Exit branch of the Lahntal Bridge Lahnstein – Bad Ems

Time until renovation bridged

The exit branch of the Lahntal Bridge in Lahnstein connects Federal Highway B 42 with Federal Highway B 260 and is located on a steep slope on the north bank of the River Lahn. In order to find out for how long the exit, constructed in 1979, will still be usable at most, the State Office for Mobility commissioned KREBS+KIEFER to carry out a recalculation for the construction. This calculation was a challenging undertaking due to the exit's S shape with a very small curve radius.

The investigations in accordance with the guidelines for recalculations on existing road bridges revealed the need for a supplementary, external longitudinal prestressing. As an immediate measure against the sighs of fatigue that had been found in the coupling joints, the engineers suggested monitoring the cracks to check the width of the cracks in the coupling joints.


  • Recalculation of the load capacity in accordance with DIN
  • Expert report 102 and determination of the remaining life of the construction
  • Impact in accordance with DIN expert report 101 and in accordance with DIN 1072 (BKL 60/30)