This chapter describes the proof load testing of viaduct Zijlweg at a position that is critical for bending moment and at a position that is critical for shear. The viaduct Zijlweg has cracking caused by alkali-silica reaction, and the effect of material degradation on the capacity is uncertain. Therefore, the assessment of this viaduct was carried out with a proof load test. This chapter details the preparation, execution, and evaluation of viaduct Zijlweg. The outcome of the proof load test is, according to the currently used methods for proof load testing, that the viaduct fulfills the code requirements, and that strengthening or posting is not required.@en

In the Netherlands a large number of concrete bridges with post-tensioned concrete decks are in service and are constructed in the 60s and 70s of the previous century. These decks need to be investigated regarding their structural safety because of increased traffic loads in both number and intensity. An important type of prestressed bridges present in the Netherlands is constructed using prestressed T-girders and transversely post-tensioned cast in-between slab panels.

During static tests in the Stevin laboratory of the Delft University of Technology (DUT) on this type of concrete bridge decks it was found that compressive membrane action has been generated which results in a higher static bearing capacity. On the other hand it was found that when a load is applied stepwise with only three load cycles per step in about 8 h, the load capacity reduces about 16% with respect to the static capacity.

The Dutch Ministry of Infrastructure and the Environment and DUT decided that further experimental research on the influence of cyclic loading on the fatigue strength for this type of bridge deck was necessary. In total 3 static and 9 fatigue tests were performed. Based on the experimental results a relation was found between the relative fatigue strength and the logarithm of the applied number of load cycles. For 1 and 100 million load cycles a relative fatigue strength of respectively 0.54 and 0.42 was found.@en

Proof load tests of bridges can be very useful for structures with a lack of information, or for structures of which the effect of material degradation is difficult to assess. Contrary to diagnostic load testing, proof load testing is not well-defined in current standards in terms of required load and analysis of measurements. The risk related to the high loads used in proof load testing requires standardisation for these tests. The paper highlights important considerations for proof load testing that may lead to the development of guidelines in the Netherlands, by illustrating a pilot study on the viaduct Zijlweg in the Netherlands. This reinforced concrete bridge rates too low in shear. Topics of interest are the required load that the bridge has to withstand to be approved by the load test and the interpretation of the measurements during the test to avoid permanent damage to the structure. These measurements were compared to the stop criteria from existing codes for buildings, to examine if recommendations for the use with bridges can be formulated. The final result of the test on this case study is that the capacity of the viaduct is proven to be sufficient for shear and bending moment.

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Proof load testing can be a suitable method to show that a bridge can carry the required loads from the code without distress. This paper addresses the preparation, execution, and analysis of a proof load test on a four-span reinforced concrete solid slab bridge, viaduct de Beek. The bridge has one lane in each direction, but was restricted to a single lane, since an assessment showed that the capacity is not sufficient to allow both lanes. For this proof load test, the bridge was heavily equipped with sensors, so that early signs of distress can be seen. The difficulty in this test was that, for safety reasons, only the first span could be tested, but that the lowest ratings were found in the second span. A direct approval of the viaduct by proof loading was thus not possible, and an analysis was necessary after the field test. The result of this analysis is that only by allowing 6.7% of plastic redistribution in the second span, sufficient capacity can be demonstrated.@en

For existing bridges, proof-load testing can be a suitable assessment method. This paper addresses the evaluation of a posted reinforced concrete slab bridge over a highway through proof-load testing, detailing the preparation, execution, and analysis of the test. As the target proof-load and the required measurements for proof-load testing currently are not well-defined in the existing codes, this pilot case was used to develop and evaluate proposed recommendations for proof-load testing for a future guideline on proof-load testing for the Netherlands. Moreover, the pilot proof-load test is used to study the feasibility of proof-load testing for both shear and flexure@en

This is a measurement report of the test series on reinforced concrete beams without shear reinforced carried out in Delft University of Technology from April 08, 2015 till July 01, 2016. The target of the research is to investigate the transition of shear failure and bending failure. In this report, the detailed information of the experimental program is given. In addition to that, the main results of each experiment, including the description of each test, a selection of the measurement results are summarised. This report is used as an accompany to support the conclusions and the analysis of the report on the determination of the minimum shear strength before flexural failure, and other researches related to this shear – bending test series.@en

As the bridge stock in The Netherlands and Europe is ageing, various methods to analyse existing bridges are bemg studied. Proof loading of bridges is an option to study the capacity when crucial information about the structure is lacking. This information could be related to the material (for example, the effect of alkali-silica reaction on the structural capacity) as well as to the structiu-al system (for example, the effect of restraints at the supports or transverse redistribution capacity). When it is decided to proof load a bridge, the question arises which maximum load should be attained diuing the experiment to approve the capacity of tiie bridge, and which criteria, based on the measiurements during the test, would indicate that the proof loading needs to be aborted before reaching the maximum desired load (the so-called stop criteria). To defme the requked loading criteria, a review of the literature has been made, finite element models of existing viaducts have been made, and on tiiese viaducts, proof loading tests have been carried out. These bridges were heavily instrumented, with a goal of leaming as much as possible about the structural behaviour during proof loading. As a result of the analysis and experiments, recommendations are given for proof loading of bridges with respect to the required maximum load and the stop criteria. These recommendations are important, since they form the basis of a guideline for proof loading of existing concrete bridges that is under development in The Netherlands. @en