Passage through Powder Bridge Embankment on Prague Castle

Prague Castle Administration

Divize 5, Metrostav a.s.
Na Zatlance 1350/13, 150 00 Prague 5 

AP Atelier - Křístek, Trčka a spol., s. r. o.
Metroprojekt, a. s.

04/2001 - 08/2002

Dagmar a Václava Havlových VIZE 97 
Prague Castle Administration

The Jelení Ditch used to be crossed over a wooden bridge on two walled pillars. In the 18th century, the bridge was destroyed and replaced with an earth-fill embankment. This divided the Jelení Ditch into the lower part and upper part. The goal of the ordering party was to renew the connection between the lower and upper part of the Jelení Ditch for walking visitors of the Prague castle.

 

The embankment was cut with a U-shaped gallery of a considerably surmounted profile of approximately 80 meters of length. The route is in line with the uniform gradient towards the lower Jelení Ditch. The gallery was driven in two phases - first the upper part (calotte) and subsequently the lower part and the bottom. Partially, the  New Austrian Tunnelling method was used. In the course of driving, the walled construction of a gallery from the 18th century that drained water to the Brusnice brook was destroyed. The gallery has a single-layer support construction with no insulation and formed by steel-armoured shot concrete. The internal, non-supportive, suspension vaulting was walled with baked bricks laid atypically edge-on. The gallery bottom is made deeper and is traversed by the Brusnice Brook. Approximately in the middle of the gallery, there is a recess with the rests of an original pillar of the nowadays non-existent Powder Bridge. The whole embankment mass is created by historic landfill and so the tunnelling and underground construction work was done under continual archaeological supervision.

 

The wings of both portals are made of monolithic concrete with juta fibre at the facing surface. The work included (besides the galleries and portals) also relocation and modification of the sewerage system, electrical connection, access road in the upper section and landscaping.

 

After the opening of the passage for public access it is possible to go from Klárov through the whole Jelení Ditch up to the Nový Svět while admiring unusual views of the Prague Castle.