Project description

The A4 motorway forms part of the international E40 transport corridor and provides a key east–west connection across Poland. With a total length of more than 670 km, it is the longest high-speed road route in the country.

The completed section of the A4, forming the southern bypass of Kraków, also serves as the city’s ring road and plays a key role in handling traffic between Kraków’s southern districts and the surrounding municipalities.

Key design considerations

Challenges that required precise project coordination.

The motorway runs through areas characterised by weak and organic soils. One of the main challenges was convincing the client to adopt the technical solutions we proposed — ranging from a 2 × 3-lane road cross-section to a foundation method based on so-called vertical drain consolidation. At the time, this was a pioneering solution.

The experience gained during this project was successfully applied in subsequent years. Today, vertical drain consolidation is a widely used method for improving weak soils. It is also worth noting that the pavement structure was designed using the mechanistic method.

The entire design process was supervised by the British engineering consultancy Atkins, while the design documentation was prepared in two language versions — Polish and English. A number of complex technical issues also required cooperation with scientific and research institutions.