Presentation about Load Testing of Structures

The ACI USFQ Student Chapter organized a session with presentations last October. I gave a general introduction to the session, as well as an overview of load testing of structures. You can find my slides here:

Load testing of structures from Eva Lantsoght

10 Planning Concepts I Wish I'd known Before my PhD

On March 14th, I gave a presentation for the opening of the academic year as part of the XV week of Postgraduate Studies for the School of Engineering at Universidade de Sao Paolo in Sao Carlos. The topic of this presentation was time management for graduate students.

I couldn't make the trip to Brazil (the Toddler Empress did not approve), but I gave the presentation by videoconference. I'm grateful to USP - Sao Carlos for hosting me.

Here are the slides of my presentation:

10 Planning Concepts I wish I'd known Before my PhD from Eva Lantsoght

The recording of the presentation is on YouTube:

Papers and presentations from IALCCE 2018

Last fall, I attended IALCCE 2018 where together with my colleagues from TU Delft, I organized a Mini Symposium on Load Testing of New and Existing Structures.

For this MS, I submitted 4 papers as coauthor - 3 of these papers are the results of projects with B.Sc. thesis students from USFQ funded by my 2016 Chancellor Grant. During the MS, I presented my work on stop criteria and I also presented about diagnostic load testing of steel bridges on behalf of ADSTREN.

The abstracts of the papers are:
Proposed stop criteria for proof load testing of concrete bridges and verification
Eva Lantsoght, Cor van der Veen, Dick Hordijk
In a proof load test, a load representative of the factored live load is applied to the bridge. Since the applied load is large, stop criteria are important. Stop criteria for shear and flexure are proposed based on existing codes and guidelines, laboratory experiments, and theoretical considerations. This proposal is verified with the results from pilot proof load tests. The result of this comparison is that the stop criteria are never exceeded, or that they are exceeded only in the last load step. The proposed stop criteria are thus not overly conservative for application to field testing. However, information about the available margin of safety is not always available, especially for shear failures, and will need further experimental validation.

Nonlinear finite element analysis of beam experiments for stop criteria
Jose Eduardo Paredes, Eva Lantsoght
Proof load testing is used to assess the structural capacity of existing bridges. Stop criteria, based on measurements taken during proof load tests, determine if a test should be stopped before reaching the target proof load in order to maintain structural integrity. A nonlinear finite element model is proposed to investigate stop criteria. A reinforced concrete beam with plain reinforcement is modeled. The goal is to develop a reliable finite element model with adequate material constitutive models to analyze available stop criteria from existing codes. The beam experiment is verified in terms of strains. Stop criteria from ACI 437.2M-13 and the German guideline are analyzed for the beam model. The presented analysis shows that nonlinear finite element models can be used for the evaluation of stop criteria for proof load testing to limit the required number of laboratory tests.

Development of a stop criterion for load tests based on the critical shear displacement theory
Kevin Benitez, Eva Lantsoght, Yuguang Yang
The capacity of existing bridges is an important aspect regarding the safety of the traveling public.
Proof load testing can be a useful option to evaluate if an existing bridge satisfies the requirements from the code. The stop criteria provided by the Guidelines are generally suitable for flexure only. Therefore, in this paper, shear is considered. When developing a stop criterion for shear for proof load tests on existing bridges, many different approaches could be taken. Here, a stop criterion is developed based on the Critical Shear Displacement Theory. The development of the stop criterion is based on the analysis of the contribution of each of the mechanisms of shear transfer. The criterion is verified with experiments on beams in the laboratory. The consequence of this development is that now a stop criterion for shear with a theoretical basis is provided.

Verification of flexural stop criteria for proof load tests on concrete bridges based on beam experiments
Andres Rodriguez, Eva Lantsoght
When performing proof load tests, irreversible damage may occur. Guidelines for performing the test have been developed, which establish stop criteria to terminate the test before this happens. The stop criteria prescribed in the currently available codes are mainly designed for buildings, but load tests are also performed on bridges. This investigation compares the results from beams tested in the laboratory with stop criteria and analyzes their applicability on reinforced concrete bridges. The stop criteria from ACI 437.2M-13, the German guideline of the DAfStB, and a proposal developed by Werner Vos from TU Delft were evaluated. It was found that the DAfStB concrete strain stop criterion provided the most consistent results. The ACI stop criteria should only be applied if the ACI loading protocol is being followed. The deflection proposal by Vos, seems to be a reliable option, but further investigation needs to be done before it can be applied.

