Figure 118. The post breaks by 15 milliseconds in this Douglas fir simulation (default saturated Grade 1 properties without rate effects). Diagrams.

5 milliseconds.

This figure shows a computer-generated illustration of a post embedded in a concrete brace using the double flap method.  The sleeves can be seen on either side of the post, folded over at the entry point.  The majority of the post is colored yellow with only a small section near the top colored red and representing the impact point and another small section colored red representing the breaking area.  This latter area is the area in which the post is embedded into the concrete brace.  No damage to the post is as of yet apparent.

10 milliseconds.

This figure shows the post leaning further to the right.  A gap has formed in the red “breaking area” section of the post, running nearly the entire width of the post.  The break, which has formed, is uneven in nature.

15 milliseconds.

This figure shows the post leaning to the right at a rough twenty-five degree angle.  The gap in the red “breaking area” has widened the top half of the post now appearing severed from the lower half of the post.  The break still remains uneven.

50 milliseconds.

This figure shows the top half of the post leaning at a rough fifty-degree angle, now completely severed from the lower half and existing well outside the original entry point.  Some minor damage appears to have occurred to the impact area as well, with a small dent in the post visible in this area.

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FHWA-HRT-05-096