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Temporary Concrete Barrier

Question
State	IL
Description Text	Has there been any crash testing of Temporary Concrete Barrier (TCB), preferably F-shape, placed on top of a raised concrete median with the edge of the TCB aligned with the face of the curb of the median? If so, what was the median height and what were the results of the crash testing? If not, what is your opinion regarding the effectiveness and safety of freestanding TCB placed on a raised, concrete median?

Question

State

Description Text

Has there been any crash testing of Temporary Concrete Barrier (TCB), preferably F-shape, placed on top of a raised concrete median with the edge of the TCB aligned with the face of the curb of the median? If so, what was the median height and what were the results of the crash testing? If not, what is your opinion regarding the effectiveness and safety of freestanding TCB placed on a raised, concrete median?

System Performance Evaluation

System Types
Portable Barriers

Applications

System Features

Date November 12, 2013
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Response
Response (active)	At this time, there has been not testing or research into the use of TCB installed on a raised median. However, there are concerns with doing so. We know from research with other barrier types and curbs that the presence of the curb can affect the stability of the vehicle and the manner in which it interacts with the barrier. We also know that the sloped faces of most TCB designs tend to increase vehicle climb and instability. Thus, there would be concerns that using TCB on a raised median with a curb may create more vehicle climb and instability than desired. Similar concerns would be present for backside hits in a median installation where the curb would be offset from the barrier face. Another concern is the availability of relatively flat area behind the barrier to accommodate barrier translation during impact. We have typically recommended that users of TCB's provide 4-6 feet of relatively flat (< 10:1 slope) terrain behind the TCB to allow for dynamic deflection of the barriers. Thus, installation on a raised median would require similar area so that the barriers to not slide off the raise median and become unstable or tip. tipping of the barriers would increase the angle of the barrier face, promoting further vehicle instability.

Response

Response
(active)

At this time, there has been not testing or research into the use of TCB installed on a raised median. However, there are concerns with doing so.

We know from research with other barrier types and curbs that the presence of the curb can affect the stability of the vehicle and the manner in which it interacts with the barrier. We also know that the sloped faces of most TCB designs tend to increase vehicle climb and instability. Thus, there would be concerns that using TCB on a raised median with a curb may create more vehicle climb and instability than desired.

Similar concerns would be present for backside hits in a median installation where the curb would be offset from the barrier face.

Another concern is the availability of relatively flat area behind the barrier to accommodate barrier translation during impact. We have typically recommended that users of TCB's provide 4-6 feet of relatively flat (< 10:1 slope) terrain behind the TCB to allow for dynamic deflection of the barriers. Thus, installation on a raised median would require similar area so that the barriers to not slide off the raise median and become unstable or tip. tipping of the barriers would increase the angle of the barrier face, promoting further vehicle instability.

Date November 15, 2013
Previous Views (183) Favorites (0)