The slides of the presentations are:

Proposed stop criteria for proof load testing of concrete bridges and verification from Eva Lantsoght

Diagnostic load testing of bridges - case studies from Eva Lantsoght

Proof load testing of viaduct De Beek

I recently gave a presentation about a case study of a proof load test at the IABSE event organized by the national groups of Belgium and the Netherlands.

You can find the slides of the presentation here:

Proof load testing of viaduct De Beek from Eva Lantsoght

Stop criteria for proof load tests verified with field and laboratory testing of the Ruytenschildt Bridge

My colleagues and myself recently published a paper titled "Stop criteria for proof load tests verified with field and laboratory testing of the Ruytenschildt Bridge" and presented this at the IABSE Conference 2018 "Engineering the Past, to Meet the Needs of the Future", held June 25-27 2018, in Copenhagen, Denmark.

The abstract of the paper is as follows:
As the existing bridge stock is aging, improved assessment methods such as proof load testing become increasingly important. Proof load testing involves large loads, and as such the risk for the structure and personnel can be significant. To capture the structural response, extensive measurements are applied to proof load tests. Stop criteria, based on the measured quantities, are used to identify when further loading in a proof load test is not permitted. For proof load testing of buildings, stop criteria are available in existing codes. For bridges, recently stop criteria based on laboratory tests on beams reinforced with plain bars have been proposed. Subsequently, improved stop criteria were developed based on theoretical considerations for bending moment and shear. The stop criteria from the codes and the proposed stop criteria are compared to the results from field testing to collapse on the Ruytenschildt Bridge, and to the results from laboratory tests on beams sawn from the Ruytenschildt Bridge. This comparison shows that only a small change to the stop criteria derived from laboratory testing is necessary. The experimental evidence strengthens the recommendation for using the proposed stop criteria in proof load tests on bridges for bending moment, whereas further testing to confirm the stop criteria for shear is necessary.


You can find the slides of the presentation here:

Stop criteria for proof load tests verified with field and laboratory testing of the Ruytenschildt Bridge from Eva Lantsoght

Sound applications in Engineering

Last semester, I presented during the colloquium of the School of Engineering and Sciences of USFQ. The topic of my talk was applications of sound in engineering.

Even though there are multiple uses of sound in engineering, most engineering schools do not offer acoustic engineering as a career. In this presentation, I show the vast variety of applications of sound. We start with the architectural acoustics, discussing how different buildings with different uses require a different treatment of sound. I showed a fascinating TEDx talk about how to design rooms that have unique acoustic features. Then, I made the jump to the applications of sound in civil engineering, with as an example of how better asphalt mixes can be used for noise reduction. Finally, I brought the topic to my field, bridge engineering. Here, we see different non-destructive testing methods that use sound waves (or other types of waves) to look inside a material of a bridge. We talked about acoustic emission measurements, a way of listening to what happens inside a bridge when it is loaded. Finally, I discussed how we use these type of measurements during load testing of bridges, and showed the example of the collapse test of the Ruytenschildt Bridge.

You can find the slides of this presentation here:

Sound in engineering from Eva Lantsoght

Two presentations at IABSE 2017

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 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.

You can find the slides of the presentation here:

Proof load testing of the viaduct De Beek from Eva Lantsoght

The second paper is titled "Recommendations for proof load testing of reinforced concrete slab bridges" with the following abstract:

Proof loading of existing bridges is an option to study the capacity when crucial information about the structure is lacking. To define the loading criteria for proof load testing, a review of the literature has been made, finite element models of existing viaducts have been made, and on these viaducts, proof loading tests have been carried out. These bridges were heavily instrumented, to learn as much as possible about the structural behaviour during proof loading. Additional laboratory experiments have been used to develop controlled loading protocols, and to identify which stop criteria can be used for which case. 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 have resulted in a guideline for proof loading of existing reinforced concrete slab bridges for The Netherlands.

This paper was presented in a poster session, with a short pitch. The pitch is as follows:

Recommendations for proof load testing of reinforced concrete slab bridges - presentation from Eva Lantsoght

The poster is:

Recommendations for proof load testing of reinforced concrete slab bridges - poster from Eva Lantsoght

Assessment of slab bridges through proof loading in the Netherlands

I recently gave a presentation at the ACI Fall Convention in Anaheim, CA about our research on proof load testing of slab bridges. If all goes well, the paper will be published in an ACI SP. Below, you can find the slides of this presentation:

Assessment of slab bridges through proof loading in the Netherlands from Eva Lantsoght

Beam experiments to investigate loading protocol and stop criteria for load testing

I recently presented a poster about our research on load testing in Delft at the ACI Spring Convention in Detroit, MI.

