Shear capacity of steel fibre reinforced concrete beams

My student Belkis Filian recently traveled to Poland to present her research at the fib symposium in Krakow.
The title of her work was: "Shear capacity of steel fibre reinforced concrete beams". We also worked with my TU Delft colleague Yuguang Yang for this paper, and looked at a simple way to incorporate the effect of steel fibers in the critical shear displacement theory (disclaimer: the crack kinematics are so complex that "simple" methods unfortunately are only very coarse approximations)

Here's the abstract:
The Critical Shear Displacement Theory (CSDT) was developed to determine the shear capacity of reinforced concrete beams based on the different shear-carrying mechanisms (concrete in the compression zone, aggregate interlock, and dowel action). This research aims at extending the CSDT to Steel Fibre Reinforced Concrete (SFRC) by adding the contribution of steel fibres. The model extension was developed based on formulations for the contribution of steel fibres to the shear capacity from the literature. With this extension to the CSDT, the shear strength of steel fibre reinforced concrete beams without stirrups could be estimated. An extensive database is developed from the literature in order to evaluate, compare, and analyse the shear capacity of SFRC beams. The analysis indicates that two models are capable of predicting the shear strength of SFRC beams with reasonable accuracy. The mean, standard deviation, and coefficient of variation are 0.9, 0.28, 0.31 and 1.1, 0.33 and 0.30 respectively. The main geometric variables of the steel fibres that influenced the shear strength are the length, diameter, and fibre type (hooked, crimped, and straight). From the comparison between the results in the database and the proposed extensions to the CSDT it is found that the critical shear displacement of Δcr = 0.025 mm, gives reasonable results for SFRC. As such, this proposed method can be used to estimate the shear strength of SDRC based on a mechanical model.

Feel free to write me if you want a copy of the paper!

Are we sleeping enough?

I recently read "Why we sleep" by Matthew Walker, and it reminded me of how important sleep is, and how devastating sleeping just a little bit less than what we need can already be. As a mom of a toddler who still doesn't sleep through the night, it's difficult to prioritize sleep - but I've been making sleep more of a priority. Sleep now wins over working my split shift.



To know who else is "with me" on this, and makes sleep a top priority, I ran a poll (and as I mention in the wake below, I've started setting an alarm at night to go to bed - which is so far not always a success, but I'm working on it!):

PhD Talk for AcademicTransfer: How to select the right journal for your work

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!

If you are at the point during your PhD trajectory or beyond when you feel ready to start preparing your first journal article, you need to select the right venue to submit your work to.

Editors comment that a lot of desk rejections can be avoided by properly selecting a journal. Today, therefore, we will focus on the topic of selecting the right journal for your work.

When should you select where to submit your work? Ideally, before you start writing your article. As such, you can tailor your article to the audience of the journal, write directly into the right template, and keep the word count limitations of the journal in mind when outlining and preparing your work.

So, what should you consider when you select your target journal? Here are a few elements to consider:

1. Scope
First of all, you should always check the scope and aims of the journal. If your work doesn't fit the scope of the journal, you're headed for a straight desk rejection. If you're not sure if your work would fit the journal, then check a few back issues to see which topics are typically covered by the journal. If you don't know which journals to check first, start with the journals you read and in which work similar to yours has been published. As such, you'll get a pointer on where to start.

2. Audience
Another important topic to keep in mind when you select a journal, is the audience. When the journal is printed and managed by a learned society, the audience will be members of this society. For journals in the hands of commercial publishers, the audience may be a bit more difficult to determine. Try to learn who reads the journal: only academics, or practitioners as well? Is it read internationally, or is it oriented towards a specific region? A number of journals in my field are US-oriented, whereas others may be more European or international. When you know the audience, you need to write for your audience. For example, when the audience of the journal includes practitioners, include recommendations for practice.

3. Review timing
Do you need a journal paper in review or accepted as a requirement for graduation? In that case, it may not be a good idea to submit to a journal that has a very slow review process. Some journals take up to a year to return review reports. Check the time to review on the journal website - most journals nowadays display this information on their website. If the information is not available, ask your senior colleagues about their experiences with this journal.

