Mott MacDonald is working in partnership with SUDOP to repair the viaduct over the right branch of the river.
- Czech National Bank’s fourth circulation of Bridges cycle gold coins depicts the Negrelli viaduct.
- The development was initiated to continue the North state trunk route from Prague to Dresden.
- The viaduct stretches 7.60m wide and incorporates 90 arches.
Reconstruction and remediation
This project involves addressing all structural damage to the viaduct, as well as its railway superstructure, signalling, telecommunications, electrical equipment and overhead lines. The restoration is closely linked with the ‘Modernisation of Prague, Kladno’ project, which is enabling the implementation of a several number of the works.
The viaduct’s bearing and non-bearing structures have localised degradations due to water leakage as well as the effects of climate change. The drainage system is broken and new waterproofing is required along the entire length of the crossing. Stone cornice boards also need replacing.
An underwater survey found other defects – for example, missing mortar in the backfilled stone piers in the river and its masonry base. As a result, a sealed tank has been proposed to dry matching walls for the grouting of the pier foundation. The new steel railing pattern, 1933, has been recommended as it agrees with the full project concept. Abutments will be used to support the stone bridge railing. Following the remediation of the spandrel walls, a sub-ballast will be placed over the arches and then a reinforced concrete slab will be positioned on top of this to act as a base and to anchor crown stones. Existing cornice stones will be left to enable the protrusion, cut away and anchoring to the decks.
Our team in Prague is responsible for restoring the Negrelli Viaduct over the right branch of the river. The supporting structure of the existing bridge spans a length of 107.7m and consists of three segmental granite arches. Each arch spans 29.39m between the abutments on both banks. The abutments and stone piers are both 12.1m in height. The original width of the deck is 9.8m and extends to 10.5m.
Value and benefits
Our contribution on this project provides further evidence of our local team’s extensive expertise and ability to add value to restoring historical sites – extending on their role in developing plans to repair and maintain one of Prague’s important ancient monuments, the Charles Bridge.