Browsing by Subject "Bridge piers"
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Item Three-Dimensional Simulation of Bridge Foundation Scour on Mississippi River Bridges 9321 & 27801(Center for Transportation Studies, University of Minnesota, 2016-02) Sotiropoulos, Fotis; Khosronejad, AliWe present data-driven numerical simulations of 100- and 500-year floods events in the Mississippi River at its intersection with the Highway I-694 by coupling coherent-structure resolving hydrodynamics with bed morphodynamics under live-bed conditions. The study area is about 1.7 miles long and 220 yard wide reach of the Upper Mississippi River, near Minneapolis MN, which contains several natural islands and man-made hydraulic structures. We employ the large-eddy simulation (LES) and bed-morphodynamic modules of the Virtual Flow Simulator (VFS-Rivers) model, a recently developed in-house code, to investigate the flow and bed evolution of the river along the reach and near the bridge piers BR 27801 and BR 932. We integrate data from airborne Light Detection and Ranging (LiDAR), sub-aqueous sonar apparatus on-board a boat and total station survey to construct a digital elevation model of the river bathymetry and surrounding flood plain, including islands and bridge piers. A field campaign under base-flow condition is also carried out to collect mean flow measurements via Acoustic Doppler Current Profiler (ADCP) to validate the hydrodynamic module of the VFS-Rivers model. Our simulation results for the bed evolution of the river under the 100- and 500-year flood reveal complex sediment transport dynamics near the bridge piers consisting of both scour and refilling events due to the continuous passage of sand dunes. A brief description of the findings in terms of maximum scour depth around individual bridge piers can be found in the executive summary of the report.Item Wakota Bridge Thermal Monitoring Program Part I: Analysis and Monitoring Plan(Minnesota Department of Transportation, 2013-05) Scheevel, Christopher J.; Morris, Krista M.; Schultz, Arturo E.In this work, a common refined design method is evaluated with respect to a recently constructed bridge. Two finite element models of the Wakota Bridge in South St. Paul, Minnesota, were produced, one using a design level program (SAP2000) and the other using a research level program (ABAQUS). These models were verified with respect to each other using linearly elastic materials and were found to behave similarly. After this verification, an arbitrary temperature load was applied to each model and the refined design method was evaluated for accuracy of reduced section properties with respect to the more descriptive progressive cracking solution simulated by ABAQUS. The refined design method was employed using two, four, and six stiffness segments at which stiffness is evaluated along the height of the pier walls. It was seen that accuracy increased as the number of stiffness segments increased and that four segments seemed to balance accuracy and time-commitment by the engineer adequately. A staged construction model of the Wakota Bridge was also built, using the design level program, which incorporates all time-dependent effects of the construction sequence as well as locked-in forces. A pile analysis was performed and appropriate rotational springs were found for Foundations 2 and 3. A simplified method for the determination of the rotational springs is discussed, and a range of effective lengths was found for use with this procedure. The staged construction model is used for field data correlation in Part two of this report. The staged construction model was also used to evaluate the different design options as described in the AASHTO LRFD. The two options given for accounting for reduced section properties were evaluated and compared. The refined analysis option and gross section option were compared for the Wakota Bridge and are shown to correlate to within about 10%. The two temperature application methods (Procedure A and B in the AASHTO LRFD) were also compared. As expected, Procedure B produced much larger design moments than that of Procedure A.Item Wakota Bridge Thermal Monitoring Program Part II: Data Analysis and Model Comparison(Minnesota Department of Transportation, 2013-05) Morris, Krista M.; Schultz, Arturo E.In this work, a common refined design method is evaluated with respect to a recently constructed bridge. Two finite element models of the Wakota Bridge in South St. Paul, Minnesota were produced using a design level program (SAP2000). These models were analyzed and their results compared to the data collected from the bridge. The second half of this study concerned the comparison of the collected field data with the values produced by evaluating the design-level finite element models previously created in Phase I of the project, and calibrating these models to provide an accurate prediction of the future behavior of the bridge. This was done by calculating changes in axial force and moment from strain data collected from the Wakota Bridge and changing various parameters within the design level model (DLM) in order to calibrate the models to the field data. The model using the refined design method was shown to correlate to the superstructure field data to within 2 percent, while between 13 percent and 35 percent correlation was seen between the model deploying the gross section method and the field data. The pier behavior predicted by the two models showed much less correlation to the field data. After calibration, it was possible to predict the general trend of the pier behavior, but the values of changes in moment did not correspond to the field data. This was especially true in Pier 4. Further consideration of the model parameters is necessary to fully calibrate the models. The two temperature application methods (Procedure A and B in the AASHTO LRFD) were also compared. The internal concrete temperature ranges measured in the field were much closer to the range specified in Procedure A.