Friction is treated in the usual way. To simulate the actual connection of the rail system to a bridge, each parapet was constructed on top of a 203. The concrete used for the bridge deck had an average compressive strength of 35. The simulation matches particularly well with test P4. The parapet-only model of the T4 parapet system with four-bolt anchorage and 254-mm- 10-inch- wide parapet discussed previously was used in the simulation to reduce computational time. First, the tests provide an opportunity to assess the concrete model in a roadside safety application.
Fracture profile for T4 bridge rail with four-bolt anchorage for parapet and eroded elements. However, an alternate meshing strategy with a biasing scheme was ultimately used in the evaluation to provide desired refinement in critical areas of the model without significantly affecting the overall size and run time of the model. The calculations included three concrete impact simulations that correlate with bogie impact tests of reinforced concrete beams, and two drop-tower simulations that correlate with drop-tower tests. Linear mesh biasing along the height of parapet and width of deck. Concrete and reinforcement types 7 and 8 have been added to reflect changes to Eurocode 2. It is divided into an elastic- plastic compaction model that is supposed to be run in a first phase, and a viscoelastic sintering model that should be run in a second phase.
Longitudinal reinforcement in the parapets consisted of two 5 bars equally spaced at the top of each parapet and within the V bars. At present, only rcforc and jntforc are implemented. The extent to which the calculations are affected by this behavior is not known. Additional support calculations conducted by the developer are given in appendix B. The anchor bolts are also constrained to the steel base plate via node merging. Previous experience with the original model with honeycomb nose required runtimes of around 8 central processing unit hours on a mainframe computer to complete a calibration run with the pendulum impacting a rigid pole.
G fc Fracture energy in uniaxial compression. The feature is no longer limited to horizontal plates. Figure 43 shows that the peak acceleration for test P7 exceeds that for test P5 and the simulation. After calibration of the material model parameters and enhancement of the base plate connection model, simulations of the two bridge rail alternatives were able to capture the general pattern and severity of concrete damage observed in pendulum tests of both the 254-mm- 10-inch- and 317. Figures 100 and 101 show the steel reinforcement and anchor bolts incorporated into the four-bolt and three-bolt parapet models, respectively. A removed part was also removed from contact definition. No element erosion occurred in the analysis.
First, in consultation with the developer, the stiffness of the crushable nose of the pendulum impactor was studied to see whether the impact energy absorbed by the pendulum and transferred to the barrier agreed with test data. Beam elements were used to model the anchor bolts and steel reinforcement inside the parapet and bridge deck. Hallquist had consulted for nearly 6. If only the 1st card is defined, the refinement occurs during the initialization. Summary for Bridge Rail Analyses The analyses of the T4 bridge rail alternatives provided a good benchmark for evaluating the application of the new concrete material model in roadside safety applications. The contact was working correctly, but the energy calculation was incorrect since the changes of r. Recall that no visible damage was observed after test P5, and only small hairline cracks were found after test P7.
This test was selected because no damage to the parapet was observed after the test. Enhanced anchor bolt-to-base plate connection model. A model of a safety-shape bridge rail with New Jersey profile was developed for this purpose. It was analytically verified through careful monitoring of bolt stresses that none of the anchor bolts reached yield stress at any time during simulation. Input parameters are not listed here because they are explained in the companion Users Manual for the material model.
Discrete Elements Springs and Dampers Lumped Inertias. This constraint is illustrated in Figure 108. The bridge deck was meshed uniformly along its length using an element size of 25. Very similar to option 2 but insensitive to pressure. Further investigation revealed that this unrealistic increase in energy, shown in Figure 115, was traceable to the concrete material. Thus, the calibration process involved applying a prescribed displacement to the elliptical steel rail.
The work plan followed in the model evaluation process consisted of two tasks. This keyword was developed for blank size development in sheet metal forming. After converging on a reasonable set of parameters, the full system models including bridge deck were simulated and the results compared to measured and observed test data. Figure 127 shows the calculated response of the parapet-deck system after being impacted by the pendulum. As the research progressed, it was observed that the impact forces imparted by the pendulum model did not correspond to those measured in the pendulum tests. Because proper load application is critical to evaluating barrier damage and the concrete material model, a recalibration exercise was undertaken.
Finite Element Model of T4 Bridge Rail Finite element analysts typically follow certain procedures before and after running the numerical solver to help maintain quality control and achieve efficient analysis. Finally, the two design variations demonstrated different levels of damage and, therefore, provide the ability to assess sensitivity of the concrete model to small design changes under similar loading conditions. Generally, for a single forming process, only the option. Extra history variables for reinforcement stress and strain are now output as zero for zero- fraction reinforcement directions. Because the test specimens and impact conditions are nominally similar, this difference is attributed to normal material and test variation.