Construction site in the Siebengebirge 170 rock spikes to secure crumbling Drachenfels
Siebengebirge · The second part of the major construction at the Drachenfels in Königswinter has begun. But the Eselsweg will only be re-opened next year.
170 rock spikes are being inserted into the porous rocks, while gaps and splits are being closed with a cement mixture. The scaffolding beside the Drachenfels is 53 meters high to enable the workers to reach the upper parts as well. During the preparation for this part of the construction schedule, it became apparent that the rocks are in a much worse state than expected. Thomas Metz, head of the building department of the district government admits: „It is not as stable as it looks from the ground.“ Yet, further delays are not expected. The Eselsweg will be only re-opened next year, as was already announced. The bad weather has caused the recent delays.
„The rock is porous“, explains Metz and hits the wall with a hammer, causing some 50 year old concrete also to shatter. Some of the 400 old and recently checked spikes can be moved by hand easily.
„Those spikes cannot support the rock any longer“, said the expert. Some of them will be replaced, and new ones added in different locations. Coloured markings show where a four-metre long nail needs to be attached to secure the construction. In other places, drilled holes will be filled with pipes and cement to create „a strong bond with the rock“. A cover plate will provide the final stability.
Gaps and splits will be be closed with a cement mixture. „Natural parting lines opened up due to weather conditions over the decades“, says geologist Roland Strauß. What happens if this construction does not get secured, is explained by the expert as follows: „Imagine a tower made from wooden blocks. If you take the bottom block away, the entire construction will crumble.“
The concrete collar around the Drachenfels is also in a serious state. The material became loose and faulty parts need to be reconstructed, the steel will be made corrosion-resistant.
Approximately 40-50 rock spikes were already inserted into the rock. „It’s looking good so far“, says Metz. And: „Everything is going according to plan.“
The finalising of the construction work is scheduled for the end of 2018, maybe early 2019. Only then will the scaffolding be removed and the Eselsweg will be re-opened to the public. If the weather plays along, of course.
Original text: Alexander Hertel
Translation: Mareike Graepel
