Bridge structures are being renovated and rebuilt

At its meeting today, the city council decided to repair the Guerickestraße bridge and to replace the Dorfstraße Mittelbach bridge with a new structure.

Guerickestraße bridge

The Guerickestraße bridge is an arched bridge. The condition report from 2021 confirms some damage to the structure. For example, moisture penetration of the masonry has led to a reduced load-bearing capacity. Missing or non-functioning bridge seals are the cause of surface water, including de-icing salts, being able to penetrate the structure.
The inspection of the structure has shown that the masonry is still stable in terms of the stone and mortar material and that the basic structure of the structure is therefore well preserved, so that the repair of the structure is now possible at a considerably lower time and cost.

The bridge has a total length of approx. 8.50 metres and a clear width of approx. 7.20 metres. It is 18.85 metres wide between the railings. The smallest clear height is approx. 4.10 metres. The asphalt road, including the paved gutters, is 5 metres wide and the paved walkways on both sides are between 4.20 and 4.80 metres wide. There are also green areas outside the arch. The vaulted arch, as well as the end and wing walls, are made of hammer-straight layered masonry.

The backfill and backfill of the structure will be removed for the renovation. This will expose the arch and the neighbouring wing walls. The top of the arch is cleaned of loose building material. The surface water is drained via the longitudinal and transverse slopes in the road and pavements, with discharge into the corresponding road drains. A base pipe is routed through the structure approximately every 4 metres and the water is drained into the Kappelbach.

The construction period is estimated to be six months and the work will not be carried out in winter. Work is expected to start in the first quarter of 2024 and the planned costs total around 660,000 euros

As the bridge is the only major access route for the residential area behind it from the south, the construction work will be carried out in such a way that traffic can continue to drive over the structure on one side. The bridge will be closed on one side with traffic lights. A separate footpath is available for pedestrians.

Mittelbach village road bridge structure - replacement construction

The village stream in Mittelbach flows under the existing bridge structure. It flows in a longer section in a culvert or vault. The bridge structure to be replaced is located on a property owned by the city of Chemnitz in the section of Dorfstraße Mittelbach at house numbers 6 and 12 and forms a public access road to the properties house numbers 8 and 10.

The exact year of construction of the bridge is not known. The last structural inspection resulted in the worst condition rating of 4.0. The increased traffic load, the advanced age of the culvert and the associated material fatigue of all construction materials and components have caused damage such as Transverse cracks in the vault wall, concrete breakouts in the vault wall, defective pipe connections as well as scouring and damage in the area of the watercourse bed and in the bed area. The most serious damage is the cracks through the vault wall. If these tear completely through, a collapse of the arch cannot be ruled out.

For this reason, the bridge must be replaced by a new structure. The structure will be completely demolished up to the level of the base of the structure. The foundation of the existing bridge can remain in the ground and will be used in part as a foundation for the new structure. A reinforced concrete frame open at the bottom is planned for the new structure.

Construction will take around four to five months, weather permitting. The costs will total around 475,000 euros.

The new replacement can only be built with a full road closure. A diversion route is available to divert traffic. A footpath will be provided for pedestrians. Access to the properties will be guaranteed.