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Estimating traffic‐induced vibrations of road bridges prior to concreting works – Creating a meta‐model for preliminary estimation of the risk of early‐age concrete being negatively affected during its hardening by ongoing traffic The interaction between the bridge and the vehicles passing over it is governed by very complex interrelationships, effects of which are difficult to predict. When construction works on existing concrete bridges take place, vibrations caused by ongoing traffic pose a potential risk for the early‐age concrete, which may be being negatively affected during its hardening process. But especially in the course of the planning of construction processes and procedures, a preliminary estimate of potential risk would be helpful. For this reason, large‐scale computation series based on calculation models of entire bridge populations was executed. The aim was to estimate the traffic‐induced vibrations of slab and T‐beam bridges in common configurations to be able to take appropriate steps in planning of construction works and protect the young concrete in its critical hardening phase. The bridge vibrations were calculated by transient FE‐simulation for a large number of truck passages, while bridge properties such as span, slenderness, etc. on one hand, and crossing parameters such as road surface and driving speed and lane on the other hand, were varied. The consideration of individual parameters turned out to be insufficient, therefore a meta‐model in the form of simple equations was formed based on the large data set created. The meta‐model combines the influence of several parameters and provides an initial estimate of the expected vibration amplitudes, which supports decision‐making in the planning of necessary measures. [ABSTRACT FROM AUTHOR]

Traffic vibrations during concreting work on existing road bridges – Vibration prognosis for the assessment of construction stages in course of the newly constructed highway bridge A 23 – Hochstraße Inzersdorf The construction works on existing bridges must often take place without traffic interruptions. During bridge‐widening works or closing of construction joints, the hardening concrete is exposed to traffic‐induced vibrations. This can damage the material permanently, depending on the amplitude of vibration velocity. This study investigates factors that influence amplitude of traffic‐induced vibrations of a slab bridge on the A 23 motorway in Vienna, which was rebuilt in several construction phases. Transient dynamic simulations were used to analyze the influence of the driving speed, vehicle mass and road evenness. Measured road profile data, which were collected by high‐resolution laser scanning of the road surface, were used in FEM simulations. Bridge resonance properties were verified by vibration measurements. While bridge deflections and strains are mainly influenced by vehicle mass, the vibration velocities are primarily determined by the road profile. The predicted vibration velocities were compared to a limit value taken from the literature, the observance of which should not lead to any impairment of the young concrete. The results served as a decision basis for the selection of suitable measures during the critical hardening phase of the concrete in the connection joint. [ABSTRACT FROM AUTHOR]