniques.
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Structural Behavior of Reinforced Concrete Slab Rigid-Frame Bridge with H-Shaped Steel Girders
International Journal of Steel Structures, 2018Co-Authors: Yoshiaki Nakai, Saiji FukadaAbstract:This study aims towards the improvement of a reinforced concrete Rigid-Frame bridge in an effort to reduce the construction and maintenance costs, and achieve an improved seismic performance. Correspondingly, a new structural Rigid connection is proposed for H-shaped steel girders and reinforcing bars at the corner of the Rigid-Frame structure. Both experiments and numerical analyses were performed. Prototype models were constructed and subjected to static loading tests to reveal their load-carrying capacity and failure mode. Numerical models were then developed using finite elements to evaluate the experimental results. Analyses elicited good agreement between simulation and experimental data and validated the numerical models. Moreover, the validity of the proposed Rigid connection was confirmed, and the failure behavior was clarified. Finally, a full-size model of the reinforced concrete Rigid-Frame bridge with H-shaped steel girders was constructed and subjected to destructive loading tests to evaluate structural integrity of the proposed Rigid connection.
Michael J. Brennan - One of the best experts on this subject based on the ideXlab platform.
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acoustic properties of Rigid Frame porous materials an engineering perspective
Applied Acoustics, 2001Co-Authors: Michael J. BrennanAbstract:Sound propagation in Rigid-Frame porous materials is governed by the effective density and the effective bulk modulus of the fluid in the pore space. These quantities, for which analytical expressions have already been derived by other researchers, are frequency-dependent, complex and non-linear. However, because of the complexity of these expressions, it is difficult to obtain physical insight into the acoustic behaviour of the porous materials and to determine the dominant mechanism for sound absorption for a given material at a given frequency. Alternatively there are very simple expressions. In this paper the relationships between the complicated and relatively simple models are studied, and simple non-dimensional expressions for the characteristic impedance and wavenumber for sound propagation in Rigid-Frame porous materials are derived using the concepts of acoustic mass, stiffness and damping. An upper bound for thermal losses in a Rigid-Frame material is presented, and a simple rule of thumb is given for the required flow resistivity, porosity and tortuosity for a given thickness of porous material.
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Acoustic properties of Rigid-Frame porous materials — an engineering perspective
Applied Acoustics, 2001Co-Authors: Michael J. BrennanAbstract:Sound propagation in Rigid-Frame porous materials is governed by the effective density and the effective bulk modulus of the fluid in the pore space. These quantities, for which analytical expressions have already been derived by other researchers, are frequency-dependent, complex and non-linear. However, because of the complexity of these expressions, it is difficult to obtain physical insight into the acoustic behaviour of the porous materials and to determine the dominant mechanism for sound absorption for a given material at a given frequency. Alternatively there are very simple expressions. In this paper the relationships between the complicated and relatively simple models are studied, and simple non-dimensional expressions for the characteristic impedance and wavenumber for sound propagation in Rigid-Frame porous materials are derived using the concepts of acoustic mass, stiffness and damping. An upper bound for thermal losses in a Rigid-Frame material is presented, and a simple rule of thumb is given for the required flow resistivity, porosity and tortuosity for a given thickness of porous material.
Nowshad Amin - One of the best experts on this subject based on the ideXlab platform.
