RAILWAY BRIDGE CROSSING THE RIVER WÄTERN

Initial Situation

The existing railway crossing is a vaulted 6 span bridge consisting of brickwork and has been erected in 1867. The building has already been repaired and overhauled several times. The building transfers the important and highly frequented route from Wunstorf to Bremerhaven crossing the Wätern and represents an important connection to the international port Bremerhaven.

The vaults of the building are marked by damages in the brickwork and significant cracks. After 150 years the building has reached its service life. For this reason a new bridge will be erected next to the existing old bridge.

Goal

To determine significant changes in the existing building during the works at the foundation in time and to take the necessary steps if needed a monitoring system with a three-step warning and alert system has been installed to observe the building process of the foundation.

In selected areas of the bridge the settlements will be observed with an electronic hose leveling. The development of the cracks in the arches as well as the deformation of the front walls will be acquired by laser distance sensors.

All measurements will be collected in a centralized data system and can be retrieved by those who are involved over an online-portal at any time. So, deformations because of the building process can be noticed and rated very quickly by the building inspection, the project management and the facility operator. Dangers for the building resulting from settlements, developments of cracks and tilting will be reported by the alarm and the limit value before they will be visible.

During the pile driving process for the new bridge measurements regarding concussion will be carried out at the vault piers with tri-axial velocity transducers.

In the South an embankment is affiliated with the tractrix curve. Regarding the ground works settlements at the existing embankment can’t be ruled out. To ensure safe rail operations the behavior of the embankment during the building period will be observed with a settlement monitoring using an electronic hose leveling.

Width: 
9,00 m
Height: 
5,00 m
Length: 
98,00 m

Construction:
Six-span vaulted bridge

Location:
Nearby Verden (Aller) on the route 1740 Wunstorf - Bremerhaven Seaport in km 85.024

Length:
98,2 m

Year of Construction:
1867

Spans:
6 x 16.36 m

Activities Marx Krontal:
Development and tendering of a structural monitoring, determination of warning values and limits, evaluation of the monitoring results

Monitoring:
2012 until the end of 2013