Testing Bridges to Failure - Experiences

Abstract

Four bridges of different types have been tested to failure and the results have been compared to the load-carrying capacity calculated using standard code models and advanced numerical methods. The results may help to make accurate assessments of similar existing bridges. Here it is necessary to know the real behaviour, weak points, and to be able to model the load-carrying capacity in a correct way. The four bridges were: (1) a one span steel truss railway bridge; (2) a two span strengthened concrete trough railway bridge; (3) a one span concrete trough bridge tested in fatigue; and (4) a five span prestressed concrete road bridge. The unique results in the paper are the experiences of the real failure types, the robustness/weakness of the bridges, and the accuracy of different codes and models.

GNSS (GPS) Monitoring of Dynamic Deflections of Bridges: Structural Constraints and Metrological Limitations

“…The only exception is a reinforced concrete bridge in Kiruna, Sweden, which was subject to controlled loading till failure. In this case, total failure occurred when the vertical deflection reached approximately 300 mm [21]. These results indicate that deflections of structurally healthy, stiff bridges can hardly exceed 1 cm in amplitude, and deflections of the order of tens of centimeters are associated with structural damage.…”

Cracking and Fatigue of Heavy Loaded Prestressed Concrete Bridge in Sweden

“…The bridge, as other bridges that have been tested, seems to have a considerably higher capacity than the original design calculations indicated. Tests to failure for bridges have shown differences, e.g., in material properties, load distribution support conditions and code models, which have resulted in considerable extra "hidden" capacities as presented in [6] - [15]. Society may learn and save money from the experiences from "full-scale" failure tests.…”

“…The shear capacity is hard to model correctly with code models, as has been shown in several fullscale tests to failure, see e. g. Bagge et al [6] - [9], Nilimaa et al [10], [11], Bien et al [12], Elfgren et al [13], [14] and Häggström et al [15]. As mentionend, according to the original design there were only very small principle stresses and they could be carried by the concrete.…”

“…A more detailed fatigue analysis can also be made with the Rain-Flow method and with Palmgren-Miner hypothesis [21], [22] according to the same method as has been used by Häggström [15], [23,24] in the analysis of two twin railway metal truss bridges.…”

Assessment of Prestressed Concrete Bridges - Challenges

“…Bagge et al [8] and Elfgren et al [25], [26]. It has also been successfully used in European projects as Sustainable Bridges (2007) [27]- [29] and MAINLINE (2014), Häggström et al [30].…”