HBK provides reliable measurement results: GRASSL relies on this for infrastructure monitoring

A large part of the German transport infrastructure was built during the 1960s to 1980s. Many transport routes, especially in rail transport, are much older. Traffic volume has also significantly increased.

Therefore, these aged structures must be carefully examined to detect any possible defects at an early stage.

The experts at GRASSL engineering office first carry out model calculations as per the legal regulations by using the safety specifications of the applicable guidelines for recalculation.

The results allow them to make statements about a structure’s load-bearing capacity, its theoretical remaining service life, necessary upgrades, or the need to replace the structure with a new one.

Regardless of how meaningful and reliable the forecasts regarding a structure’s service life and the risk assessments based on model calculations are, in some cases, GRASSL recommends civil engineers to perform the long-term measurements of a structure stipulated in the guidelines, based on the results of model calculations, under real conditions.

The realistic test often shows that the actual remaining service life of a bridge is higher than the one previously calculated in the model, or a replacement structure that is recommended by model calculations can be disregarded since the structure can be safely used for a longer period through targeted upgrades.

This will result in significantly lower costs to customers and, often, fewer annoying traffic delays.

For the recalculations of the steel superstructures of the Graskeller and Mönkedammfleet viaducts of Hamburger Hochbahn, a team of the GRASSL engineering office carries out long-term measurements for their client. HBK Service & Support provides GRASSL’s engineers with support through a customized monitoring solution and associated services.

GRASSL is testing the Graskeller and Mönkedammfleet viaducts that were built in 1911 on Hamburger Hochbahn AG’s behalf. This part of the Hanseatic city metro is a protected cultural site, and its restoration will begin from 202. The long-term measurements of the structure performed by GRASSL and HBK provide information about the required measures.

A particular challenge is that the superstructures of the viaducts that are to be monitored consist of components with different cross-sections, which were not welded but riveted.

Therefore, determining the realistic mechanical stresses for the calculations is extremely complex.

Thus, GRASSL carefully determined the relevant measuring points of an extensive monitoring concept, which are necessary to measure the actual stress affecting the bridge. Based on this data, the structural health-monitoring experts from HBK selected the technology components required for measurement.