Thursday, February 23, 2017

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:

Tuesday, February 21, 2017

I am James Towers and This is How I Work

Today, I am hosting James Towers in the "How I Work" series. James holds a Bachelor’s degree in Electrical and Electronic Engineering from the Nottingham Trent University which he gained in 1996. Since then he has had a varied career in software and systems modelling and has presented both papers and tutorials at conferences and seminars as well as writing and delivering training courses on the subject. He has provided consultancy, training and mentoring to various organisations working in automotive, consumer electronics, finance, information technology, power electronics, telecommunications, rail, retail and supply chain. He is a Charted Engineer, an OMG® Certified UML professional and member of the IET, INCOSE, IIBA and chair of the INCOSE UK Model-Based Systems Engineering Working Group.

Current Job: Consultant Systems Engineer
Current Location: Brighton, UK
Current mobile device: iPhone & iPad
Current computer: MacBook Pro (Laptop) & iMac (Desktop) - Both machines run virtual machines to allow me to have a ‘virtual’ PC too

Can you briefly explain your current situation and research to us?
I’m a consultant and trainer working with companies trying to adopt Model Based Systems Engineering

I am chair of the the Model Based Systems Engineering (MBSE) Working Group at INCOSE (International Council on Systems Engineering) UK Chapter. We have a number of work-streams which research MBSE related topics. These are usually done as collaborations between multiple companies and/or academia.

What tools, apps and software are essential to your workflow?
General Office Tools (Word, Excel etc), Email, Skype. We also use Slack which is a messaging tool, Mindjet Mind Manger (for drawing mind-maps), Evernote, Things (Task Management) and specialist MBSE modelling tools such as Sparx EA, PTC Integrity Modeller, No Magic Cameo etc

What does your workspace setup look like?

Based in a home office, but often visit client sites where workshops are usually done in meeting rooms.

What is your best advice for productive academic work?
Understand your personal rhythms - not everybody works in the same way and the same time. If I’m writing a paper I find I work best late afternoon, early evening. If I’m researching existing material, or planning, mornings are best for me. Also different environments facilitate different activities. If you’re generally based in a quiet environment then it’s good to go somewhere busy with some background noise to get a different perspective (and the reverse).

How do you keep an overview of projects and tasks?

I’m a great list writer so I always have a list of tasks. For larger endeavours I’ll use a formal project plan. I also use ‘Rich Pictures’ for communication.

Besides phone and computer, do you use other technological tools in work and daily life?
Generally wedded to my phone & computer

Which skill makes you stand out as an academic?

Not an academic, but would like to do more formal research at some stage

What do you listen to when you work?
Generally shuffle my playlist.

What are you currently reading? How do you find time for reading?
Adapt: Why Success Always Starts with Failure - Tim Harford
Harold Larwood (Biography) by Duncan Hamilton

Time for reading - very difficult! Holidays and train journeys mainly

Are you more of an introvert or extrovert? How does this influence your working habits?
Mixed, but would lean towards extrovert. Which is good as I often have facilitate or run training courses.

What's your sleep routine like?
Pretty good, try for a regular sleep - wakeup cycle

What's your work routine like?
Not very routine! Lots of travel at the moment. When in the ‘office’ usually 9:00 to 17:00 when submission deadlines approach 9:00 to 19:30!

What's the best advice you ever received?

Hanlon’s Razor - ""Never attribute to malice that which is adequately explained by stupidity"

Thursday, February 16, 2017

How Original is your PhD?

Today, I am hosting Jephtah Lorch as a guest author. A former CEO, Jephtah Lorch managed technology companies, led growth, expansions and turnarounds. His work with people, scientists and engineers stressed creativity, originality and the need for constant growth and change. Mr. Lorch is a strategist, developed successful strategies for science based companies as well as major Homeland Security projects worldwide. He published the book Business is Decisions, Success is Intuition whose principles are applicable throughout our lives in personal, professional, government and organizations. Currently Mr. Lorch is the CEO of Navitas - a strategy and mentoring consultancy.

