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At IABSE 2017 , my colleague presented two papers of our research. I didn't travel to IABSE, because the conference fell right in the middle of my maternity leave. The first paper is titled "Proof load testing of the viaduct De Beek" and the abstract is as follows: 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 di...

My colleagues and myself recently published a paper in the Journal of Bridge Engineering, titled "Pilot Proof-Load Test on Viaduct De Beek: Case Study". The paper reports on the proof load test on viaduct De Beek which our research group carried out in November 2015. I couldn't join my colleagues in the field at that time, but in the summer of 2016, I helped finalizing the analysis report of the test. The abstract is as follows: 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 Nether...

My colleagues and I recently published a paper titled "Plastic model for asymmetrically loaded reinforced concrete slabs" in a Special Publication of the ACI, ACI-SP 321 "Recent Developments in Two-Way Slabs: Design, Analysis, Construction, and Evaluation". This SP is the result of a session held at the ACI Fall Convention in 2015. You can purchase the SP through the ACI website. The abstract of our paper is as follows: Most methods for the design and analysis of reinforced concrete slabs for punching are based on experiments on slab-column connections, reflecting the situation in building slabs. Slab-column connections with unbalanced moments have also been studied in the past. Experiments indicate that the accuracy of models for asymmetrically loaded slabs is lower than for symmetrically loaded slabs. In this paper, the difference in accuracy between test predictions for symmetrically and asymmetrically loaded slabs is tackled. A plastic model, the Extended Strip ...

My co-authors and myself recently published a paper in Structure and Infrastructure Engineering about the load test on viaduct Zijlweg. The paper is titled "Towards standardisation of proof load testing: pilot test on viaduct Zijlweg". You can access the paper through this link . The abstract is as follows: 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 t...

At the fib symposium 2017, I presented a paper titled "Determination of loading protocol and stop criteria for proof loading with beam tests". The abstract of the paper is as follows: Proof loading of existing bridges is an interesting option when insufficient information about a bridge is available. To safely carry out a proof loading test, high loads are placed on the bridge. To avoid permanent damage to the structure, a controlled loading protocol needs to be described, and the measurements need to be closely monitored to identify the onset of distress. The criteria from existing codes and guidelines to evaluate the measurements, called stop criteria, are not universally applicable. To develop recommendations for proof loading of reinforced concrete solid slab bridges, beam experiments were analysed. The beams were heavily instrumented to evaluate the existing stop criteria, and possibly develop new stop criteria. The result of these experiments is the development of a sta...

I recently presented a paper titled "Extended Strip Model for slabs subjected to a combination of loads " at the fib symposium in Maastricht. The abstract of the paper is: Reinforced concrete slab bridges are assessed for a combination of loads that include self-weight, superimposed loads, and distributed and concentrated live loads. The shear capacity of reinforced concrete slabs subjected to a combination of loads is thus an important topic for the assessment of existing bridges. Currently, a plastic model exists for the assessment of reinforced concrete solid slabs subjected to a concentrated load: the Extended Strip Model, based on the Strip Model for concentric punching shear. To apply this model to slabs subjected to a combination of loads, the model needs to be adapted based on theoretical principles. The results are then compared with the results from experiments on half-scale slab bridges subjected to a combination of a concentrated load close to the support and a li...

My colleagues and I recently published a paper in Engineering Structures, titled "Development of recommendations for proof load testing of reinforced concrete slab bridges". You can download the paper for free for the next 50 days through this link. This paper is the last journal paper in a series of papers based on the research I carried out with regard to proof load testing. I have a few more conference papers planned on smaller analyses that I did as part of the research, but my data are depleted by now. On to new research and/or more testing to deepen this topic (wherever the funding takes us)! The abstract of the paper is as follows: As the bridge stock in the Netherlands and Europe is ageing, various methods to analyze existing bridges are being studied. Proof load testing of bridges is an option to experimentally demonstrate that a given bridge can carry the prescribed live loads. Based on extensive research on proof load testing of reinforced concrete slab bridges car...

My coauthors and myself recently published a review paper on load testing, titled "State-of-the-art on load testing of concrete bridges" in Engineering Structures. You can download the article for free until September 13th 2017 by accessing this link. The abstract of the paper is as follows: Load testing of bridges is a practice that is as old as their construction. In the past, load testing gave the traveling public a feeling that a newly opened bridge is safe. Nowadays, the bridge stock in many countries is aging, and load testing is used for the assessment of existing bridges. This paper aims at giving an overview of the current state-of-the-art with regard to load testing of concrete bridges. The work is based on an extensive literature review, dealing with diagnostic and proof load testing, and looking at the current areas of research. Additional available information about load testing of steel, timber, and masonry bridges, buildings, and collapse testing is briefly cit...

We recently published a paper titled "Modeling Concrete Material Structure: a Two-Phase Meso Finite Element Model". The work reported in this paper was a collaboration with the department of mechanical engineering of Universidad San Francisco de Quito. My colleague Dr. Bonifaz developed a coupling between Dream3D and Abaqus for modeling metal materials. In our collaboration, we looked at the possibility to apply these concepts to concrete. You can find the full paper here . The abstract reads as follows: Concrete is a compound material where aggregates are randomly placed within the cement paste. To describe the behavior of concrete structures at the ultimate, it is necessary to use nonlinear finite element models, which for shear and torsion problems do not always give satisfactory results. The current study aims at improving the modeling of concrete at the meso-level, which eventually can result in an improved assessment of existing structures. Concrete as a heterogeneous m...