Browsing by Author "Meyer, Markus Willem"

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    The characterization of the dynamic interaction between highway bridges and long, multi-trailer heavy vehicles
    (Stellenbosch : Stellenbosch University, 2022-04) Meyer, Markus Willem; Lenner, Roman; De Koker, Nico; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
    ENGLISH ABSTRACT: Around the world, many countries are experiencing an increase in demand for freight to be transported by road. One solution is to introduce larger heavy vehicles, which are capable of transporting more freight. These vehicles have more trailers, more axles and are longer and heavier than existing heavy vehicle traffic. All these factors have an important influence on the dynamic amplification between the vehicle and bridge. This contribution investigates the dynamic behaviour of long, multi-trailer vehicles, specifically the B-Double vehicles, when crossing short to medium span bridges. The dynamic behaviour of these larger vehicles is compared to the well-known single articulated vehicles which are currently operating in many countries around the world. The effect of axle groups and their spacing on dynamic amplification is explored in depth to support the finding that the time of entry of axle groups on an excited bridge is key to the explanation of dynamic response. The relationship between midspan accelerations and dynamic amplification is introduced and explored extensively for further validation of the findings presented. There is an indication that the commonly accepted inverse relationship between the high static load and observed low dynamic amplification is not generally true when comparing vehicles of different axle configurations. The number of axles, along with inter-axle spacing matching the natural frequency of the bridge, is of substantial relevance to the dynamic response, yielding in some cases higher dynamic amplification of high static loads. It is shown that due to the latter, the significantly heavier vehicles can induce higher dynamic amplification on medium span bridges than some lighter vehicles with different axle configurations. Furthermore, a dynamic load signature is developed which defines the typical dynamic loads induced by B-Double vehicles at midspan for short to medium span bridges. It is shown that the dynamic loads can be defined as a function of the first natural frequency of the bridge and the midspan accelerations. Ultimately, a new method of estimating dynamic amplification factors by implementing a dynamic load signature function in addition to strain and acceleration measurements, is proposed.