Development of Staking Configurations for K-Rail


K-rail PhotoCalifornia's current standard for concrete temporary barrier is K-rail. This barrier, when properly installed, may also be used in semi-permanent applications. K-rail evolved from the Type 50 median barrier, which had been approved for use in California and other states since the mid-1960s. By 1971, there was substantial interest in the U.S. to develop a movable barrier that could be used in work zones. In 1972, the California Department of Transportation ran a series of crash tests on what is now called K-rail. The results of the testing led to the approval of K-rail for use as a temporary barrier in California. The K-rail that has become the standard within California consists of 6.1-m (20-ft) long sections with pin and loop connections, each weighing approximately 3630 kg (8000 lbs).

Eventually, details were developed which also allowed K-rail to be used as a semi-permanent barrier (2-5 years). The configuration of semi-permanent barrier required pin and loop connections between the K-rail segments as well as stakes at each of the four stake holes located in the K-rail. The configuration passed NCHRP Report 350 criteria, but removing the stakes from a paved surface led to expensive repairs and increased worker exposure.

An effort is being made to discover the minimum number of stakes and distance that a K-rail barrier can be placed adjacent to an excavation and as a median barrier before it is no longer compliant with NCHRP Report 350. Minimizing the number of stakes needed in order to achieve a NCHRP Report 350-compliant barrier will save money and worker exposure time.

Tested Staking Configurations

High Speed Crash Test Videos

Test 671 Test 672 Test 673 Test 674  Test 675 Test 676
Test 671 Across
Test 671 Behind
Test 671 Tower-Center
Test 671 Tower-DownS
Test 671 Tower-UpS
Test 671 Upstream
Test 672 Across
Test 672 Behind
Test 672 Tower-Center
Test 672 Tower-DownS
Test 672 Ground
Test 672 Upstream
Test 672 Downstream
Test 673 Across
Test 673 Behind
Test 673 Tower-Center
Test 673 Tower-DownS
Test 673 Tower-UpS
Test 673 Upstream
Test 674 Across
Test 674 Behind
Test 674 Tower-Center
Test 674 Tower-DownS
Test 674 Tower-UpS
Test 674 Upstream
Test 674 Downstream
Test 675 Across
Test 675 Behind
Test 675 Tower-Center
Test 675 Tower-DownS
Test 675 Tower-UpS
Test 675 Upstream
Test 675 Downstream
Test 676 Across
Test 676 Behind
Test 676 Tower-Center
Test 676 Tower-DownS
Test 676 Tower-UpS
Test 676 Upstream

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