During one’s PhD research and studies the candidate is expected to make a significant original contribution to knowledge under the supervision of her or his academic supervisors. To make such contribution the candidate has to find a ‘hatch’ to originality which is driven by thought patterns – ours, our supervisors' and the environment we grow and operate in.

The opportunity to make a significant contribution differs by subject matter yet all share a common denominator: human decisions. For breakthroughs researchers need to be perceptive, open their minds to the seemingly impossible, leverage their past knowledge but not let themselves be limited by it, accept irregularities as opportunities, not threats.

Our decisions are biased by our personality, ego, loves, determination, daring, fears, education, knowledge, life experience, comfort zones and other such factors that together form our individual gut feeling. Together with intuition these, and not only, navigate some of our most strategic decisions, the unmeasurable, intangible qualitative part of our decision making that leads us to choose research fields, a research approach or methodology, the breadth of variables to be included in our research and so on. These soft decisions, like ‘it doesn’t feel right’, are influenced by our biases, our acceptance of the risk to fail, the courage to break away from glass ceilings imposed by current knowledge and ones’ determination to make that significant original contribution to knowledge.

Originality is also supported by a certain level of coincidence and chaos that continuously challenges one's thinking, exposes new patterns that do not fall in line with our original thought patterns. This happened to Wilhelm Roentgen discovering X-Rays, Henri Becquerel discovering Uranium’s natural radiation, Marie Curie discovering radioactivity, and many others. Originality is also about the curiosity and courage to pursue that disruptive idea in spite of the risk to fail, in spite of past teachings and of what our peers and seniors think of it - many of which would write off our new ideas.

The internal driving force is ourselves and one’s awareness to limiting biases, our eye for that crucial detail that challenges what we know and the determination to research it. The external driving force is normally our PhD mentor. If she or he are open minded and have egoless personalities, they will support your work without fear of having the student surpass the teacher and without limiting the scope of research to match the mentor’s boundaries.

Personal biases and soft skills make the difference before scientific or factual data does, because these steer our strategy as seen in the following historical examples.

Dr. Ignaz Semmelweis, a 19th century Hungarian physician discovered that by washing hands before surgery with a chlorine based solution patient mortality is drastically reduced. Unable to provide a scientific explanation, the medical community rejected his conclusions and continued the then-known practices. Safe in their comfort zones none of the distinguished of Austro-Hungarian professors offered to research the phenomena which was later explained by Louis Pasteur.

A more recent example is that of 2011 Nobel Prize Laureate Prof. Dan Schechtman who discovered the Quasicrystals. After first publishing his findings in 1984 he was ridiculed and rejected by the scientific community led by Linus Pauling, a two times Nobel Laureate who refused to accept he was wrong. The head of Schechtmans’ research lab told him to “go back and read the textbook”, eventually asking Schechtman to leave the lab for bringing disgrace on the team. Schechtman suffered ten very hard years until Pauling’s death and the slow recognition that his work and results are correct and revolutionary. The rejection was not scientifically based but ego-biased.

In spite of its opposition to many new findings, the academic world is sometimes willing to acknowledge novelty like in the case of Albert Einstein. The Nobel Foundation scientists, due lack of worldly proof of the Theory of Relativity, decided to award Einstein the Nobel Prize for the photoelectric effect - a much lesser discovery. Einstein’s original thinking was based on Newton’s and we can assume someone will rely on Einstein’s work bringing physics to new heights. Later on Einstein himself opposed Quantum Theory just like his peers opposed Relativity.

Research is as creative as the horizons one chooses to explore and past conventions she or he are willing to challenge. The challenge is to accept that past knowledge is not all knowledge, that originality is about breaking away from those tracks we were put on and, about awareness to human biases. Improve originality by first understanding what drives the qualitative aspects of your decision making, the intangibles driving your decisions as well as testing your courage to stand for what you believe is right.

