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D Huang - One of the best experts on this subject based on the ideXlab platform.
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Impact Factors Of Curved Steel Box Girder Bridges
2008Co-Authors: D HuangAbstract:The dynamic loading of 28 three-span continuous single Box Girder Bridges and 216 three-span continuous multi-Box-Girder Bridges, with span lengths ranging from 22.83-30.48-22.86 m to 64.01-85.34-60.01 m (75-100-75 ft to 210-218-210 ft), due to vehicles moving across rough bridge decks is analyzed. The curved single Box Girder Bridges are divided into a number of thin-walled beam elements. The curved multi-Box-Girder bridge is modeled as a curved grillage system. The analytical vehicle, simulated as a nonlinear vehicle model with 11 degrees of freedom, is the HL-93 truck as described in the American Association of State Highway and Transportation Officials (AASHTO) specifications. Truck parameters include the body, suspensions, and tires. The bridge deck surface is assumed to be classed “good” and is simulated using a stochastic process (power spectral density function). The bridge-vehicle interaction model is validated by field test results from two curved steel Box Bridges. The analytical results show that the torsion impact factors for curved Box Girder Bridges can be relatively high, while moment, shear and deflection impact factors are normally less than those of corresponding straight Box Girder Bridges due to restricted vehicle speed on curved Bridges. The proposed simplified impact equations are appropriate for the design of both curved single Box and multi-Box Box Girder Bridges.
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Dynamic loading of curved steel Box Girder Bridges due to moving vehicles
Structural Engineering International, 2008Co-Authors: D HuangAbstract:This paper presents a simplified method for determining the dynamic loading of curved steel Box Girder Bridges due to vehicles moving across rough bridge decks. The curved single Box Girder Bridges are divided into a number of thin-walled beam elements. The curved multi-Box Girder Bridges are modeled as a curved grillage system. The analytical vehicle, simulated as a non-linear vehicle model with 11 degrees of freedom, is the HL-93 truck as described in the American Association of State Highway and Transportation Officials (AASHTO) specifications. Truck parameters include the body, suspensions, and tires. The bridge deck surface is simulated using a stochastic process (power spectral density function). The dynamic loading of 28 three-span continuous single Box Girder Bridges and 216 three-span continuous multi-Box Girder Bridges, with span lengths ranging from 22,83-30,48-22,86 m to 64,01-85,34-60,01 m is analyzed. The analytical results show that the torsion impact factors for curved Box Girder Bridges can be relatively high, while moment, shear, and deflection impact factors are normally less than those of corresponding straight Box Girder Bridges due to restricted vehicle speed on curved Bridges. The proposed simplified impact equations are appropriate for the design of both curved single Box and multi-Box Girder Bridges. (A)
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dynamic test and analysis of curved steel Box Girder Bridges
Transportation Research Record, 2005Co-Authors: D HuangAbstract:This paper presents experimental and analytical impact factors for two existing curved steel Box Girder Bridges. A Florida Department of Transportation test truck with a total weight of 468.8 kN applied the dynamic loading. The truck speed was incrementally increased from crawl to design speed. To evaluate the test results, the truck was simulated as a nonlinear vehicle model with 15 degrees of freedom. The bridge deck surface was assumed to be good and was simulated as a random process. Test and analytical results show that the impact factors of torsion are normally less than 30%, as are the impact factors of bending moment for Bridges with span lengths less than 39 m. The impact factors of vertical shear are generally less than 15%, as are the impact factors of bending moment for Bridges with span lengths greater than 50 m. The current AASHTO Guide Specifications for Horizontally Curved Highway Bridges appears to overestimate the dynamic loading of curved steel Box Girder Bridges, especially for Bridges...
