The assessment of the existing road bridges as a part of bridge management networks has been a subject of several European research projects and actions in the last few decades. Bridge management includes a series of activities, interconnected in order to achieve optimal balancing of required costs, potential risks and overall bridge performance. This paper discusses a valuable link between a specific indicator (traffic load information calculated using Bridge Weigh-in-Motion measurement data) and the corresponding structural performance (reliability of existing bridge). It is shown that implementation of weigh-in-motion measurements in the probabilistic assessment of existing road bridges can reveal hidden bridge reserves and predict bridge reliability development over the required lifetime. Consequently, such approach can yield an unrestricted use of the bridge over a much longer remaining service life. Broader advantages lie in an improved road network management, road bridges in particular, and in a more sustainable development of infrastructure network and greater satisfaction of road users and owners.
COBISS.SI-ID: 2340455
This paper deals with accuracy and long-term stability of bridge weigh-in-motion (B-WIM) systems. Research focused on four improvements, developed within two research projects financed by the European Commission. These improvements have increased accuracy of the results for four classes according to the European WIM specifications. The novel axle detection method recommends alternative locations to acquire strain responses under the moving vehicles, which provide reliable axle information without the need to install axle detectors in the carriageway. The new algorithm for calculating experimental influence lines combines the individual influence lines, generated from the responses of vehicles from the traffic flow, to obtain a robust solution that does not depend on the type of the vehicle. The third development adjusts the sensor factors to account for measurement errors on concrete structures, especially those resulted from hidden cracks. Finally, the effects of varying temperature and vehicle velocities on the WIM results were studied and their influences mitigated, to increase long-term stability of B-WIM results. All improvements were validated using long-term B-WIM measurements collected on four different bridges.
COBISS.SI-ID: 2338663
The dynamic component of bridge traffic loading is commonly taken into account with a Dynamic Amplification Factor (DAF) % the ratio between the dynamic and static load effects on a bridge. In the design codes, this factor is generally higher (more conservative) than in reality. Bridge weigh-in-motion systems use an existing instrumented bridge or culvert to weigh all crossing vehicles at highway speeds. A new method of obtaining DAF experimentally, using bridge weigh-in-motion (B-WIM) measurements, will be presented in this paper. Data from several bridge sites has been used to evaluate DAF with the proposed method. The results agree with numerical simulations and experiments performed in the ARCHES project: dynamic amplification decreases as static loading increases. The reason is that the extreme loading events, which include several heavy trucks with many axles, induce far smaller dynamic amplification than the lighter individual vehicles. This point is extremely important for assessment of bridges.
COBISS.SI-ID: 2273383
Prediction of traffic loads on bridges is a challenging task, because they vary with time and location. Development of weigh-in-motion (WIM) technology has mitigated this issue as WIM systems acquire reliable and unbiased data of all heavy duty vehicles in free-flow traffic (axle loads and spacings, gross weights, velocities). This data are vital for assessment of realistic structural safety of bridges. In general, two different types of WIM systems exist that are installed in pavements or on bridges. Both attempt to calculate the best approximation of the axle loads and gross weights of the crossing vehicles. This paper presents the background of the conventional bridge WIM algorithm and the results these systems can provide to improve bridge assessment: load effects, influence lines, load distribution factors and dynamic amplification factors.
COBISS.SI-ID: 2330215
The Conference of European Directors of Roads (CEDR) has in recent years drawn eight tenders for applied research and development (R&D) projects, whose main objectives were to bring together the best expertise from across Europe to develop useful method ologies and to prepare guidelines and recommendations in the various fields of administrations activities, and to avoid duplication of similar research wor k that has been in the past performed in the individual member countries. Unlike the more basic research, funded by the European Commission under the Framework Programmes, the CEDRʼs calls always focus on the areas of the road administrations that are important for their operation. Most often the trans-national R&D program mes have asked for results in the areas of asset manage ment, traffic safety and environment, particularly related to the impact of climate change on the development and maintenance of road assets. Among the approximately fifty projects funded so far there were only a few dedicated to bridges. Two on the topic of effective management of bridges, with considerable contribution of Slovenian partners, are presented in this paper.
COBISS.SI-ID: 2272615