Calculating the service life of bridges
Bochum’s engineers refine models
Utilising local conditions rather than default values
Comparison between the old and the new model: service life 14 times as long
The team headed by Dr Mark Alexander Ahrens and David Sanio from the Institute of Concrete Structures spent two and a half years studying the flyover “Pariser Straße” at the junction “Heerdter Dreieck”, in order to refine existing models for determining the service life of bridges. These models had been initially based on general assumptions that do not necessarily apply for each location in Germany, such as the number of heavy-duty vehicles crossing the bridge every day. The Bochum-based researchers wanted to know how much more precise the prognosis could become if they tailor-cut the model for one specific structure. The difference was considerable. According to the optimised arithmetical method, the service life would be 14 times as long as the one calculated using the previous model. One decisive factor was the fact that far fewer heavy-duty vehicles actually drive over the bridge than it has hitherto been assumed. In arithmetic terms, a heavy-duty vehicle with a load of 40 tons affects the structure in almost the same way as 100,000 passenger cars.
Long-term objective: the intelligent bridge
Following the tests carried out by the Institute of Concrete Structures and in collaboration with other institutes, a fundus of algorithms has been compiled which describe the various impacts affecting a structure. Traffic volume, temperature differences and construction materials, for example, play a role. Engineers can use that fundus like a modular kit to pick and choose the algorithms that are precisely suited for their individual application. The aim is to enable bridges to make these calculations automatically one day. An intelligent bridge could continuously monitor its own condition and raise the alarm once it detects signs of serious damage. However, engineers currently still lack the relevant long-term experience with the measurement technology.
Detailed article in the science magazine RUBIN
A detailed article with pictures can be found in the online magazine RUBIN, the RUB’s science magazine: http://rubin.rub.de/en/featured-topic-traffic/things-bridges-could-know-about-themselves Text and images in the download page are free to use for editorial purposes, provided the relevant copyright notice is included. You would like to receive a notification when new RUBIN articles are published? Then subscribe to our news feed at http://rubin.rub.de/feed/rubin-en.rss.