Performance of Longitudinal Barriers on Curved, Superelevated Roadway Sections (2019) / Chapter Skim
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58 Crash Simulation Analysis of Impacts into Longitudinal Barriers on CSRS 5.1 Introduction This research revealed that there has been little testing or analyses of longitudinal barriers used on CSRS for reasons ranging from the difficulty of testing barriers on such roadways, limited capabilities to employ other approaches, and limited details in crash records that make it hard to isolate incidents involving this specific type of barrier deployment. There have been strides in analyzing barrier effectiveness in varying deployment scenarios using simulation.
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59 the models for small increments of time (e.g., microseconds) over the duration of an impact event (e.g., the vehicle hitting the barrier)
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60 This model was initially validated following traditional protocols for comparison of the data from the full frontal impact with a vertical wall required under the New Car Assessment Program (NCAP) administered by NHTSA and the simulated results for that test.
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61 and each part was cataloged, scanned, measured, and classified by material type. Each part was meshed to create an accurate computer model representing the data gathered in the disassembly, including geometry and material properties.
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62 5.3.1.2 Toyota Yaris Model (1100C) This vehicle model was developed to be used in roadside hardware evaluation, as well as in occupant risk and vehicle compatibility analyses (National Crash Analysis Center 2011)
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63 previously installed and currently being installed barrier on CSRS. • MGS W-beam guardrail with height ≥ 31 in.
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64 • Blockouts were changed from 150 mm × 200 mm × 360 mm (6 in.
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65 is shown in Figure 5.10(b)
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66 at the fixed boundary. The soil block was modeled using eight node hexahedral solid elements.
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67 Test Model Set Up Angular Rotations Change in Velocity N J C on cr et e B ar ri er w / K ia R io 1 10 0C N J C on cr et e B ar ri er w / Si lv er ad o 22 70 P G 4( 1S )
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68 M G S w / D od ge R am 2 27 0P Table 5.3. (Continued)
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69 (a) X-acceleration (b)
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70 Evaluation Criteria Known Result Analysis Result Relative Diff.
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71 5.5 Crash Simulation Parameters The research was initiated to answer a variety of questions over a range of conditions for barriers on CSRS. Over the course of the research, the questions were refined and the focus on critical conditions or situations sharpened.
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72 The barriers in all FE simulations were placed at the edge of the "operational" shoulder. Placement further off the shoulder was found to be an uncommon practice.
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73 • There were no driver inputs (e.g., steering, braking) that affect the vehicle.
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74 5.6.2.1 Influence of Barrier Orientation Figure 5.15 depicts typical results for situations with the same radius, superelevation, and shoulder configurations for the NJ concrete barrier but different barrier orientations. The barriers were installed with normal and vertical orientations.
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75 Parameters and Results Case Time Sequence View CSRS: Radius 614 ft, 12% super Vehicle: 2270P A – Containment (Pass) D – Detached Elements (Pass)
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76 vehicle roll and pitch (e.g., roll 57.53° and 59.73°, and pitch 42.15° and 47.05°) for the pickup.
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77 tions of factors. The simulation analysis generated summary tables to reflect the pass/fail patterns across the various CSRS conditions analyzed.
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78 Parameters and Results Case Time Sequence View CSRS: Radius 614 ft, 12% super Vehicle: 2270P A – Containment (Pass) D – Detached Elements (Pass)
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79 CSRS: Radius: 614 to 3,050 ft; Superelevation: Variable; Shoulder Width: 12 ft; Shoulder Angle: 8% Barrier: MGS; Orientation: Normal; Impact Speed/Angle: 100kmh/25o Parameters and Results Case Time Sequence View CSRS: Radius 614 ft, 12% super Vehicle: 1100C A – Containment (Pass) D – Detached Elements (Pass)
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80 CSRS: Radius: 614 to 2,670 ft; Superelevation: Variable; Shoulder Width: 8 ft; Shoulder Angle: 6% Barrier: G41S (@ 29 in.) ; Orientation: Normal; Impact Speed/Angle: 100kmh/25o Parameters and Results Case Time Sequence View CSRS: Radius 614 ft, 12% A – Containment (Pass)
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81 Notes: * = Barrier performance extrapolated based on other simulation results.
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82 for each of the failed cases. Some efforts to discern the effects of CSRS conditions using analytical means were not successful, given the dispersion effects and interrelationship between factors investigated.
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83 Notes: * = Barrier performance extrapolated based on other simulation results.
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84 Notes: * = Barrier performance extrapolated based on other simulation results.
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85 • The G41S barrier with a height of 27¾ in. had demonstrated vaulting failures in tests and simulations undertaken in other efforts conducted to demonstrate the efficacy of the MASH requirements.
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