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DYNAMIC ANALYSIS OF STEEL CURVED Box Girder Bridges
Journal of Bridge Engineering, 2001Co-Authors: D HuangAbstract:The impact of seven three-span continuous single Box Girder Bridges, with overall span lengths ranging from 76.2 to 213.36 m (250–700 ft), due to vehicles moving across rough bridge decks is analyzed. The Box Girder is divided into a number of thin-walled beam elements. Both warping torsion and distortion are considered in the study. The analytical vehicle is the HS20-44 truck included in the American Association of State Highway and Transportation Officials specifications and simulated as a nonlinear vehicle model with 11 degrees of freedom. Truck parameters include the body, suspensions, and tires. The bridge deck surface is assumed to be good and was simulated using a stochastic process (power spectral density function). The analytical results show that the impact factors of torque and distortional torque for the curved single Box Girder Bridges could be very high, while those of the other responses are generally less than that of corresponding straight Box Girder Bridges. The proposed impact equations can be used in the design of continuous curved single Box Girder Bridges.
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VEHICLE IMPACT IN Box Girder Bridges: PHASE II, CURVED Box Girder Bridges
1997Co-Authors: T. L. Wang, D HuangAbstract:This is the final part of the two-phase project on vehicle impact in Box Girder Bridges. The objective of this investigation is to develop a procedure for obtaining the dynamic response of thin-walled curved Box Girder Bridges due to truck loading and to get their basic impact characteristics. In this study, the Box Girder bridge is divided into a number of thin-walled beam elements. Both warping torsion and distortion are considered in the study. The analytical vehicle is the AASHTO HS20-44 truck simulated as a nonlinear vehicle model with 11 independent degrees of freedom. Four different classes of road-surface roughness generated from power spectral density function for very good, good, average, and poor roads are used in the analysis. In comparison with the other approaches developed by former investigators, the proposed procedure not only facilitates a physical understanding of the general structural response, but also greatly reduces the computing time required and output obtained. The analytical results show that most impact factors of torsion and distortion are greatly larger than those of vertical bending response. The impact factors of normal stress at different points in a same cross section are quite different. The larger the normal stress, the smaller the impact factor will be. Though the static normal stresses at different positions in a same cross section may be extremely different for a curved Box Girder bridge, their dynamic normal stresses tend to be uniform.
Mohsen Shahawy - One of the best experts on this subject based on the ideXlab platform.
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Dynamic Behavior of Continuous and Cantilever Thin-Walled Box Girder Bridges
Journal of Bridge Engineering, 1996Co-Authors: T. L. Wang, D Huang, Mohsen ShahawyAbstract:The free vibration characteristics and the dynamic response to a multivehicle load moving across rough bridge deck of continuous and cantilever thin-walled Box Girder Bridges are studied. The Box Girder bridge is divided into a number of thin-walled beam elements. Both warping torsion and distortion are considered in the study. The analytical vehicle is simulated as a nonlinear vehicle model with 11 independent degrees of freedom according to the HS20-44 truck design loading contained in the AASHTO specifications. Four different classes of road-surface roughness generated from power spectral density function for very good, good, and average roads are used in the analysis. One continuous and two cantilever three-span Box Girder Bridges are designed based on the AASHTO specifications. The dynamic responses of the Bridges are evaluated for single truck, three, and six trucks, with different speeds and road surface roughness. The analytical results show that the effects of different loading models, road surface profiles, and vehicle speeds on the dynamic response for different types of Bridges are quite different. The most important factor which affects the impact of cantilever Bridges is the vehicle speed. namic characteristics and impact of continuous and cantilever Box Girder Bridges with different vehicle models, road surface roughnesses, as well as vehicle speeds. In the present study, the bridge is modeled as a thin-walled structure with deform able cross sections. The traveling vehicle is treated as a non linear space model. Multitruck loading is considered in both transverse and longitudinal directions of the bridge. The results obtained in this study are significant for both practical bridge design and further theoretical study of continuous and canti lever Box Girder Bridges.
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vibration of thin walled Box Girder Bridges excited by vehicles
Journal of Structural Engineering-asce, 1995Co-Authors: D Huang, T. L. Wang, Mohsen ShahawyAbstract:This paper presents a procedure for obtaining the dynamic response of thin-walled Box-Girder Bridges due to truck loading. The Box-Girder bridge is divided into a number of thin-walled beam elements. Both warping torsion and distortion are considered in the study. The analytical vehicle is the American Association of State Highway Transportation Officials (AASHTO) HS20-44 truck simulated as a nonlinear vehicle model with 11 independent degrees of freedom. Four different classes of road-surface roughness generated from power spectral density function for very good, good, average, and poor roads are used in the analysis. The proposed procedure has been checked against the folded-plate method studied by former investigators. The comparison between these two methods is very good. The analytical results show that the dynamic response of vertical bending moment is caused mainly by several vibration modes, and that of torsion and distortion is greatly affected by the higher modes.
