REPLACEMENT OF THE LUCKENBERGER BRIDGE ACROSS THE HAVEL IN BRANDENBURG

The new ‘Luckenberger Bridge’ in the city of Brandenburg carries both road and tramway traffic. A king post truss structure with a total length of 56.50 m and a width of 12.50 m was chosen in order to reduce the construction depth as much as possible to a value of 0.67 m due to restraints from shipping clearance below and tram profile above. Horizontal displacements from horizontal thrust of the inclined leg foundations on poor soil conditions would have had a most detrimental effect on the forces in the structure. For this reason, a sophisticated construction process was chosen. The calculated normal forces in the superstructure were introduced with jacks in an original gap in the middle of the superstructure thus allowing the horizontal displacements to occur without effects on the forces in the structure. The jacks were subsequently replaced by steel struts of equivalent length before casting the gap. The durability of the structure and the limitation of deflections were of great importance. This was achieved by using high strength concrete for the legs and the superstructure with moderate posttensioning. The design strength was B 85 corresponding to the ‘DafStb-Richtlinie fur hochfesten Beton’. The raking legs were built in the casting yard of a nearby concrete company as precast concrete units, the superstructure was cast in two divisions of 180 m³ concrete each. The concrete mix had to be calibrated to achieve good workability and to allow the final finish of the top in slope. ‘Polycarboxylate-ether’ was successfully used as an admixture. To minimize the residual stress the concrete mix were calibrated to achieve the design strength at the same time. The ‘Luckenberger Bridge’ was awarded with the Structural Engineering Prize 2002 of the Federal State of Brandenburg.

• INTRODUCTION

• DESIGN OF THE NEW BRIDGE

• HIGH STRENGTH CONCRETE

• CONSTRUCTION

• MONITORING DURING SERVICE

• SUMMARY

• ACKNOWLEDGEMENTS

• REFERENCES