Advanced work on the construction of the Kroczyce bypass

In Kroczyce, in the Silesian Province, the NDI Group is building a 9-kilometre section of National Road No. 78. The route will be a continuation of the Poręba and Zawiercie bypass. The works are already well advanced – a significant part of the subgrade has been reinforced, the first bridge structures have been built, and asphalt layers have been laid at the roundabout in Żerkowice. The investor of the project is the Katowice branch of the General Directorate for National Roads and Motorways.

The Kroczyce bypass will take over a significant part of transit and regional traffic, thanks to which the current route of DK78 in Kroczyce will only be used by local traffic, which will improve the safety of drivers and residents.

Due to the specific geological conditions of the investment, various methods of ground reinforcement are planned. These include dynamic compaction, filling karst voids with cement grout (in previously drilled boreholes up to 26 metres deep) and laying geosynthetic mattresses. Soil replacement and ground stabilisation are also being carried out.

Dynamic compaction was demanding in terms of implementation. For this task, a 1.5-metre diameter, 20-tonne weight was dropped freely onto the ground from a height of 20 metres. The force of the impact penetrated deep into the ground, compacting it.

At the same time, bridge works are being carried out – three structures made of corrugated sheet metal, 7 metres high and 8 metres wide, have been built, the abutments of another structure have been concreted, and prefabricated box culvert elements have been installed.

Work related to the relocation of power lines and the reconstruction of water mains has been completed. At the roundabout in Żerkowice and on its slip roads, layers of bituminous base and binder courses have been laid. At the same time, the construction of retention reservoirs is underway.

– In the near future, we plan to secure the slopes of the excavations by installing slope nails with a total length of 33,000 running metres and steel meshes to prevent the slopes from sliding. In September, we plan to lay the wearing course on the roundabout in Żerkowice, which will be an important stage in the implementation of the contract. After the horizontal and vertical markings have been completed, traffic will be directed to the roundabout, which will enable the completion of the last link road, Jurajska Street – said Piotr Brzostowski, Construction Manager at the NDI Group. Work will continue on the main route on the next structural layers of crushed aggregate.

‘The construction site is located in the Kraków-Częstochowa Upland, which is why excavations are being carried out in rock, which, after crushing, is used on site as a construction material,’ added the Construction Manager.

The project will include the construction of two roundabouts, one of which will be located in Żerkowice, at the intersection of National Road No. 78 and County Road No. 1773S. Access roads are also to be built, existing roads are to be rebuilt where they collide with the ring road, and pavements, pedestrian and bicycle paths, exits and lighting, vertical and horizontal signage, protective barriers, road fences and acoustic and anti-glare screens are to be constructed.

All work is expected to take 21 months, not including winter breaks.