T. L. Wang - One of the best experts on this subject based on the ideXlab platform.
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VEHICLE IMPACT IN Box Girder Bridges: PHASE II, CURVED Box Girder Bridges
1997Co-Authors: T. L. Wang, D HuangAbstract:This is the final part of the two-phase project on vehicle impact in Box Girder Bridges. The objective of this investigation is to develop a procedure for obtaining the dynamic response of thin-walled curved Box Girder Bridges due to truck loading and to get their basic impact characteristics. In this study, the Box Girder bridge is divided into a number of thin-walled beam elements. Both warping torsion and distortion are considered in the study. The analytical vehicle is the AASHTO HS20-44 truck simulated as a nonlinear vehicle model with 11 independent degrees of freedom. Four different classes of road-surface roughness generated from power spectral density function for very good, good, average, and poor roads are used in the analysis. In comparison with the other approaches developed by former investigators, the proposed procedure not only facilitates a physical understanding of the general structural response, but also greatly reduces the computing time required and output obtained. The analytical results show that most impact factors of torsion and distortion are greatly larger than those of vertical bending response. The impact factors of normal stress at different points in a same cross section are quite different. The larger the normal stress, the smaller the impact factor will be. Though the static normal stresses at different positions in a same cross section may be extremely different for a curved Box Girder bridge, their dynamic normal stresses tend to be uniform.
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Dynamic Behavior of Continuous and Cantilever Thin-Walled Box Girder Bridges
Journal of Bridge Engineering, 1996Co-Authors: T. L. Wang, D Huang, Mohsen ShahawyAbstract:The free vibration characteristics and the dynamic response to a multivehicle load moving across rough bridge deck of continuous and cantilever thin-walled Box Girder Bridges are studied. The Box Girder bridge is divided into a number of thin-walled beam elements. Both warping torsion and distortion are considered in the study. The analytical vehicle is simulated as a nonlinear vehicle model with 11 independent degrees of freedom according to the HS20-44 truck design loading contained in the AASHTO specifications. Four different classes of road-surface roughness generated from power spectral density function for very good, good, and average roads are used in the analysis. One continuous and two cantilever three-span Box Girder Bridges are designed based on the AASHTO specifications. The dynamic responses of the Bridges are evaluated for single truck, three, and six trucks, with different speeds and road surface roughness. The analytical results show that the effects of different loading models, road surface profiles, and vehicle speeds on the dynamic response for different types of Bridges are quite different. The most important factor which affects the impact of cantilever Bridges is the vehicle speed. namic characteristics and impact of continuous and cantilever Box Girder Bridges with different vehicle models, road surface roughnesses, as well as vehicle speeds. In the present study, the bridge is modeled as a thin-walled structure with deform able cross sections. The traveling vehicle is treated as a non linear space model. Multitruck loading is considered in both transverse and longitudinal directions of the bridge. The results obtained in this study are significant for both practical bridge design and further theoretical study of continuous and canti lever Box Girder Bridges.
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vibration of thin walled Box Girder Bridges excited by vehicles
Journal of Structural Engineering-asce, 1995Co-Authors: D Huang, T. L. Wang, Mohsen ShahawyAbstract:This paper presents a procedure for obtaining the dynamic response of thin-walled Box-Girder Bridges due to truck loading. The Box-Girder bridge is divided into a number of thin-walled beam elements. Both warping torsion and distortion are considered in the study. The analytical vehicle is the American Association of State Highway Transportation Officials (AASHTO) HS20-44 truck simulated as a nonlinear vehicle model with 11 independent degrees of freedom. Four different classes of road-surface roughness generated from power spectral density function for very good, good, average, and poor roads are used in the analysis. The proposed procedure has been checked against the folded-plate method studied by former investigators. The comparison between these two methods is very good. The analytical results show that the dynamic response of vertical bending moment is caused mainly by several vibration modes, and that of torsion and distortion is greatly affected by the higher modes.
