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Safety provisions Serpentine Road


The Karaganski Rock Load-out Facility (KRLF) project was built in 2002/2003 to facilitate the transportation of rock for the OKIOC/AgipKCO construction programs for the islands at the Kashagan oilfield.

Witteveen+Bos Kazakhstan, in cooperation with NIPIneftegas, have designed the Serpentine Road for OKIOC. The present owner of the road is TenizService. The road consists of two sections: a horizontal section from the quarry to the top of the escarpment and the so-called Serpentine Road, which runs from the upper terrace down to the sea level, to the load-out station. AgipKCO have decided to further improve the safety of the Serpentine Road with a focus on the five critical downhill sections.

Design of modifications for the bend from the top of the escarpment has been carried out by Witteveen+Bos Kazakhstan. The design is based on a safety philosophy that focusses on issues such as the effects of forces on the body and rapid forward deceleration.

A two step approach for a gravel stop ramp and a barrier with water filled oil drums has been chosen due to the ability of these materials to absorb and to transfer a maximum of kinetic energy, causing the least damage to the occupant of the truck in the process. The first layer of protection, the gravel stop ramp, will bring a fully loaded truck of 50 tons to an (almost) complete stop. The second layer of protection, if there is energy left, the truck will hit the water filled drums, with minimum consequences for the occupant of the truck.

Total length of the Serpentine Road in the first bend is about 500 m; the existing drain is filled with gravel and thus creates a 4 m wide shoulder with loose high density gravel between the pavement of the road and the slope of the adjacent hill. An HDPE drain pipe is installed at the bottom of the concrete drain.

Calculations for the stop ramp have been carried out on truck behavior, stop time and stop length from normal situation till worst case scenario, taking into account that the truck is driving in low gear, high gear and free gear. Kinetic energy calculations have been carried out for the water filled drums.

To prevent adding an additional steering difficulty for the driver, dedicated entrances of about 30 m will guide the truck from the road onto the gravel shoulder.

A third and last layer of protection is at the end of the bend. Here a dead man's stop is constructed, that will prevent a truck, after the gravel stop ramp and the drums, from falling off from the embankment into the ravine.