The risk of rockfall along some sections of the secondary road passing through the enchanting area of the Valnerina has been thwarted, thanks to state of the art protection barriers and metal netting
The earthquake activity during the second half of 2016 threatened the stability and safety of some stretches of the SP209 in Valnerina. High energy absorption rockfall barriers and the Steelgrid® HR50 system are the effective solutions employed by us to quickly restore road usage to the affected areas.
Between August and October 2016, the Amatrice-Norcia-Visso area experienced intense telluric movement which hit the local population hard, destroying buildings, churches, schools and shops, bringing communities to their knees and disrupting entire residential zones.
Among the immediate and most serious results of these events was the substantial damage done to infrastructure, particularly to the road network. In this case, rock faces typical of various stretches of the 209 secondary road long the Valnerina valley which were already precarious, were made even more unstable as a result of the tremours and subsequent earthquake swarms, causing rockfalls and resulting in obstruction of the carriageway.
It was a very real threat that could jeopardise road access and communication with the earthquake zones and slow down aid efforts, putting many lives at risk as a consequence. Quick and effective action was needed that took advantage of the most advanced engineering solutions to not only solve the current situation, but also to prevent similar rockfalls in the future in the event of new seismic episodes.
We worked with ANAS on a long stretch of the SP209 between the 62km and 66.5km marks. The protective measures already in place were plastic rockfall barriers, either rigid or made of molded metal, which were completely inadequate at containing the rocks and boulders, as well as being damaged, further compromising their effectiveness. For this reason, almost 2000 linear metres of state of the art high energy absorption rockfall barriers were installed. In places where the carriageway was directly below the damaged rockface and there was therefore not enough space to install barriers, double-twist wire mesh was used, as well as Steelgrid® HR50, a versatile and easy to install geocomposite which combines the characteristics of double-twist metal mesh with the high mechanical strength typical of metal cables.
There was already a man-made rockfall tunnel at the 63.5km mark, but the seismic episodes had damaged its functionality, so it was decided to demolish it. A rockfall barrier made with reinforced earth with the Green Terramesh system was built in its place, which could guarantee complete safety for cars and was designed to blend in with the contours and colours which make the area of the Valnerina so unique. Finally, two debris-flow barriers were installed in a gorge above the road at the 64.2km mark to prevent further falling rock and debris. This was an additional and effective prevention measure which was installed promptly in order to help restablish normal communication, production activities and the lives of communities along the Nera river.