Pont Adolphe Double-Decked Arch Bridge

The bridge Pont Adolphe in Luxembourg is a major construction designed by the French engineer P. Sejourne and built from 1899 to 1903. The bridge is made of two masonry arches with a span of 84.6 m on the central. At the time of the construction, the bridge held the world’s largest arch span for a masonry structure. Today the bridge is still one of the world’s most prominent masonry construction. In 1961 the bridge underwent some important refurbishment works to enlarge transversally the upper deck.

Aim of monitoring:

Over time cracks opened along the neutral axis of the main arches. To prevent significant damage to the bridge, perpendicular post-tensioning cables were installed. Thereafter the bridge was equipped with SOFO sensors to monitor the effectiveness of the strengthening (the main reason for the crack occurring) and to understand the real behavior of the bridge over the long term. Dynamic tests were also performed on this bridge, and SOFO sensors were monitored with the SOFO Dynamic Reading Unit. 

Main results:

The resulting measurements showed that no bending and no shear strain anomalies were noticed. Also, no relative rotations and no shear sliding between the blocks were detected. Only small average elongation changes were noticed, which seemed to be correlated to temperature variations due to day-night temperature fluctuations. During the analyzed period the structural behavior of the monitored area of the bridge is estimated to be correct and without anomalies. Dynamic test results are not available.