4 results
Search Results
Now showing 1 - 4 of 4
Article Citation - WoS: 1Citation - Scopus: 1Experimental Determination of Resistance Characteristics of Support Details Used in Prestressed Concrete Bridge Girders(Asce-amer Soc Civil Engineers, 2009) Baran, Eray; Rohne, Ryan; French, Catherine E.; Schultz, Arturo E.Static load tests were performed on support details used at the ends of prestressed concrete pedestrian bridge girders to determine the resistance characteristics of girder supports in the direction perpendicular to the longitudinal axis of the girders. The specimens tested represent support details that have also been widely used in prestressed concrete highway bridges in Minnesota and in other states. Two specimens, one representing the free-end detail and one representing the restrained-end detail were subjected to a combination of vertical and lateral loads. The applied loading was intended to simulate the loading conditions to which the girder ends would be subjected in the event of an over-height vehicle collision with the bridge. The tests revealed two types of lateral load resisting mechanisms depending on the type of support detail. The specimen with the free-end detail resisted the lateral loading through sliding friction between the components of the support assembly. Deformation of this specimen was a combination of shear deformation of the bearing pad and sliding of various support components. The restrained-end detail exhibited larger lateral load capacity than the free-end detail due to the resistance provided by the anchor rods that were intended to prevent the lateral movement of the girder ends. Failure of the specimen with restrained-end detail was due to the concrete breakout and bending of the anchor rods.Article Citation - WoS: 13Citation - Scopus: 18Reconstruction of Historical Inflows Into and Water Supply From Shasta Dam by Coupling Physically Based Hydroclimate Model With Reservoir Operation Model(Asce-amer Soc Civil Engineers, 2016) Trinh, T.; Jang, S.; Ishida, K.; Ohara, N.; Chen, Z. Q.; Anderson, M. L.; Kavvas, M. L.Long-term water supply data are important for the current practice of water resources management at a target region. However, long-term water outflow data from reservoirs are typically limited at fine time resolution (hourly). In this study, the historical data on water supply from the Shasta Dam were reconstructed by a reservoir operation model with reconstructed reservoir inflow data. Before embarking on this exercise, first the inflow data were reconstructed by means of a watershed environmental hydrology hydroclimate model, with its input provided from historical atmospheric reanalysis data. The reanalysis data used in this study are from the National Center for Atmospheric Research and the National Center for Environmental Prediction (NCAR-NCEP) at spatial resolution of 2.5 degrees (210km at the modeled region). The NCAR-NCEP reanalysis data were dynamically downscaled to 3-km spatial grid resolution at hourly intervals by means of the regional atmospheric component of the hydroclimate model. The downscaled atmospheric data were then used as input to the hydroclimate model hydrologic module for the simulation of snowmelt and runoff conditions over Shasta Dam watershed. Then the reconstructed runoff from the watershed was used as input to a reservoir operation model for regulating outflow from Shasta Dam. The coupled hydroclimate model and reservoir model were successfully validated at Shasta Dam watershed by means of comparisons of the model simulations against the observations. Hence, the combination of proposed models were able to reconstruct the historical water supply data during a 60-year historical period (1950-2010) from Shasta Dam watershed.Article Citation - WoS: 13Citation - Scopus: 23Numerical Analysis of a Tunnel Support Design in Conjunction With Empirical Methods(Asce-amer Soc Civil Engineers, 2008) Sari, Yasin Dursun; Pasamehmetoglu, A. Gunhan; Cetiner, Erkan; Donmez, SenayiIn this paper, preliminary support design of a tunnel was analyzed by numerical and empirical approaches. The case study for this analysis is a tunnel to be constructed on the Bilecik-Istanbul roadway in Turkey. The rock mass properties of the tunnel route and design support recommendations were obtained by using an empirical approach. The rock mass properties obtained from the empirical method were used as input parameters for the numerical analysis. The empirical and numerical results, in terms of support design, were evaluated. It was seen that the numerical analysis results supported by empirical values were logical and reliable.Article Citation - WoS: 25New Methodology To Develop Future Flood Frequency Under Changing Climate by Means of Physically Based Numerical Atmospheric-Hydrologic Modeling(Asce-amer Soc Civil Engineers, 2016) Trinh, T.; Ishida, K.; Fischer, I.; Jang, S.; Darama, Y.; Nosacka, J.; Kavvas, M. L.Effect of climate change on hydrologic flow regimes, particularly extreme events, necessitates modeling of future flows in order to best inform water resources management. This study simulated future flows in the Cache Creek watershed in California over the 21st century using a hydro-climate model (Watershed Environmental Hydrology Hydro-Climate Model; WEHY-HCM) forced by future climate projections. The future climate projections, based on four emission scenarios simulated by two global climate models (GCMs), the fifth-generation atmospheric global climate model and third-generation community climate model (ECHAM5 and CCSM3), under several initial conditions, were dynamically-downscaled using the fifth-generation mesoscale atmospheric model (MM5), a regional climate model. The downscaled future precipitation data were bias-corrected before being input into the WEHY model to simulate the detailed flow at hourly intervals along the main Cache Creek branch and its tributaries during 2010-2099. The results suggest an increasing trend in flood magnitudes and their intensities at the outlet of the study region throughout the 21st century. Similarly, estimates of the 100-year and 200-year floods increased throughout the study period. The observed differences in the estimated future flood frequencies between the first half and the second half of 21st century may be an evidence of the nonstationarity in the 21st century hydrological regime over the study region.