4. Reputation
I don't subscribe to the idea that publishing in a high impact journal says anything about the quality of your work. Moreover, the impact factors depends on your field of study, so it does not create a level playing field. For example, the impact factor of journals in concrete material engineering tend to be higher than those of structural concrete. Saying that one field is more important or better than the other, of course, is utter nonsense.
However, when I mention reputation here, it is closely related to the audience: who reads the journal? Do people get the journal ever (other) month by mail? Or do people tend to read the articles online, and only the articles of interest?

5. Open access
Are there requirements from your funding body to publish all your work open access? Are there initiatives at your university that support open access publishing? If you have identified an open access journal, what is the APC (article processing charge)? Who pays for it - you, your funder, or your university? If not your funder or your university, can you apply for a waiver with the publisher? Can you do something else to reduce the APC? Some journals give vouchers to reviewers to get a discount on the APC.

6. Beware of predatory or hijacked journals
In the dark underside of academia sit predatory and hijacked journals. Have you ever received an email of a journal that says they want to publish your work? Sometimes even an email from a field completely different to yours, and maybe an email with spelling errors (or comic sans ms as their font)? Red flags to identify a predatory journal. Hijacked journals are even more sneaky - they tend to use a name that is almost the same as the name of reputable journal, and their only goal is to cash in on the APC.

I am Ayesha Scott, and This is How I Work

Today, I have the pleasure of interviewing Dr. Ayesha Scott. Dr Scott joined the AUT Business School, Finance Department in October 2016. She obtained her PhD in Financial Econometrics in July 2016 from Queensland University of Technology (QUT), Australia, and has undergraduate degrees in Mathematics and Finance. She is an interdisciplinary researcher, with an agenda that spans violence against women, empirical finance, personal finance and financial econometrics. Her work (particularly on KiwiSaver and personal finance) has generated media interest within Aotearoa New Zealand, and you will find her commentary in outlets such as the NZ Herald and stuff.co.nz. Passionate about healthy financial relationships, Ayesha has ongoing projects exploring the impact of financial and economic abuse in the context of intimate partnerships. This is a critical social issue that must be addressed in NZ and internationally, and her current work aims to give voice to women facing this evasive, invasive and poorly understood form of intimate partner violence.
Ayesha is also interested in the personal financial literacy and capability of New Zealanders, including vulnerable populations, and how we might improve the financial fitness of individuals. Poor financial literacy (knowledge of financial concepts) and capability (the ability to use that knowledge to make better decisions) has a significantly negative social and economic impact on a nation, both in terms of the macro economy and individual welfare.

Broadly, her doctoral research focused on the volatility and correlation dynamics of financial assets such as stocks. The near-continuous flow of price and trade data of financial assets presents researchers with opportunities, as well as unique challenges, to capture the return dynamics of these assets individually and as a group. Such models may lead to insights regarding optimal portfolio allocation decisions, information that will directly benefit investors.”

General:
Current Job: Senior Lecturer – Finance (equivalent of Associate Professor in the US system) at Auckland University of Technology
Current Location: Auckland, New Zealand
Current mobile device: Samsung J-series – don’t ask me what model. Not the most recent one!
Current computer: Work provided HP Elitebook

Can you briefly explain your current situation and research to us?
I am a permanent academic faculty member (equivalent of a tenured Associate Prof in the US system), mother of two children (7 and 5 years old – yes, I had them during my PhD) and my husband is the primary carer. My secret weapon is without doubt the support of my husband, who works part-time at the kids’ school, and is otherwise a stay-at-home dad.

My research is eclectic. I have projects spanning intimate partner violence, personal finance, empirical finance, corporate finance…the project closest to my heart is financial violence, which is the use of money as a weapon against a romantic partner. Predominantly gender-based violence, financial and economic abuse (financial violence) has devastating consequences on families, and my work is focussed on theorising solutions, raising awareness and telling the stories of survivors.

