Improved remaining fatigue life of an orthotropic bridge deck: Combination of analyses, tests and measurements

Abstract

ABSTRACTPreviously to the renovation of a long steel highway bridge, built in 1969, the remaining fatigue life of the orthotropic bridge deck should be analysed. The bridge structure is a very slender box‐girder bridge with three spans (L = 120 + 210 + 82 = 412 m). The heavy traffic is very high, with approximately 1,2 million trucks per year in the busiest lane.This paper gives a summary of the comprehensive numerical analyses, combined with extensive measurements (traffic data, stress spectra at relevant details) and also fatigue tests on full scale test specimen. Fortunately, in front of the bridge an automatic lorry counting device was installed and therefore the numbers and types of lorries in each lane, on each day, within the last decade were well‐known.In addition, simplified models for the numerical simulation of the heavy traffic on the orthotropic bridge deck are shown, with comparison to field measurements of stress spectra under service conditions. These measurements were done to overcome the uncertainties in the simulation, e.g. overloads, specific lorry types, different positions within the lane and dynamic effects.Fatigue tests were done for the detail of the joint between the longitudinal ribs and the cross girder, with a non‐typical only one sided welded connection. For this detail also a very effective strengthening solution was developed and tested.