Criteria for Restoration of Longitudinal Barriers (2010) / Chapter Skim
Currently Skimming:
Pages 54-60
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 54... ...
11.2 Validation of Finite Element Model Ideally, the validation of strong-post w-beam systems with missing posts could be determined from crash tests, but there were no crash tests to the research team's knowledge with missing posts in unmodified strong-post w-beam guardrail. As an alternative, the finite element model was validated against a crash test of a specialized variation of guardrail called a longspan system (Polivka et al., 1999a; Polivka et al., 1999b)
|
From page 55... ...
posts near the unsupported span. Visually, good agreement was observed between the finite element model predictions and the reported outcome of the OLS2 crash test up to 760 ms.
|
From page 56... ...
Comparison of missing post model results with UNL long-span crash test OLS2. Undamaged 1 Post Missing 2 Posts Missing 3 Posts Missing Impact Conditions Speed (kph)
|
From page 57... ...
-9.9 -7.6 -6.9 2 Max Yaw (deg) 40.3 23.8 37 40 Max Rail Tension (kN)
|
From page 58... ...
Undamaged 1 Post Missing 2 Posts Missing 3 Posts Missing Figure 49. Maximum dynamic deflection contours; impacts at the beginning of the unsupported span (left)
|
From page 59... ...
This has been attributed to the development of high localized stresses around the splices in full-scale crash tests. Localized tearing is possible in impacts where posts are missing, but the finite element model was not configured to look for element tearing resulting from localized stress concentrations because the model did not include any failure criteria for the steel components.
|
From page 60... ...
Impacts into guardrail systems with missing posts were found to have a higher risk of vehicle instability, greater maximum guardrail deflection, and an increased risk of rail rupture. Damage Mode Repair Threshold Relative Priority Missing/Broken Posts 1 or more posts missing Cracked across the grain Broken Rotted With metal tears High Exhibit 8.0.
|
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.