Glavbolgarstroy (GBS) is the largest construction company in Bulgaria and one of the leadings in Southeastern Europe. The joint ventures “HILL INTERNATIONAL – GBS 1” and “HILL INTERNATIONAL – GBS 3” in which GBS is a leading partner, are responsible for the implementation of LOT 1 (“Looping from Kulata to Kresna”) and LOT 3 (“Looping from Rupcha to Vetrino”) of the Vertical Gas Corridor.

The construction work on LOT 1, which began in 2025, has been completed, and the facility is now in operation. Gas pipeline with a diameter of DN 700 and a length of approximately 48 km (suitable for transportation of noncorrosive natural gas, biomethane, hydrogen and their mixtures) has been constructed along with the associated facilities. The route passes through challenging terrain with steep mountainous sections, crossing rivers, streams and other engineering structures and infrastructure. Within a very short timeframe and despite the diverse and challenging geological conditions, a total of 5 river crossings, each ranging from 400 to 700 m in length, were completed using the Horizontal Directional Drilling (HDD) method.

The construction work on LOT 3 – “Looping from Rupcha to Vetrino”- began just a few months after that on LOT 1 and is still ongoing. Here, the gas pipeline is also suitable for transportation of noncorrosive natural gas, biomethane, hydrogen and their mixtures. The pipeline is approximately 61 km long and has a diameter of DN 1200. The project also includes the construction of 5 technological sites and 3 HDD river crossings.

The two projects are situated in different parts of the country, and their implementation on such a scale and with such complexity require careful planning and coordination of processes, as well as specialized high-tech equipment. Thanks to the team and its solid engineering expertise, the work is strictly organized, ensuring high quality and timely completion.

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