Poster presentations are not something I'm quite used to. I've written about my experience presenting a poster for the first time (in 2012), and since presenting that poster, I've only given lectern sessions. Besides that, I've made two posters for the research school of building and construction of the Netherlands, for their book of research projects, way back in 2009 and 2010.

The poster sessions was well attended, and I enjoyed the direction interaction with the audience. As such, I'd vote in favor of adding more poster presentations to the conferences in my field (as long as we can consider them as equal to lectern sessions, instead of considering them as a little "less" valuable).

You can find the poster here (you can scroll through it):

Beam experiments to investigate loading protocol and stop criteria for load testing from Eva Lantsoght

Reliability index after proof load testing: viaduct De Beek

My colleagues and I recently published a paper in the proceedings of the ESREL (European Safety and Reliability Conference), held in June in Portorož, Slovenia. My colleague presented the paper, as I was too far advanced in pregnancy to be allowed on a flight.

The abstract of the paper is:

Proof load tests can be used for a field assessment of the bridge under study. This paper addresses the determination of the reliability index of an existing bridge by means of proof loading through the case study viaduct De Beek. The information of this bridge is used to determine the updated reliability index after proof load testing. A sensitivity study is carried out to identify the effect of the assumptions with regard to the coefficient of variation on the resistance and load effects. In the current practice of proof load testing with vehicles, it can typically only be demonstrated that a certain vehicle type can cross the bridge safely. The results in this paper provide a new insight on the updating of the reliability index after proof load testing. Consensus on the coefficients of variation that need to be used on the resistance and load effects, is still missing.

You can find the slides here:

Reliability index after proof load testing: viaduct De Beek from Eva Lantsoght

Determination of loading protocol and stop criteria for proof loading with beam tests

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 standard loading protocol for the proof loading of reinforced concrete slab bridges. Recommendations for the use of the stop criteria are also formulated. These insights are used to develop a new guideline for the proof loading of reinforced concrete slab bridges in the Netherlands.

Here you can find the slides of the presentation:

Determination of loading protocol and stop criteria for proof loading with beam tests from Eva Lantsoght

Extended Strip Model for slabs subjected to a combination of loads

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 line load. The result of this comparison is that the proposed method is suitable to find a safe estimate of the maximum concentrated load on the slab. The implication of this development is that an improved tool is available to estimate the maximum load of a truck that can be placed on a reinforced concrete bridge, thus improving the current assessment.

Here you can find the slides of the presentation:

Extended Strip Model for slabs subjected to a combination of loads from Eva Lantsoght

Proof load testing in the Netherlands - overview of current research

At the ACI Spring Convention in Detroit, MI, I gave a presentation in the committee meeting of ACI 437. In this presentation, I gave a quick overview of the research we've been doing in the Netherlands related to load testing.

You can find the slides of this presentation below:

Proof load testing in the Netherlands - overview of current research from Eva Lantsoght

Q&A: Participating in roundtable discussions

I recently received the following email from a reader (edited for anonymity):

Hi,
I am invited to participate in a roundtable discussion next month, and I was wondering if you have any tips for participants. I am a PhD candidate and the roundtable is focused on Some Topic which was the focus of my last degree, an MPhil. I am excited to participate, but tend to be a quieter, more reserved personality, and I want to do well on this, my first, roundtable.

I took quite some time before replying this message. Since I tend to be more quiet and reserved myself, I am not the person who is the most active participant in discussions during committee meetings. However, I think I have found what works for me, with my personality, and still being of service during such presentations:

1. Volunteer for keeping minutes

If you can, you can offer the chair of the discussion to keep the minutes for the meeting and develop the report afterwards. Your action will be valued, even though you may not have spoken much during the meeting. If you are taking notes, you can also at some point ask another researcher to expand on a point that is interesting, for your personal interest but also to complete the report of the meeting.

2. Think ahead of a few topics to discuss

Before the discussion, you can think ahead about different subtopics that can come up during the discussion. Which point would you want to get across on each of these topics? What evidence do you have to support your claims? You may want to have a short preparation with the references you may want to mention on your laptop to refer to when you speak.

3. Think ahead of questions you want to share with others

To move the discussion forward when it gets stalled, you can prepare some questions that you may want to bring up for other participants in the discussion. You may for example prepare some questions in the following style: "Author X found result X, which contradicts findings from Y. I've been thinking about this discrepancy for a while now, and I have the impression that factors A,B, and C can explain this. I'd like to elaborate a bit more on this topic in this group. What is your opinion on this topic?" By formulating a question in this way you show the thinking and the work you've done, but you also open room for discussion and participation with others instead of just voicing your opinion.

