Now showing 1 - 10 of 18
  • Publication
    Dynamic Load Allowance
    Chapter 4 provides a good explanation of the current state-of-the-art for the influence of dynamics on bridge traffic loading. It starts with an explanation of the concepts and a review of the various definitions used in the field, such as Dynamic Amplification factor and Impact Factor. It looks at how some of the main codes of practice in the world treat dynamics. A considerable portion of the chapter deals with the statistics of dynamic amplification. It is noted that the biggest dynamic amplifications tend to occur for light vehicle loading events. A statistical approach addresses this issue and provides a more appropriate allowance for dynamics which is called Assessment Dynamic Ratio. The influence of road surface roughness is considered and the implications of a local irregularity or pothole, as sometimes happens near the end joints. A number of field measurement campaigns of dynamic amplification are reported from various countries. These largely support the findings of the numerical studies.
      153
  • 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
      1035
  • Publication
    Weighing-In-Motion of Axles and Vehicles for Europe (WAVE) WP1.2: Bridge WIM Systems
    The objective of the WAVE project was to effect a significant step forward for those responsible  for road networks, through the following actions: Improve the capacity of conventional WIM systems to accurately estimate static loads from measurements of dynamic impact forces applied by axles, through use of arrays of sensors whose combined results can allow for the dynamic interaction between vehicle and pavement. Develop and improve the functioning and accuracy of bridge-based WIM systems through more sophisticated vehicle/bridge interaction modelling and data processing. Develop common data structures, formats and quality assurance procedures to facilitate the exchange and comparison of WIM data throughout Europe, to increase confidence in such  data and to provide reliable management information to decision makers. Perform tests of WIM systems to assess their durability and performance in various climatic conditions, particularly in cold regions where pavements deform and are weaker during the thaw and sensors are susceptible to studded tyres and de-icing salt. Develop standardised calibration methods  and  procedures  by improving  existing methods and extending their applicability to all European climates and types of WIM system. Develop and implement a new WIM technology,  based on an innovative fibre optic sensor  which has considerable potential in terms of quality and the extent of information provided and its insensitivity to harsh climatic conditions.This project constituted a strategic policy initiative to confirm the Europe's leadership in WIM. It led to the development of new technologies such as advanced multiple sensor and bridge WIM systems, a quality assurance procedure to be implemented in a pan-European database, data about the behaviour of WIM systems in harsh environments, an improvement in calibration procedures and  the development of a new European optic-fibre WIM technology. That will help road and transport decision makers.
      680
  • Publication
    A Review of Road Structure Data in Six European Countries
    The European Union has expanded significantly in recent years. Sustainable trade within the Union leading to economic growth to the benefit of the 'old' and 'new' member states is thus extremely important. The road infrastructure is strategic and vital to such development since an uneven transport infrastructure, in terms of capacity and condition, has the potential to reinforce uneven development trends and hinder economic convergence of old and new member states. Significantly, in the decades since their design and construction, loading conditions have significantly changed for many major highway infrastructure elements/networks due primarily to increased freight volumes and vehicle sizes. This coupled with the gradual deterioration of a significant number of highway structures, due to their age, and the absence of a pan-European assessment framework can be expected to affect the smooth functioning of the infrastructure in its as-built condition, through increased periods of reduced flow due to planned and unplanned interventions for repair/rehabilitation. This paper reports the findings of a survey regarding the current status of the highway infrastructure elements in six countries within the European Union as reported by the owners/operators. The countries surveyed include a cross section of ‘existing’ older countries and ‘new’ accession countries. The current situations for bridges, culverts, tunnels and retaining walls are reported along with their potential replacement costs. The findings act as a departure point for further studies in support of a Centralized and/or Synchronised EU approach to Infrastructure Maintenance Management. Information in the form presented in this paper is central to any future decision making frameworks in terms of trade route choice and operations, monetary investment, optimized maintenance, management and rehabilitation of the built infrastructure and the economic integration of the newly joined member states.