In-hwan Yang - One of the best experts on this subject based on the ideXlab platform.
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uncertainty and updating of long term prediction of prestress forces in psc Box Girder Bridges
Computers & Structures, 2005Co-Authors: In-hwan YangAbstract:The purpose of the present paper is to propose a method of uncertainty analysis and sensitivity analysis of the effects of creep and shrinkage in prestressed concrete (PSC) Box Girder Bridges. Also, a method to reduce the uncertainty of long-term prediction of time-dependent effects due to creep and shrinkage of concrete is developed. The study deals with the uncertainties in the long-term prediction of creep and shrinkage effects using sampling method. Partial rank correlation coefficient and standardized rank regression coefficient computed on the ranks of the observations are examined to quantify the sensitivity of the outputs to each of the input variables. Updating of long-term prediction is achieved using Bayesian statistical inference. The proposed theory is applied to long-term prediction of prestress force of an actual PSC Box Girder bridge. The numerical results indicate that the creep model uncertainty factor and relative humidity appear to be the most dominant factors with regard to the model output uncertainty. The present study indicates that the width of mean+/-two standard deviation for updated predictions of prestress forces with nine measurement information is about half of that of mean+/-two standard deviation for prior prediction of prestress forces. Therefore, the adoption of an approach developed in this study would reduce the uncertainties of prediction of time-dependent effects due to creep and shrinkage and improve greatly the long-term serviceability of PSC Box Girder Bridges.
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Probabilistic analysis of creep and shrinkage effects in PSC Box Girder Bridges
KSCE Journal of Civil Engineering, 2003Co-Authors: In-hwan YangAbstract:This paper presents a method of probabilistic analysis and a sensitivity analysis of the effects of creep and shrinkage in prestressed concrete (PSC) Box Girder Bridges. Three possible sources of the uncertainties of the structural response have been considered: (1) creep and shrinkage model uncertainty, (2) parameter variation, and (3) environmental conditions. The probabilistic and sensitivity analyses are performed using sampling method. For each sample, a time-dependent structural analysis is performed to produce response data, which are then analyzed statistically. Two measures are examined to quantify the sensitivity of the outputs to each of the input variables. These are partial rank correlation coefficient (PRCC) ad standardized rank regression coefficient (SRRC) computed on the ranks of the observations. To apply the proposed method to a real structure, the probabilistic prediction and sensitivity of the time-dependent axial shortening of PSC Box Girder bridge are analyzed. The method provides a realistic tool to determine the uncertainty analysis in PSC Box Girder Bridges and identifies the most important factors in the long-term prediction of structural response of those structures.
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sensitivity analysis of time dependent behavior in psc Box Girder Bridges
Journal of Structural Engineering-asce, 2000Co-Authors: In-hwan YangAbstract:This paper describes a method of statistical analysis and a sensitivity analysis of the effects of creep and shrinkage in prestressed concrete (PSC) Box Girder Bridges. Three possible sources of the uncertainties of the structural response have been taken into account: creep and shrinkage model uncertainty, parameter variation, and environmental conditions. The statistical and sensitivity analyses are performed using the Latin hypercube sampling method. For each sample, a time-dependent structural analysis is performed to produce response data, which are then analyzed statistically. Two measures are examined to quantify the sensitivity of the outputs to each of the input variables. These are the partial rank correlation coefficient and the standardized rank regression coefficient computed on the ranks of the observations. To apply the proposed method to a real structure, the uncertainty and sensitivity of the time-dependent axial shortening of a PSC Box Girder bridge are analyzed. The results indicate that the creep model uncertainty factor and relative humidity appear to be the most dominant factors with regard to the model output uncertainty. The method identifies the most important factors in the long-term prediction of structural response in PSC Box Girder Bridges and provides a realistic method to determine the uncertainty analysis of those structures.
J H Kim - One of the best experts on this subject based on the ideXlab platform.