4. Summarize the results you want to show

This element is closely related to nr. 2. If you did the work on this topic a while ago, you may want to make a short summary of your most important results for yourself, and have it on your laptop to look at if you need to refresh your memory. You may want to revise again the most important publications on the topic. If you make a claim, you can refer to these publications. If the paper does not seem to ring a bell for the other members, you can propose to pass it around on a stick or project the paper to show some of the main results and discuss this. Similarly, you can have a few graphs or tables with your main results that you can show by projecting this information during the meeting.

5. Don't speak too quietly

If you tend to be a more quiet person, you may also have the tendency to speak a little more quiet. If your voice is naturally quiet, see if you can use a microphone, or try to speak up, so that your opinion and contribution does not get drowned by the others. If you feel a bit nervous, try to speak slowly and breathe with your diaphragm to calm yourself.

Proof load testing of reinforced concrete slab bridges in the Netherlands

I recently presented a paper at the annual meeting of TRB, the Transportation Research Board. The abstract of the paper is as follows:

The bridges built during the development of the Dutch road network after the Second World War are reaching their originally devised service life. A large subset of the Dutch bridge stock consists of reinforced concrete slab bridges. This bridge type often rates insufficient according to the recently introduced Eurocodes. Therefore, more suitable methods are developed to assess reinforced concrete slab bridges to help transportation officials make informed decisions about the safety and remaining life of the existing bridges.
If information about a bridge is lacking, if the reduction in structural capacity caused by material degradation is unknown, or if an assessment shows insufficient capacity but additional capacity can be expected, a bridge might be suitable for a field test. A proof load test demonstrates that a given bridge can carry a certain load level. In the Netherlands, a number of existing reinforced concrete slab bridges have been proof loaded, and one bridge has been tested to collapse. Bridges with and without material damage were tested. These bridges were heavily instrumented, in order to closely monitor the behavior of the bridge. Critical positions for bending moment and shear were studied.
Based on the proof load tests that were carried out over the past years, a set of recommendations for the systematic preparation, execution, and analysis of proof load test results is compiled. These recommendations will ultimately form the basis of the guideline for proof load testing for the Netherlands, which is currently under development.

You can find the slides here:

Proof load testing of Reinforced Concrete Slab Bridges in the Netherlands from Eva Lantsoght

The adventures of a concrete researcher - or how I ended up breaking bridges for a living

I recently gave a presentation to the ACI Student Chapter of Universidad San Francisco de Quito. They asked me to tell something accessible about doing experiments, so I decided to chronicle my journey to the work that I am currently carrying out.

Here are the slides of the presentation:

The adventures of a concrete researcher - or how I ended up breaking bridges for a living from Eva Lantsoght

Papers at SEMC 2016

This year, I was author and co-author of three papers at SEMC 2016, the conference on Structural Engineering, Mechanics and Computation in Cape Town, South Africa. While I did not have the chance to travel, my students Mr. Valdivieso and Mr. Mejia traveled to present their thesis work, and Dr. van der Veen traveled to present our co-authored paper.

The abstract of mr. Mejia's paper is:

Throughout history invasive methods for analyzing deflections and deformations have been used in concrete structures at the laboratory, but the advancement of technology has allowed the development of new non-invasive alternative methods such as digital image correlation (DIC). With this technique, it is possible to obtain information about the deflections, strains and strain fields in a structure. The current study consists of performing a flexural test on plain concrete beams and concrete arches reinforced with FRP rein-forcement. All tests were recorded with a cheap, small camera, then transferred into a series of images in or-der to apply the digital image correlation technique. The analysis with DIC results in the displacements, strains and strain fields of the surface under analysis. Finally, the percentage of error between the displace-ment derived from the DIC technique and the displacement measured by Linear Variable Differential Trans-formers (LVDTs) is calculated. In conclusion, the study shows that it was not possible to reach accuracy on the values of deflections and strains by the applied method and that a higher-speed camera is necessary to capture the moment of failure.

The abstract of mr. Valdivieso's paper is:

A large number of existing bridges in Europe and North-America are reaching the end of their devised service life. Therefore, it is necessary to improve the methods of assessment for existing bridges. One method, suitable for existing reinforced concrete slab bridges, is the Modified Bond Model. This method, however, currently only takes the effect of torsion for loads close to the edge into account in a simplified manner. In this study, finite element models are created of a slabs with two supports, three concentrated (pre-stressing) loads and a distributed load, representing a truck wheel print. The load is varied along the longitu-dinal and transverse directions of the slab to find the bending moments (mx and my) and torsional moments (mxy). The results is an expression for the effect of torsion in slabs, which can be used with the Modified Bond Model for assessment and design of slab bridges.

