The concrete slab bridge on Balladelaan in the Netherlands was built in 1946. It is a cast-in-place concrete bridge with five spans that together form a statically indeterminate deck system. For this type of concrete bridge, shear failure often appears to be the critical failure mechanism, raising concerns about the structural capacity and remaining service life of the bridge. Additionally, the bridge has undergone several undocumented modifications over its lifetime, making it difficult to accurately assess its safety. To monitor this bridge and predict its structural capacity, 22 ultrasonic sensors, known as Smart Aggregates (SAs), and 16 temperature sensors were embedded in the bridge by drilling holes to track changes such as crack development, stress variations, and temperature fluctuations. This paper presents the initial phase measurements from the SAs and temperature sensors in the monitoring project. The main goals of this phase are (1) to ensure that the installed sensors function properly and (2) to establish a preliminary correlation between the measurements from the SAs and the temperature sensors.

Rail vibrations cause nuisance to people living near rail transport routes. Especially cargo transport is known to cause the highest vibration levels. The Netherlands have an intensively used railway network, forming one of the important cargo transport corridors from the Port of Rotterdam to other countries in Europe. With increasing use of the rail network, both in terms of the number of trains and higher speed of passenger trains, nuisance caused by rail vibrations is expected to increase as well. ProRail, the operator of the rail network in The Netherlands, has lauched the 'Innovatieagenda Bronaanpak Spoortrillingen' (IBS) research programme in order to develop more knowledge about rail vibrations and evaluate the effectiveness of potential mitigating measures. One of the project under this IBS research programme specifically addresses the contribution of train wheel defects to rail vibrations and their effects on nearby buildings. Witteveen+Bos is executing this project, working closely with ProRail and it's scientific partners. A measurement setup was developed optimized for linking ground vibrations to train wheels. This measurement setup has been operated at different locations along the Dutch rail network. Data analysis of the monitoring results has generated interesting insights into the characteristics of ground vibrations caused by train passages and the contribution wheel defects may have.