Adaption of Load Models for Assessment of Existing Bridges

Beschreibung

Bridge infrastructure is essential for keeping the flow of goods around Europe going. The weight of goods being transported across them is substantial and the operating freight vehicles produce considerable loading of bridge structures.
Existing engineering structures in today’s road network were designed according to the national rules and standards at the time of planning/construction. The age of these structures shows that a large proportion of them is 40 years or for rail bridges even older. For road bridges the current load models in EN 1991-2 are based on traffic surveys in 1986. The bridges are designed to withstand traffic loading events that have a statistical return period of 1000 years, or a 5% probability to be exceeded within 50 years. In order to evaluate the reliability of a specific bridge, the maximum traffic load that is expected to occur during bridge operation needs to be known. Therefore, the standard load models in the codes are designed for very unfavourable load situations - traffic jams, heavy traffic and special transports. Ongoing developments in vehicle technologies (automated traffic, truck platooning or E-Trucks) allow additional more accurate traffic surveys and evaluation of the load models. Traffic behaviour and load distribution changes and provide different loading types.
Another challenging task is aging and deterioration due to fatigue especially for steel railway bridges. The structures are essential network components which cannot be replaced without considerable financial investments and interruption to railway operation. More and more railway steel bridges are near the end of their service lifetime. Infrastructure owners must guarantee that the bridges are safe to operate and strive to maintain and renew these bridges in the most economic, socially, and environmentally sustainable way without compromising the reliability of the structures. The load models given in the design codes, are often far too conservative. Historical loading is not always known, so real assessment and calibration of route or object specific loading can help to improve the assessment and extend the prognosis of remaining lifetime prediction.
This talk presents how new sensor technologies and databases in road and rail infrastructure can be used to improve the assessment of existing bridges. Sensor data from traffic flows measurement, weight in motion stations (WIM), video data, historical train operating data are still unused when it comes to engineering structures. The optimised use of these data would allow today’s traffic scenarios to be determined more reliably, and thus provide more realistic parameters for site specific load models regarding assumptions of the likelihood of traffic jams, special heavy vehicles, lane changes or object specific (historical)-load collective for fatigue assessment. The potential by combining scientific probabilistic simulations and site-specific sensor information of loads and structural health monitoring will be presented on different examples and case studies. It will be demonstrated how existing load models can be calibrated for ultimate limit state and fatigue assessment. An other aspect is evaluation the effects on the bridge stock for new loading types like truck platooning or changed axel loads due E- trucks.

Zeitraum	19 Okt. 2023
Ereignistitel	2nd Global Meet on Civil, Structural and Environmental Engineering
Veranstaltungstyp	Konferenz
Ort	Barcelona, SpanienAuf Karte anzeigen