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A practical acoustical absorption analysis of coir fiber based on Rigid Frame modeling
Acoustical Physics, 2012Co-Authors: M Ayub, Mohammad Hosseini Fouladi, Rozli Zulkifli, Nowshad AminAbstract:An analytical study based on Rigid Frame model is demonstrated to evaluate the acoustic absorption of coir fiber. Effects of different conditions such as combination of air gap and perforated plate (PP) are studied in this work. Materials used here are treated as Rigid rather than elastic, since the flow resistivity of coir fiber is very low. The well-known Rigid Frame Johnson-Allard equivalent-fluid model is applied to obtain the acoustic impedance of single layer coir fiber. Atalla and Sgard model is employed to estimate the surface impedance of PP. Acoustic transmission approach (ATA) is utilized for adding various consecutive layers in multilayer structure. Models are examined in different conditions such as single layer coir fiber, coir fiber backed with air gap, single layer PP in combination with coir fiber and air gap. Experiments are conducted in impedance tube on normal incidence sound absorption to validate the results. Results from the measurement are found to be in well agreement with the theoretical absorption coefficients. The performance of the Rigid Frame modeling method is checked more specifically in all conditions, by the mean prediction error rate of normal incidence sound absorption coefficients. Comparison between the measured absorption coefficients and predicted by Rigid Frame method shows discrepancy lower than 20 and 15% for most of the conditions in the frequency range of 0.2–1.5 and 1.5–5 kHz, respectively. Moreover, acoustic absorption of various single and multilayer structures is compared with the simpler empirical methods such as Delany-Bazley and Miki model; and complicated method such as Biot-Allard Model and Allard Transfer Function (TF) method. Comparisons show that the presented method offers a better accuracy of the results than the empirical models. Subsequently, it can provide almost same absorption plot with Biot-Allard model (single layer combination) and TF method (multilayer combination) proving it to be a comprehensively easy and general analytical tool. Therefore, the Rigid Frame model can be implemented relatively easier than other similar models to analyze the acoustic absorption of coir fiber in most of the conditions.
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A practical acoustical absorption analysis of coir fiber based on Rigid Frame modeling
Acoustical Physics, 2012Co-Authors: M Ayub, Mohammad Hosseini Fouladi, Rozli Zulkifli, Nowshad AminAbstract:An analytical study based on Rigid Frame model is demonstrated to evaluate the acoustic absorption of coir fiber. Effects of different conditions such as combination of air gap and perforated plate (PP) are studied in this work. Materials used here are treated as Rigid rather than elastic, since the flow resistivity of coir fiber is very low. The well-known Rigid Frame Johnson-Allard equivalent-fluid model is applied to obtain the acoustic impedance of single layer coir fiber. Atalla and Sgard model is employed to estimate the surface impedance of PP. Acoustic transmission approach (ATA) is utilized for adding various consecutive layers in multilayer structure. Models are examined in different conditions such as single layer coir fiber, coir fiber backed with air gap, single layer PP in combination with coir fiber and air gap. Experiments are conducted in impedance tube on normal incidence sound absorption to validate the results. Results from the measurement are found to be in well agreement with the theoretical absorption coefficients. The performance of the Rigid Frame modeling method is checked more specifically in all conditions, by the mean prediction error rate of normal incidence sound absorption coefficients. Comparison between the measured absorption coefficients and predicted by Rigid Frame method shows discrepancy lower than 20 and 15% for most of the conditions in the frequency range of 0.2–1.5 and 1.5–5 kHz, respectively. Moreover, acoustic absorption of various single and multilayer structures is compared with the simpler empirical methods such as Delany-Bazley and Miki model; and complicated method such as Biot-Allard Model and Allard Transfer Function (TF) method. Comparisons show that the presented method offers a better accuracy of the results than the empirical models. Subsequently, it can provide almost same absorption plot with Biot-Allard model (single layer combination) and TF method (multilayer combination) proving it to be a comprehensively easy and general analytical tool. Therefore, the Rigid Frame model can be implemented relatively easier than other similar models to analyze the acoustic absorption of coir fiber in most of the conditions.
Yang Jianzhong - One of the best experts on this subject based on the ideXlab platform.
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dynamic characteristic analysis of reinforced concrete slant legged Rigid Frame bridge
Journal of North China Institute of Water Conservancy and Hydroelectric Power, 2009Co-Authors: Yang JianzhongAbstract:Combining with the design works of Mudan bridge in Baixiang county of Xingtai city,the general space calculation mode was build for dynamic analysis of the reinforced concrete slant legged Rigid Frame bridge through the finite element software.The dynamic characteristics of the bridge was analyzed,the vibrating types and the values of self-vibrating frequency and cycle were obtained,dynamic calculation measures was put out.It can be a reference for the design of municipal slant legged Rigid Frame bridge.
