Now showing 1 - 5 of 5
  • Publication
    Transverse variation of dynamic effects on beam-and-slab medium span bridges
    The common approach used to quantify bridge critical load cases is by definition conservative, as the effect of Dynamics is generalised. As a result a number of the site specific and load specific dynamic characteristics are neglected, and the transverse distribution of dynamic amplification across the bridge section also lacks consideration. In this paper, both issues are discussed using simulations of the passage of heavy traffic over an experimentally validated beam-and-slab bridge model. Stress variations across the bridge have been calculated for a number of scenarios involving different combinations of heavy trucks with varying velocities and directions. Results show a significant difference in transverse distribution of load effects and how certain longitudinal beams are more prone to dynamic excitation.
  • Publication
    The effect of vehicle velocity on the dynamic amplification of two vehicles crossing a simply supported bridge
    (American Society of Civil Engineering (ASCE), 2006-03) ;
    The effect of multiple vehicles on a bridge’s dynamic amplification is a complex problem. Previously authors have examined multiple vehicle presence by constructing elaborate finite element models or undertaking field tests. Although both these methods give valuable information regarding the magnitude of dynamic amplification, the results tend to be site-specific and give limited insight into how large amplifications occur. This paper examines the dynamic amplification factor of a simply supported bridge being crossed by two loads traveling in both the same and opposing directions. Simple numerical point load models are used to determine the critical load velocities and load positions that result in high amplifications. An experimentally validated finite element model is used to examine the applicability of the conclusions to real bridge/vehicle systems.
      951Scopus© Citations 34
  • Publication
    The influence of speed on the dynamic amplification of two loads crossing a simply supported bridge
    It is possible to use statistical data for the determination of traffic load models for the design of bridges. For existing bridges, traffic simulations based on measured traffic data, can provide a more accurate prediction of the characteristic load effect for assessment purposes. However, this procedure only provides the characteristic static loading or load effect. The total static-plus-dynamic load is often estimated based on conservative factors due to the high degree of uncertainty involved in the dynamic interaction between traffic, road profile and bridge. This paper aims to reduce this uncertainty by using simple dynamic models to obtain an understanding of the speeds and axle spacings that cause the highest dynamic amplifications.
  • Publication
    Impact factors on medium span bridges due to multiple vehicle presence
    The Dynamic Amplification Factor for Bridges is of major concern in both their design and assessment. Research to date has focused on the single truck event. However, in many bridges the critical loading case is that of multiple truck presence on the deck. To accurately determine the dynamic amplification factor it is necessary to examine the effects of multiple trucks traversing a bridge. Experiments in Slovenia were carried out to examine the dynamic amplification factor for single and two truck events. Numerical models were constructed and validated from these experiments. These models were then used to compare the dynamic amplification factors produced from both single and multiple trucks crossing the bridge at various speeds. Important conclusions are drawn for bridge design and assessment purposes.
  • Publication
    The effect of vehicle velocity on the dynamic amplification of a vehicle crossing a simply supported bridge
    (American Society of Civil Engineering (ASCE), 2006-03) ; ;
    Many authors, using both experimental tests and complex numerical models, have examined the effect of vehicle velocity on a highway bridge’s dynamic amplification. Although these tests and models give valuable quantitative information on dynamic amplification, they give little insight into how amplification is affected by individual vehicle/bridge parameters. This paper uses relatively simple numerical models to investigate the effect of vehicle velocity on a bridge’s dynamic amplification. A single vehicle crossing a simply supported bridge is modeled as a constant point force. A set of critical velocities are determined associated with peaks of dynamic amplification for all beams. The reasons for these large amplifications are discussed. A more complex finite element model, validated with field tests, is used to test the applicability of the conclusions obtained from the simple models to a realistic bridge/vehicle system.
      3353Scopus© Citations 79