Tuesday, February 14, 2017

I am Nels Lindahl and This is How I Work

Today, I am hosting Dr. Nels Lindahl in the "How I Work" series. Nels, an enrolled member of the Choctaw Nation of Oklahoma, is the author of Graduation with Civic Honors and founder of, which advocates development of ways to strengthen the community through volunteering networks. Nels, a Thomas and Barbara Kester Page Scholar, graduated from the University of Kansas with a degree in political science and a minor in public service and civic leadership. As an undergraduate, Nels was an Ethan Allen Scholar in public administration, on the National Deans List all four years, and participated in a study on workplace literacy with Kansas City Consensus and the Public Administration Department. Nels received a master of public administration degree from the University of Kansas department of public administration. Nels holds a doctoral degree in public policy and administration from Walden University with specializations in knowledge management and e-government. In addition to academic work, Nels is spending time working on completing a new book dealing with the intersection of technology and modernity.

Current Job: Director IT, CVS Health
Current Location: Denver, Colorado
Current mobile device: Nexus 6 (Pixel XL on the way)
Current computer: Custom built i7 processor Windows 10 system

Can you briefly explain your current situation and research to us?
I’m both a practitioner and an academic. After earning my Ph.D. from Walden University, I jumped into the workforce and have been working for the last 10 years. Working outside of education has helped support my ability to attend conferences and engage in research efforts. Those efforts involve a few different interests including e-government, e-feedback, multichannel campaign management, and data mining. Over the last few years my research efforts have primarily involved creating automated data collection systems to build out datasets for research projects.

What tools, apps and software are essential to your workflow?
The data collection systems I have built were written using Perl. I have used SPSS to work with the datasets and create visualizations.

My writing efforts tend to involve Google Docs, Microsoft Word, and EndNote. Recently I have started working with Google’s TensorFlow. I view it as a promising research tool.

What does your workspace setup look like?
My workspace is straightforward. It includes a computer, monitor, microphone, record player, and some speakers.

What is your best advice for productive academic work?
The hardest part of working in the academic space is abandoning your fear of failure and embracing the publication process. That is easier to say than to achieve. If you are passionate about writing an article, then put that passion to work and allow the creative process to take over. You must be willing to take that first step and appreciate the peer review process. Being willing to work with feedback is a part of academic life.

How do you keep an overview of projects and tasks?

I keep both to do lists and stop doing lists. The to do list typically is broken down into pieces.

Besides phone and computer, do you use other technological tools in work and daily life?
I cannot think of any tools that I utilize outside of a phone and computer.

Which skill makes you stand out as an academic?
My interest in exploring what is possible helps me stay close to the edge of the possibility frontier of technology.

What do you listen to when you work?
I listen to a Warren Zevon, Joe Satrioni, and Steve Via mixed with a ton of podcasts like Tech News Today or This Week in Google.

What are you currently reading? How do you find time for reading?

Taking a few breaks throughout the day to change directions helps me stay productive. I grab a book, journal article, or read something online for about 15 minutes. Even a 15-minute change of direction usually helps me refocus on the problem at hand. I just started reading The Phoenix Project by Kim, Behr, and Spafford (2013).

Are you more of an introvert or extrovert? How does this influence your working habits?
Without question I fall into the extrovert camp. My Myers-Briggs type is ENTJ. I generally try to push things forward and have to remember to pace myself when working with others.

What's your sleep routine like?
Based on data from my Fitbit I average 7.6 hours of sleep per night. My goal is to start the day at 5:30 AM. That requires making a point of going to bed on time instead of staying up.

What's your work routine like?
I work on coding or writing academic articles from 5:30 AM to 7:00 AM every day. During the work week, the rest of my business hours are generally spent tackling problems and engaging in coaching and development.