What tools, apps and software are essential to your workflow?
For planning (aka keeping ALL the balls in the air): My bullet journal and Microsoft Outlook calendar
For writing: Word or Scrivener, depending on the project and team
For storage: OneDrive/Dropbox, depending on the collaborator
For data analysis: Matlab, Stata or NVivo, depending on the project
For music: Spotify

What does your workspace setup look like?
Ha! Messy! I am in a perpetual state of flux for this one. I do the work primarily from my office on campus (photo below), because I adore having a double monitor with the option of a third if I open my laptop screen (in the photo this is being used as additional desk space). What you can’t see is the bed, couch and home office I work from at home, the yoga mat in my campus office when I want to lie down and read, or the pile of random paper on a chair behind my desk chair that is my quick version of ‘tidying’ my desk. This ‘tidying’ helps my desk stay relatively operational, and I can’t see the mess 😉
The wall behind my computer monitor is covered in art from my kids, photos of those kids, thank you cards and inspirational quotes.



What is your best advice for productive academic work?
Do what you love. I have been extremely fortunate to land in a department at a university in a country that supports research that matters, and I have been able to transition from a solely quantitative researcher (my PhD is in Financial Econometrics) to a qualitative researcher focusing on personal finance and financial violence in romantic relationships. In an environment where everything we do is judged (students grade our teaching, peers review our research) and we face a ton of critique and rejection, it makes productivity much easier when you believe in the work you are doing.

How do you keep an overview of projects and tasks?
Lists, both handwritten and digital – I keep a bullet journal and schedule EVERYTHING in my calendar. As I go through my day, I update my calendar to reflect how long tasks actually take so I can adjust my expectations in the future. In terms of longer-term goals, I set weekly goals that build toward my semester/quarterly goals.

Besides phone and computer, do you use other technological tools in work and daily life?
I use a dictaphone if the words/ideas aren’t flowing and firmly believe when typing and talking don’t work, a pen and paper will help. An external hard drive automatically backs up my work while I’m sitting at my office desk.

Which skill makes you stand out as an academic?
I would love to put “professional dot connector” on my CV! Seriously, I enjoy building quality relationships with people and believe this is a skill that allows me to work efficiently and effectively across teaching, research and service.

8. What do you listen to when you work?
Spotify’s Morning Motivation playlist gets me through admin tasks, email and teaching prep, if I’m writing then something instrumental. I do try to branch out occasionally, but quickly realise I am a creature of habit! If I’m working on something in particular, I have been known to play one song on repeat.

What are you currently reading? How do you find time for reading?
I have been on a personal development binge this year, and just finished Atomic Habits by James Clear and The Bullet Journal Method by Ryder Carroll. I rarely read one book at a time, I have at least two on the go at any one time. In terms of finding time, I have prioritised my mental health this year and part of that is making myself read non-academic work. I listen to audio books on my walk to work (30 minutes) and read before I go to sleep.
In terms of fiction, I adore romance novels – these tend to be quick reads for me and are pure escapism.

Are you more of an introvert or extrovert? How does this influence your working habits?
I’m an omnivert, for sure, meaning I am 50/50 and it depends on the situation, but as I get older I am becoming more introverted. I teach on large courses, meaning in a given week 650 undergrad students have access to me, not including my teaching team and postgraduate students. To protect my energy, I either wake up early and leave the house before my kids are up and about, or sleep in and cuddle them until we all have to get moving. Whichever happens, the first two hours of my day has to have quiet!

What's your sleep routine like?
I aim for 8 hours and probably get 7.5 on average. I really like getting to sleep before 10 pm and try to wake early (before 6 am), but this is a continual work in progress…I don’t make myself get out of bed before 7 if I’ve had a rubbish sleep, unless I have an appointment early.

What's your work routine like?
Coffee (yes, this is work!), check in with my bullet journal, research if a non-teaching day, teaching prep or meetings if a teaching day – I would love to be one of these people who doesn’t check email until 12noon, but it is unrealistic for me as I have things crop up organically that can take a day in a different direction (research students are great for needing help at random times – and I have an open door policy). I also don’t try to force myself to work on a project if I simply am not feeling it, my energy is sometimes best directed at something different.
I do try to lump my meetings onto teaching days, to try and retain big chunks of time for research days that are flexible. Not always possible, but I try!

What's the best advice you ever received?
That academia is the best job in the world – use the flexibility to your advantage. I’m not sure I do this as well as I could, but it is something I am striving for.

