Crah-test of road guardrails - 20 tons to the safety barrier!
We visited the advanced guardrail tests at Dmitrov Proving Ground. The spectacle is not for the faint-hearted!
In 2009, at the initiative of “Za Rulem” magazine, a unusual crash test of Priora was carried out at Dmitrov Proving Ground: from a speed of 90 km/h it was pierced into a road guard at an angle of 20 degrees. They killed two birds with one stone: they both tested the barrier and checked the work of the driver's airbag, which then just appeared on the serial Priora.
Similar tests in 2009. Priora dived under the wave profile, hooked on the wheel for support and turned around. Constructive shortcomings of the guardrail are obvious.
I was present at that crash test. Many impressions! After the strike, Priora reversed, ducked under the bump, the wheel caught on one of the supports. In a real accident, this could be fatal for riders: even if the overloads on impact are not prohibitive, a car suddenly crashed across the road may crash another car.
In addition, here I am again on the tests of guardrails - the barrier of a new generation. This time, a heavier Volga was chosen as a victim. Speed of 100 km/h, the same "opposite" angle of 20 degrees, but the Volga did not turn around, but went on a tangent. All because the metal sheet bump, whose thickness is 4 mm has not two but three waves. The lower wave hangs closer to the ground and does not allow the Volga to dive under the bump. Moreover, the machine remained within the conditional dynamic corridor 5 meters wide. As a rule, this space is enough to ensure that after a strike against the guardrail does not appear on the oncoming lane. And this is one of the requirements for such designs. Resisted and the supports themselves: the fixing bolts are screwed into the concrete base, which goes to the ground to a depth of 1 m.
GAZ 31029 weighing about two tons beats against the barrier at a speed of 100 km/h. It is important that the vehicle remain inside a dynamic corridor, marked with a markup. The width of the corridor is five meters.
Evaluation of the barrier deformation. It is not broken, the supports have withstood, and there are no ruptures of the wave profile neither. After receipt of the certificate, the production of the guardrail will begin.
The guardrails, first assembled on the weldless technology, is 15% cheaper than the existing analogs and 29% easier due to optimized height, the pitch of the pillars and the thickness of the steel.
The main feature of the guardrails of this model is the absence of welded joints. This greatly simplifies and speeds up the installation. And, as the test results showed, not to the detriment of security, which remains the main criterion. Barrier guardrails in comparison with barriers of other types are the most effective in minimizing the consequences of the accident. They will not only partially absorb the energy of the impact, but will also prevent a significant expansion of the vehicle fragments, which can exacerbate the consequences of the accident. Only such barriers are allowed to be used on the most dangerous sections of the road. The current GOST, for example, prohibits the use of cheaper cable barriers on the roads of I and II technical categories - on highways, high-speed and some ordinary roads. Only guardrails barriers! The same applies to bridges and overpasses. In the suburbs, as an experiment on the decision of the traffic police the cable barriers are still installed. Barrier bumpers, the cost of which was reduced through unmixed assembly, could be an alternative in this case.
In general, there are two types of fencing - road (holding capacity 130-500 kJ) and bridge (up to 600 kJ). For ease of understanding: the impact energy of 600 kJ develops a projectile with a mass of 20 tons at a speed of 28 km/h. However, this is at right angles. In reality, this happens rarely. Therefore, the collision is carried out at an angle of 20 degrees at a higher speed. Then you cannot get it by with a car. Here the bus is used.
The speed of the bus is 70 km/h. Weight - 20,010 kg. The claimed retention capacity of the barrier is 450 kJ.
The spectacle is not for the faint-hearted, when a three-axle bus MAZ, loaded with ballast up to 20 tons, crashes into the barrier at a speed of about 70 km/h. Why such speed? It is sufficient to confirm the estimated retention capacity of the test barrier under the condition of an allowable dynamic deflection up to 0.7 meters. It was created in Ulyanovsk KTC "Metallokonstruktsiya", where they develop and produce more than 80% of all road barriers in our country. In the arsenal of the enterprise, there are 43 types of holding guardrails and the same number for installation on bridges and overpasses. The maximum retention capacity of some structures reaches 725 kJ. This is more than our standards require, as barriers are exported to other countries, where the standards are often tougher - to Belarus, Kazakhstan, Poland, Iran and others. If in cars we have not yet succeeded, then we succeeded in protection from them.
Alexander Iosifovich Shcherbina, deputy general director of KTC "Metallokonstruktsiya"
Each such test costs one million rubles. The results of the crash test help to identify weaknesses in the design. This time the guardrail withstood the impact: we are satisfied with the results, no improvements are required. The computer simulation was used in the development of this barrier: virtual crash tests make it possible to make major changes in the design even at the design stage. The real crash test only confirmed our calculations.
Text: Konstantin Vasilyev