What's the best advice you ever received?
The best advice I ever received came in the form of a leadership philosophy. That philosophy was introduced to me by one of the most charismatic thought leaders I have known. The philosophy can be reduced to the following tenants:
1) build a strong culture,
2) let people see your commitment,
3) get to know people,
4) spend time with people,
5) empathize with others,
6) take the time to build future leaders,
7) set standards,
8) be prepared,
9) give back, and
10) foster stability while preparing for change.

Thursday, February 9, 2017

Collapse test and moment capacity of the Ruytenschildt reinforced concrete slab bridge

We recently published a paper in Structure and Infrastructure Engineering about the collapse test on the Ruytenschildt Bridge and the implications for the flexural assessment of reinforced concrete slab bridges.

The abstract of the paper is as follows:

A large number of existing reinforced concrete solid slab bridges in the Netherlands are found to be insufficient for shear upon assessment. However, research has shown additional sources of capacity in slab bridges, increasing their total capacity and possibly changing their failure mode. Previous testing was limited to half-scale slab specimens cast in the laboratory. To study the full structural behaviour of slab bridges, testing to failure of a bridge is necessary. Research on load testing is carried out in order to develop load testing guidelines. In August 2014, a bridge was tested in two spans. The bridge was load tested, and additional cycles until yielding occurred in the reinforcement were added to the experiment. Though calculations with current design provisions showed that the bridge could fail in shear, the field test showed failure in flexure before shear. The unity check for flexure was determined. The experiment shows that the methods for rating of existing reinforced concrete slab bridges are conservative.

You can access this publication directly here.

Tuesday, February 7, 2017

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:

Thursday, February 2, 2017

PhD Talk for AcademicTransfer: How to prepare for your PhD defense

This post is part of the series PhD Talk for AcademicTransfer: posts written for the Dutch academic career network AcademicTransfer, your go-to resource for all research positions in the Netherlands.

These posts are sponsored by AcademicTransfer, and tailored to those of you interested in pursuing a research position in the Netherlands.

If these posts raise your interest in working as a researcher in the Netherlands, even better - and feel free to fire away any questions you might have on this topic!

Let's talk today about the very end of the PhD journey: your defense (or viva, if you are in the UK). Depending on the university or country you are in, your PhD defense can be the very last step in a long process, on the day when you receive your diploma (as in the Netherlands), or it can be a step prior to the final submission of your dissertation (as in the USA). If you are interested in the procedures and experiences of former PhD candidates in different countries and different disciplines, be sure to check out the "defenses around the world" series on PhD Talk.

To prepare for the actual PhD defense, some argue that you don't need to do anything at all. In the end, you did your research over the past few years, and nobody knows your work as well as you do. However, going into your defense without any preparation at all is not something I recommend. If you were organized during your PhD, and starting writing your first chapters early on in your journey, you may need to revise some elements again, and reread some key publications. Moreover, your defense will depend on your committee, so preparing for your defense by keeping your committee in mind is essential. Finally, preparing for your defense will help you prepare mentally for the challenges of the day itself, and will give you some piece of mind.

As I blogged my way through my PhD, I wrote extensively about my journey to my defense, from the point where I was pottering around in the laboratory to the actual day of defense and graduation. You can read all about the steps between my draft thesis and the joyful day in "On the road to the defense" part I, part II, and my experience about the defense itself. Besides the experiences of myself and fellow PhD students, I've learned a great deal about defenses by hosting the "Defenses around the world" series on PhD Talk - a massive thank you to all guest authors who so openly have shared their experiences.

Shortly after defending my thesis, I wrote about my 10 best tips for the PhD defense, as well as how to prepare for your defense. I spent a lot of time preparing for my defense - and in hindsight perhaps not all of these activities were equally necessary. At that time, they were important for me, because spending a lot of time on preparing, and thinking about everything that could happen, helped me feel a bit more secure for the defense. If you feel like you need to prepare deeply to calm your nerves, by all accounts, do so. But if you feel confident about going into the defense, there are just a limited number of things you need to do to prepare for your defense. You can find my top picks for preparing for the defense in the following list:

1. Go to conferences
Presenting your work at academic conferences is a crucial part of your PhD journey. If you've presented your work a few times for an international audience, and answered questions, you are better prepared than when you've never had the chance to travel and present your work. Every time you present your work, you will a bit more confident about your work. Every time your present your work, you will have practiced and sharpened your presentation and presentation skills a bit more. For these reasons, use your PhD time to present at as many conferences, workshops, and industry events as possible. All this practice in the years prior to your defense will make you better prepared for the big day.

