Measures to drain stormwater on the Lijak viaduct

28.02.2020

The Lijak viaduct is located on the H4 express road. This is a 42.1 km section of the four-lane driveway through the Vipava valley between the Nanos junction and the abandoned Vrtojba border crossing into Italy. In addition to renewing the expansion joints, all stormwater drainage pipes were replaced on both viaducts and two pot bearings on the Lijak-L viaduct.

As a part of the reconstruction, a replacement of the stormwater drainage system and the access control door was carried out.

The existing cast-iron piping was in poor condition due to corrosion, which is why it had to be completely removed from the bridge drainers to the stormwater sewer shafts at the main viaduct pillars. We implemented the new system by providing identical functionality. We used the connections with bridge drainers DN 150 and the connection to the main horizontal connection pipe DN 200. The discharges were joined via new RF funnels into six vertical pipelines DN 250 in a total length of approx. 1.300 meters. About 160 separate connections were made to the existing discharges. The pipeline was led into the stormwater soakway through the collection shafts via the vertical pipelines DN 250. Furthermore, a stormwater discharge from the expansion joints into the horizontal pipe system DN 200 was provided for the new expansion joints under the viaduct.

The POLO-ECO Plus Premium 12, Bridge Drainage DN160/DN250 System by the Austrian supplier Poloplast GmbH & Co KG was used in the reconstruction project. The system consists of pipes, fittings and connecting elements specially adapted to the conditions and methods of draining stormwater from bridges. The pipes have a hot-extruded three layer polypropylene (PP) coating to ensure the best possible physical and chemical resistance. The pipelines exhibit a circumferential stiffness of SN ≥ 12 kN/m2, which even exceeds the pipeline design requirements.

The Polo-ECO Plus Premium 12 system complies with the highest requirements of Guidelines and Regulations or Road Traffic in Austria (RVS 15.04.31) and has been approved for all the required EN standards (EN 1259-1, EN 1610, EN 476).

As part of the renovation project, new ladders were installed to access the expansion joint areas under the bridge, and a new aluminium door.

As all the work in the period from May to July 2018 was carried out in the motorway buffer zone, the road capacity was not impaired.