Optimizing Finite Element Models for Concrete Bridge Assessment With Proof Load Testing

My colleagues and I recently published a paper "Optimizing Finite Element Models for Concrete Bridge Assessment With Proof Load Testing" in Frontiers in the Built Environment - Bridge Engineering for the Research Topic Diagnostic and Proof Load Testing on Bridges.

The paper is Open Access and can be accessed here.

The abstract is
Proof load testing of existing reinforced concrete bridges is becoming increasingly important as the current bridge stock is aging. In a proof load test, a load that corresponds to the factored live load is applied to a bridge structure, to directly demonstrate that a bridge fulfills the code requirements. To optimize the procedures used in proof load tests, it can be interesting to combine field testing and finite element modeling. Finite element models can for example be used to assess a tested structure after the test when the critical position could not be loaded. In this paper, the case of viaduct De Beek, a four-span reinforced concrete slab bridge, is studied. Upon assessment, it was found that the requirements for bending moment are not fulfilled for this structure. This viaduct was proof load tested in the end span. However, the middle spans are the critical spans of this structure. The initial assessment of this viaduct was carried out with increasingly refined linear finite element models. To further study the behavior of this bridge, a non-linear finite element model is used. The data from the field test (measured strains on the bottom of the concrete cross-section, as well as measured deflection profiles) are used to update the non-linear finite element model for the end span, and to improve the modeling and assessment of the critical middle spans of the structure. Similarly, an improved assessment based on a linear finite element model is carried out. The approaches shown for viaduct De Beek should be applied for other case studies before recommendations for practice can be formulated. Eventually, an optimized combination of field testing and finite element modeling will result in an approach that potentially reduces the cost of field testing.

Feasibility of Collapse Test on Nieuwklap Bridge

My colleagues and I published a paper in the BEI (Bridge Engineering Institute) Conference proceedings. In the end, none of us could make the trip to the conference, even though I had originally co-organized a mini symposium in this conference about field testing. I couldn't figure out childcare, my colleague didn't receive his visa, so in the end we couldn't give our presentation.

Nevertheless, here is the abstract of our paper:

The Nieuwklap Bridge is a 7-span reinforced concrete slab bridge that is scheduled for demolition. Since a large number of reinforced concrete slab bridges in the Netherlands are found to have insufficient shear capacity upon assessment, such bridges have been studied extensively over the past decade. To better evaluate the structural behavior and ultimate capacity of slab bridges, it was suggested to test the Nieuwklap Bridge to collapse. Since collapse tests are expensive and involve large risks, an extensive feasibility study is necessary. Testing of the Nieuwklap Bridge would be interesting if the assessment shows that the bridge is representative for the shear-critical slab bridges in the Netherlands, and if the test can be carried out safely. An assessment of the bridge in an end span and middle span at two levels of approximation is carried out, and the maximum load required to cause collapse is estimated. The outcome of the feasibility study is that the required loads for collapse are large when a plasticity-based model is used. Furthermore, the Nieuwklap Bridge is not shear-critical and thus not representative of the shear-critical slab bridges in the Netherlands. As such, collapse testing is recommended against.

Interviewing and Hiring Practices in Brazilian Academia: Proposals Towards Improvement

My coauthors and I just published a paper titled "Interviewing and Hiring Practices in Brazilian Academia: Proposals Towards Improvement". It's open access, so you can read the full text here.
You can read my blog post about the preprint here.

The abstract is:
Though Brazilian academia claims equality, the sector has largely been referred to as non-meritocratic, and academic hiring is still inward-oriented. The Lattes platform, a public curricular information system, reflects elements of this protectionism. This article assesses two ‘obsessions’ in Brazilian academia: the ‘mandatory’ Lattes CV, and the assessment criteria and procedures in public tenders for faculty positions. The current situation is introduced to the reader, and the shortcomings of these methods and their effect on academia in Brazil are analyzed. The following improvements are proposed: (1) evaluations in public tenders based on a candidate’s CV, interview, and a sample lecture, (2) removing the Lattes CV as a mandatory format, and (3) using platforms such as Microsoft Academic, Google Scholar, ORCID or ResearcherID for curricular information. With these recommendations, Brazil can move towards a more open and international-oriented academic hiring system.