      769
  • Publication
    Using statistical analysis of an acceleration-based bridge weigh-in-motion system for damage detection
    This paper develops a novel method of bridge damage detection using statistical analysis of data from an acceleration-based bridge weigh-in-motion (BWIM) system. Bridge dynamic analysis using a vehicle-bridge interaction model is carried out to obtain bridge accelerations, and the BWIM concept is applied to infer the vehicle axle weights. A large volume of traffic data tends to remain consistent (e.g., most frequent gross vehicle weight (GVW) of 3-axle trucks); therefore, the statistical properties of inferred vehicle weights are used to develop a bridge damage detection technique. Global change of bridge stiffness due to a change in the elastic modulus of concrete is used as a proxy of bridge damage. This approach has the advantage of overcoming the variability in acceleration signals due to the wide variety of source excitations/vehicles-data from a large number of different vehicles can be easily combined in the form of inferred vehicle weight. One year of experimental data from a short-span reinforced concrete bridge in Slovenia is used to assess the effectiveness of the new approach. Although the acceleration-based BWIM system is inaccurate for finding vehicle axle-weights, it is found to be effective in detecting damage using statistical analysis. It is shown through simulation as well as by experimental analysis that a significant change in the statistical properties of the inferred BWIM data results from changes in the bridge condition.
      52Scopus© Citations 21
  • Publication
    EU FP6 - ARCHES Deliverable D10: Recommendations on dynamic amplification allowance
    The ARCHES (Assessment and Rehabilitation of Central European Highway Structures) project (2006-09) involved partners from Belgium, Croatia, Czech Republic, Ireland, Italy, Poland, Slovenia, Spain, Switzerland and The Netherlands. The overall goal of the project is to reduce any gaps in the standard of highway infrastructure between Central and Eastern European Countries, particularly New Member States and the rest of the EU. Deliverable D10 is within WP2: optimise the use of existing infrastructure through better safety assessment and monitoring procedures which will avoid interventions, i.e., avoid unnecessary replacing or improving structures that are in fact perfectly safe. In particular, D10 provides a more realistic site-specific dynamic allowance for traffic loading than those genral values recommended in bridge codes.Correct evaluation of the behaviour of highway bridges under heavy traffic loading is extremely important both for the enhancement of design techniques, and also for the assessment of existing infrastructure. It is widely accepted that shortfalls exist in the determination of the traffic load which the bridge may be required to support during its expected lifetime due to inadequate consideration of amongst other factors, the dynamic interaction between the bridge structure and the heavy vehicles crossing it. Since it is the overall objective of this deliverable to combine lifetime static load effect values, with realistic dynamic amplification factors (to obtain an overall total lifetime load effect) there are two distinct parts:1) The calculation of bridge static load effect due to site-specific traffic flow, which is discussed in subtask 2.1.1 (Deliverable D08) along with the resultant assessment of bridge lifetime static load effect, and the selection of those loading events that are deemed critical (statically).Examples on how to determine these bridge traffic load models using Weigh-In-Motion (WIM) data and their configuration when using data from Central European countries are provided in subtask 2.1.1 on bridge traffic load monitoring. This subtask has also compared results between data from Western and Central European countries.2) Deliverable D10 focuses on the assessment of the levels of dynamic interaction occurring between a bridge and its associated vehicular traffic. This analysis incorporates a review of those recommendations given in current design/assessment codes for dynamic allowance.Then, the procedure to obtain a site-specific dynamic amplification factor using theoretical simulations and available experimental data is described. Some specific issues concerning the dynamic allowance associated to: (a) deteriorated bridges; (b) pre-existing bridge vibrations; (c) maximum total effects developing in sections different from midspan, (d) the existence of a bump prior to the bridge, or (e) critical loading cases such as cranes, are also discussed. Finally,general recommendations on dynamic allowance are provided.
      164
  • Publication
    EU FP6 - ARCHES Deliverable D08: Recommendations on the use of results of monitoring on bridge safety assessment and maintenance
    The ARCHES, which is the Specific Targeted Research Project, was planned in response to the European Commission’s call for proposals 3B, addressing Topic 2.6 ‘Design and manufacture of new construction concepts’ of objective ‘Sustainable Surface Transport’ under the Thematic priority 1.6 ‘Sustainable Development, Global Change and Ecosystems’ of the GROWTH part of the Sixth Framework Programme. The contract was signed by the Commission on the 25th of October 2006. Project commencement date was the 1st of September 2006 and the duration of the project is 36 months.