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A study on thermal behaviour of curved steel Box Girder Bridges considering solar radiation
Archives of Civil and Mechanical Engineering, 2009Co-Authors: Sang Hyo Kim, K I Cho, J H Won, J H KimAbstract:Promieniowanie słoneczne powoduje niejednorodny rozkład temperatury w konstrukcji mostu i zależny od jego kształtu oraz padających cieni. Szczególnie w przypadku mostów zakrzywionych ze stalowych dźwigarów skrzynkowych niejednorodny rozkład temperatur wywołany promieniowaniem słonecznym może prowadzić do powstania wyjątkowych sił wystarczających do zniszczenia podpór lub nawet zniszczenia mostu, o ile jego konstrukcja nośna nie została odpowiednio zaprojektowana. Obecnie projektowanie mostów z uwzględnieniem promieniowania słonecznego jest bardzo trudne, ponieważ wpływ zmiennego rozkładu temperatury na konstrukcję mostu nie jest dokładnie znany, jak również nie jest określony sposób uwzględnienia tych wpływów w projektowaniu. Nie istnieją również żadne normy dotyczące tego zagadnienia. W pracy przedstawiono analizę zachowania mostu uwzględniającą działanie promieniowania słonecznego. Do analizy użyto metodę przewidywania trójwymiarowego rozkłady temperatury w mostach zakrzywionych w planie. W metodzie tej wykorzystane zostało teoretyczne równanie promieniowania słonecznego oraz program do analizy metodą elementów skończonych. Przeprowadzono badania zachowania mostu przy uwzględnieniu różnych zakresów kąta azymutu oraz promieni zakrzywienia mostu. Praca stanowi źródło — możliwych do wykorzystania w projektowaniu — informacji dotyczących zagadnień termicznych w mostach zakrzywionych o przęsłach ze stalowych dźwigarów skrzynkowych pod wpływem promieniowania słonecznego. Solar radiation induces non-uniform temperature distribution in the bridge structure depending on the shape of the structure and shadows cast on it. Especially in the case of curved steel Box Girder Bridges, non-uniform temperature distribution caused by solar radiation may lead to unusual load effects enough to damage the support or even topple the whole curved bridge structure if not designed properly. At present, it is very difficult to design Bridges in relation to solar radiation because it is not known exactly how varying temperature distribution affects Bridges; at least not specific enough for adoption in design. Standard regulations related to this matter are likewise not complete. In this study, the thermal behavior of curved steel Box Girder Bridges is analyzed while taking the solar radiation effect into consideration. For the analysis, a method of predicting the 3-dimensional temperature distribution of curved Bridges is used. It uses a theoretical solar radiation energy equation together with a commercial FEM program. The behavior of the curved steel Box Girder Bridges is examined using the developed method, while taking into consideration the diverse range of bridge azimuth angles and radii. This study also provides reference data for the thermal design of curved steel Box Girder Bridges under solar radiation, which can be used to develop design guidelines.
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a study on thermal behaviour of curved steel Box Girder Bridges considering solar radiation
Archives of Civil and Mechanical Engineering, 2009Co-Authors: Sang Hyo Kim, K I Cho, J H Won, J H KimAbstract:Solar radiation induces non-uniform temperature distribution in the bridge structure depending on the shape of the structure and shadows cast on it. Especially in the case of curved steel Box Girder Bridges, non-uniform temperature distribution caused by solar radiation may lead to unusual load effects enough to damage the support or even topple the whole curved bridge structure if not designed properly. At present, it is very difficult to design Bridges in relation to solar radiation because it is not known exactly how varying temperature distribution affects Bridges; at least not specific enough for adoption in design. Standard regulations related to this matter are likewise not complete. In this study, the thermal behavior of curved steel Box Girder Bridges is analyzed while taking the solar radiation effect into consideration. For the analysis, a method of predicting the 3-dimensional temperature distribution of curved Bridges is used. It uses a theoretical solar radiation energy equation together with a commercial FEM program. The behavior of the curved steel Box Girder Bridges is examined using the developed method, while taking into consideration the diverse range of bridge azimuth angles and radii. This study also provides reference data for the thermal design of curved steel Box Girder Bridges under solar radiation, which can be used to develop design guidelines.