2. Know your committee and their work
The questions you can expect during your defense will depend on your committee. As you prepare for your defense, don't make the mistake of navel-gazing at your own dissertation. Instead, try to take a step back and evaluate your work through the eyes of your committee member. Check out the most recent publications of your committee members to be fully up-to-date with their work (you don't want to make the mistake of being completely oblivious when a committee member hints at the fact that he/she worked on something interesting for your research very recently). Don't assume that you read everything while preparing your dissertation - check out the latest and in press publications. If you've had a chance to meet with your committee members during your PhD and while preparing for the defense, revise your meeting notes, and identify their main points of criticism on your work. While some committee members will tell you their exam questions in advance, other members won't give you an idea, and will leave you guessing. Try to come up with at least five possible questions per committee member, and prepare additional material to answer these questions as needed.

3. Revise the crucial papers
Brush up on your knowledge of the literature. Besides checking the most recent work of your committee members, make sure that you do a brief search on recent publications in your field, so that your literature review and your knowledge of the literature are fully up-to-date. Don't stop following the literature on the day when you finish your literature review chapter! Besides working on your general knowledge of the literature, identify the papers that were most important for your work. Prior to your defense, make sure you read these papers again to refresh your memory, and to address possible questions about the foundations of your work.

4. Prepare for broader questions
When preparing for your defense, don't expect any open doors. Instead, you should prepare for questions that are either at the periphery of your work, and much closer to the work of your committee members, or for questions that test the assumptions and basics of your work. Make sure you have a solid foundation to answer such questions. Besides these questions that sit right outside of what was the main focus of your work, there are also the questions that focus on the broader scope of your work, other fields of application, and future work. Such more general questions can be asked at any PhD defense, and you can find a list of possible questions here, here, and, here. Make sure you practice preparing answers to these questions, and bring additional material for the defense where needed.

5. Know the room and the tools you can use
Get your logistics for the day of your defense all sorted out long in advance. You don't want to be running around campus, borrowing a laptop last-minute, or arranging coffee for your committee members. Ask for advice from a post-doc who recently defended to see if you thought everything through. Make sure you understand all the procedures, and when in doubt, ask and double-check with the office responsible for the defense. Know where you will present, and which tools are available in the room. Will you be using a microphone? Will you be able to project visual material and use audio in the room? Are there other tools available? In Delft, the rooms standard have a digital overhead projector, which you can use to show parts of your dissertation, sketches, and other material. Depending on the tools you have available, make sure you bring the right material to your defense.

6. Be your best self
Don't get too stressed about the defense itself. If you get stressed, you'll have a harder time thinking clearly and replying the questions in a way that is satisfactory for the committee. I started my defense really nervous, and I can barely remember how replying the first questions went. Once I got calmer, everything went much better. Besides your stress levels on the day itself, make sure that you are rested prior to the defense. Get enough sleep in the weeks before the defense, and eat healthy food. Consider yourself as an athlete preparing for a big effort: make sure you are in your best condition to give it your all on the day of the defense.

7. Plan your party
Your defense is a day when your friends and family gather to celebrate your success. Don't forget how important and valuable this day is for all of you in your stress for preparing for the actual defense. Unless for weddings and perhaps special birthdays, there are not that many occasions where you can have that many of your loved ones together, to celebrate you and your success. Your family may even be traveling internationally to attend this special event. A special event it is, so make sure you make it a special day for everyone attending. Arrange a reception and a nice dinner, for example, or any other form of celebration as you see it fit.