Now showing 1 - 2 of 2
  • Publication
    Comparison of Two Independently Developed Bridge Weigh-In-Motion Systems
    (Inderscience Enterprises, 1999) ; ;
    This paper describes an experiment in which 2 independently developed bridge weigh-in-motion (WIM) systems are tested and compared, both for accuracy and durability. The systems, an Irish prototype still under development and a commercially available American system, were tested on a bridge in Slovenia. 11 statically pre-weighted trucks were each driven over the bridge several times at a range of typical highway speeds. Accuracies for axle and gross vehicle weights are presented within the framework of the draft European WIM specification, and the bias which can be introduced by the selection of a calibration truck is demonstrated. Performance factors relating to durability are also discussed with particular emphasis on axle detectors
  • Publication
    The Influence of Correclation on the Extreme Traffic Loading of Bridges
    Accurate traffic loading models based on measured data are essential for the accurate assessment of existing bridges. There are well-established methods for the Monte Carlo simulation of single lanes of traffic, and this can easily be extended to model the loading on bridges with two independent streams of traffic in opposing directions. However, a typical highway bridge will have multiple lanes in the same direction, and various types of correlation are evident in measured traffic. This paper analyses traffic patterns using multi-lane WIM data collected at two European sites. It describes an approach to the Monte Carlo simulation of this traffic which applies variable bandwidth kernel density estimators to empirical traffic patterns of vehicle weights, gaps and speeds. This method provides a good match with measured data for multi-truck bridge loading events, and it is shown that correlation has a small but significant effect on lifetime maximum load effects.