Search

The paper presents the main results of the development project "Digitalization of monitoring the condition of bridge structures on highways and expressways in the Republic of Slovenia". Within the project, test cases of the digitalized inspection method were carried out on three different concrete bridges. To enable validation of digitalization, a traditional and digital inspections for all three bridges have been conducted, focusing on the three important types of reinforced concrete bridges damages: delamination, cracks and reinforcement corrosion. The comparison of the results has shown that digital inspection can already strongly support bridge inspections, especially during detailed inspections, as it can, to some extent, completely replace the time‐consuming damage mapping. In addition, the analyses show that, already today, digital inspection is often economically justifiable. [ABSTRACT FROM AUTHOR]

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 more conservative than in reality. Recently a new method of calculation of this factor had been developed. Data from 15 different bridges have been analysed since then and this paper presents the results of the analyses. The background for Bridge Weigh-in-Motion is given, and the most recent method for DAF calculation is described. The sites from which the data originated are presented, and the selection of data discussed. The results of the analyses are presented and discussed and some examples of DAF calculations are shown. Data from the considered sites have invariably demonstrated a DAF decrease with increasing axle load. This is a significant result, especially for assessment of existing structures, since it is beneficial to use measured structural parameters to optimise structural analysis. [ABSTRACT FROM AUTHOR]

The dynamic component of bridge traffic loading is commonly taken into account with a Dynamic Amplification Factor (DAF) – the ratio between the maximum dynamic and static load effects on a bridge. In the design codes, this factor is generally higher than in reality. While this is fine for new bridges that must account for various risks during their life-time, it imposes unnecessary conservativism into assessment of the existing well defined bridges. Therefore, analysis of existing bridges should apply more realistic DAF values. One way of obtaining them experimentally is by bridge weigh-in-motion (B-WIM) measurements, which use an existing instrumented bridge or culvert to weigh all crossing vehicles at highway speeds. The B-WIM system had been equipped with two methods of obtaining an approximation to the static response of the. The first method uses the sum of influence lines. This method relies on accurate axle identification, the failure of which can have a large influence on the DAF value. The other method uses a pre-determined low-pass filter to remove the dynamic component of the measured signal; however an expert is needed to set the filter parameters. A new approach that tries to eliminate these two drawbacks has been developed. In this approach the parameters for the filter are determined automatically by fitting the filtered response to the sum of the influence lines. The measurement of DAF on a typical bridge site agrees with experiments performed in the ARCHES [1] project: dynamic amplification decreases as static loading increases.

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Bridges, earth-retaining walls and buried structures make up a substantial proportion of the fixed assets of the land-based transportation infrastructure within Europe. Little work has been done on the development of documents covering the assessment of highway structures compared to the design of new structures. This paper describes an approach to assessment developed through working groups 4 and 5 of the European Cooperation in Science and Technology (Cost) Action 345, entitled procedures required for assessing highway structures. This action was supported by the European Commission and involved experts from 16 European countries. The ICE trust fund has supported a study of a road bridge in Vienna to demonstrate the applicability and potential benefits of the approach developed through Cost 345. The approach is similar to that used in the UK in that there are five levels of assessment of increasing complexity and reliability, but there are a number of differences. This paper describes the approach developed through Cost 345 with a view to opening the debate on the need for a code of practice for assessment that facilitates the use of site-specific loading. [ABSTRACT FROM AUTHOR]