The abstract of the paper of which I am first author is:

For the assessment of existing structures and the design of new structures, it is important to have a good understanding of the flow of forces, here applied to reinforced concrete solid slabs. Two analyti-cal methods are used: finite element models with 3D solid elements and a plasticity-based model that is suita-ble for hand calculations, the Modified Bond Model. The slabs that are modeled are half-scale models of rein-forced concrete solid slab bridges. As the Eurocode live load model prescribes more heavily loaded trucks in the first lane, the load model is asymmetric. For the finite element models, limited use is made of the redistri-bution capacity of the slab. For the Modified Bond Model, the influence of torsion and the edge effect need to be taken into account. The results of these studies improve the current state-of-the-art for analysis and design of reinforced concrete slabs.

Here are the slides of my paper:

Modeling of symmetrically and asymmetrically loaded reinforced concrete slabs from Eva Lantsoght

Defining loading criteria for proof loading of existing reinforced concrete bridges

Recently, at the fib symposium 2016 in Cape Town, I presented a paper that I co-authored with a junior colleague, who wrote his first paper. Here is the abstract of the paper:

As the bridge stock in The Netherlands and Europe is ageing, various methods to analyse existing bridges are being 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 structural 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 during the experiment to approve the capacity of the bridge, and which criteria, based on the measurements 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 define the required loading criteria, a review of the literature has been made, finite element models of existing viaducts have been made, and on these viaducts, proof loading tests have been carried out. These bridges were heavily instrumented, with a goal of learning 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.

Please find below my slides of the presentation:

Defining loading criteria for proof loading from Eva Lantsoght

Shear Capacity of the Ruytenschildt Bridge

I recently presented a paper at the 2016 fib symposium in Cape Town on the shear capacity of the Ruytenschildt Bridge. The abstract of the paper is as follows:

In August 2014, the Ruytenschildt Bridge, a reinforced concrete solid slab bridge (reinforced with plain bars) in the Friesland province in the Netherlands was tested until failure. One of the goals of proof loading and testing this bridge to failure, was to study the failure mode of existing slab bridges. The combination of smaller shear capacities as prescribed by the Eurocode in combination with the heavier live load models, has raised concerns with regard to a number of existing slab bridges in the Netherlands. As the shear capacity of existing bridges is under study, the results of testing an actual slab bridge until failure are used to compare to the results of testing half-scale slab specimens in the laboratory, and the conclusions resulting from those experiments. In this paper, the results of the predictions based on the first order of approximation rating procedure from the Netherlands for shear, the Quick Scan method, as well as based on predictions of the failure mode and the average predicted capacity are compared to the experimental results. The predictions show a possibility of shear failure in the second span of the bridge. The experiment showed that both spans of the bridge failed in flexure. The observed failure mode is important, as some of the results indicate that the solid slab bridges, currently under discussion with regard to their shear capacity, fail in flexure in reality. Flexural failure is considered a ductile failure compared to the brittle failure mode in case of a shear failure.


Please find below the slides of my presentation:

Shear capacity of the ruytenschildt bridge from Eva Lantsoght

Load testing of reinforced concrete bridges in the Netherlands

I recently gave a guest lecture at my alma mater, Vrije Universiteit Brussel. You can also find some photographs of this even on the Facebook page of the group Mechanics of Materials and Constructions.

The abstract for the presentation was as follows:

As the bridge stock in The Netherlands and Europe is ageing, various methods to analyze existing bridges are being studied. Load testing 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 ASR on the capacity) as well as to the structural system (for example, the effect of restraints at the supports or transverse redistribution capacity).
When it is decided to load test a bridge, the question arises which maximum load should be attained during the experiment to approve the capacity of the bridge, and which criteria, based on the measurements during the test, would indicate that the test needs to be aborted before reaching the maximum desired load (the “stop criteria”).
A number of reinforced concrete slab bridges have been load tested over the course of the past few years. These load tests were pilot cases, in which the bridges were heavily equipped with sensors, to study the bridges’ behavior at critical positions for bending moment and shear. The test results were then extensively analyzed, and compared to the stop criteria available in the currently used codes and guidelines.
As a result of the analysis and experiments, recommendations are given for proof loading of bridges. These recommendations are important, since they will form the basis of a guideline for proof loading of existing concrete bridges that is under development in The Netherlands.

You can find the slides of the presentation here:

Load testing of reinforced concrete bridges in the Netherlands from Eva Lantsoght