      184
  • 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.
      3472Scopus© Citations 88
  • Publication
    Recommendations on dynamic amplification allowance
    (European Commission, 2009-08) ;
    The ARCHES (Assessment and Rehabilitation of Central European Highway Structures) project (2006-09) involved partners from Belgium, Croatia, Czech Republic, Ireland, Italy, Poland, Slovenia, Spain, Switzerland and The Netherlands. The overall goal of the project is to reduce any gaps in the standard of highway infrastructure between Central and Eastern European Countries, particularly New Member States and the rest of the EU. Deliverable D10 is within WP2: optimise the use of existing infrastructure through better safety assessment and monitoring procedures which will avoid interventions, i.e., avoid unnecessary replacing or improving structures that are in fact perfectly safe. In particular, D10 provides a more realistic site-specific dynamic allowance for traffic loading than those genral values recommended in bridge codes.Correct evaluation of the behaviour of highway bridges under heavy traffic loading is extremely important both for the enhancement of design techniques, and also for the assessment of existing infrastructure. It is widely accepted that shortfalls exist in the determination of the traffic load which the bridge may be required to support during its expected lifetime due to inadequate consideration of amongst other factors, the dynamic interaction between the bridge structure and the heavy vehicles crossing it. Since it is the overall objective of this deliverable to combine lifetime static load effect values, with realistic dynamic amplification factors (to obtain an overall total lifetime load effect) there are two distinct parts:1) The calculation of bridge static load effect due to site-specific traffic flow, which is discussed in subtask 2.1.1 (Deliverable D08) along with the resultant assessment of bridge lifetime static load effect, and the selection of those loading events that are deemed critical (statically).Examples on how to determine these bridge traffic load models using Weigh-In-Motion (WIM) data and their configuration when using data from Central European countries are provided in subtask 2.1.1 on bridge traffic load monitoring. This subtask has also compared results between data from Western and Central European countries.2) Deliverable D10 focuses on the assessment of the levels of dynamic interaction occurring between a bridge and its associated vehicular traffic. This analysis incorporates a review of those recommendations given in current design/assessment codes for dynamic allowance.Then, the procedure to obtain a site-specific dynamic amplification factor using theoretical simulations and available experimental data is described. Some specific issues concerning the dynamic allowance associated to: (a) deteriorated bridges; (b) pre-existing bridge vibrations; (c) maximum total effects developing in sections different from midspan, (d) the existence of a bump prior to the bridge, or (e) critical loading cases such as cranes, are also discussed. Finally,general recommendations on dynamic allowance are provided.
      346
  • Publication
    Characteristic dynamic traffic load effects in bridges
    When formulating an approach to assess bridge traffic loading with allowance for Vehicle-Bridge Interaction (VBI), a trade-off is necessary between the limited accuracy and computational demands of numerical models and the limited time periods for which experimental data is available. Numerical modelling can simulate sufficient numbers of loading scenarios to determine characteristic total load effects, including an allowance for VBI. However, simulating VBI for years of traffic is computationally expensive, often excessively so. Furthermore, there are a great many uncertainties associated with numerical models such as the road surface profile and the model parameter values (e.g., spring stiffnesses) for the heavy vehicle fleet. On site measurement of total load effect, including the influence of VBI, overcomes many of these uncertainties as measurements are the result of actual loading scenarios as they occur on the bridge. However, it is often impractical to monitor bridges for extended periods of time which raises questions about the accuracy of calculated characteristic load effects. Soft Load Testing, as opposed to Proof Load or Diagnostic Load Testing, is the direct measurement of load effects on bridges subject to random traffic. This paper considers the influence of measurement periods on the accuracy of soft load testing predictions of characteristic load effects, including VBI, for bridges with two lanes of opposing traffic. It concludes that, even for relatively short time periods, the estimates are reasonably accurate and tend to be conservative. Provided the data is representative, Soft Load Testing is shown to be a useful tool for calculating characteristic total load effect.
      1310Scopus© Citations 56