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IStructE Lecture - The Millau Viaduct

15 October, 2008 (20:37) | General | No comments

Dr Vincent de VIlle of Bureau Greisch de Liège gave an enthralling lecture in DIT Bolton St last night about the design and construction of the MIllau Viaduct (emblazoned on this website). The Millau Viaduct, completed in 2004, has already taken its rightful place as an engineering masterpiece and this was reflected in the turnout for the lecture. Over 150 people attended - one of the highest attendances ever for an Institution of Structural Engineers, Republic of Ireland Branch, Evening Meeting. The lecture left even experienced engineers breathless as Dr de Ville explained the many bold decisions made in both the design and construction of the deck. Indeed he made designing for 5 m deflections during construction seem reasonable!

The lecture was certainly one of the best seen here in recent years. Dr de Ville modestly claims that the subject matter is the reason for success. However, the way in which extremely complex structural engineering ideas were conveyed meant that even the lay-people that attended were able to follow and enjoy the excitement of this design. The lecture reinforced a pride in structural engineering, and the accomplishments that are possible given a bold vision and adequate resources.

Some relevant links to this talk are:

Avoiding Semester 1 Syndrome

19 September, 2008 (20:22) | General | No comments

Let’s do this in FAQ fashion. But first be aware that some generalizations and personal opinions follow…

What is the Semester 1 Syndrome?

Simply put, it is the tendency for students, fresh into 3rd year, to put an inadequate amount of work in, and who consequently don’t perform as well as they wish.

Have you any evidence for it?

Yes from experience. Semester 1 exam results tend to be quite poor, with a high number of students having to resit the exams. Surprisingly, 9 months later, with no further classes in the subjects, students generally improve their marks significantly, sometimes by over 60%. That’s the Semester 1 Syndrome!

As an aside, many lecturers give individual feedback, without the “I’m being assessed” feel to it. Interestingly, in the majority of cases, such feedback correctly predicts whether students would pass or not. I think the moral is, when given personalized and informal feedback well in advance of any assessment, please act on it!

Why does it happen?

This is complex but the probable answer lies in the way that the students have ‘engineered’ exam success up to the point of arrival in 3rd year. Unfortunately the Points System and Leaving Cert. encourage a learn-by-rote model as being optimal for exam success. The first two years in third level can be approached in the same way, but it gets increasingly difficult. The failings of this learning model come to a head in 3rd year when the material that must be known is minimal - extensive exam handouts mean that little memorization is required. Instead, the material must be understood. Simple really, but since this is the first time students may actually have to try understand material for exam success, it poses a real difficulty and a harsh awakening in many cases. And by understood, we mean that the material is second nature and that disparate pieces of information can be assimilated into different coherent forms so that reasonably complex engineering problems can be solved.

Ok, so how can it be avoided?

Well I’ll bet you know the answer to this, in the same way you know that you should eat more fruit and vegetables. For every hour spent in class, at least another hour must be spent at home doing the following:

  • assimilating the material already covered;
  • reading ahead on the new material;
  • practicing examples until exhaustion (!);
  • preparing questions to ask the lecturer in the next class;
  • studying with colleagues - peer-learning is very effective.

Last year a quick class survey noted that over 90% of students had part-time jobs during term-time. In a week, it is simply impossible to spend say 30 hours in class, another 30 hours of home study, and then do a job. It seems that for short-term gain (i.e. some extra money now), the longer-term benefits of performing well in college are ignored. These longer-term benefits include improved employment prospects and the possibility of a higher starting salary for 1st class and 2:1 Honours Degree awards. It’s called full-time education for a reason!

One further issue that can significantly affect performance is the abuse of alcohol amongst 3rd level students. A recent study summarized here and fully reported here shows that use of alcohol is increasing amongst undergraduate students. This can only have a negative affect upon coursework. Whilst certainly the college experience is not all about hard work and learning, going too far the other way is not a recipe for success or happiness. If you or a friend is affected by alcohol abuse you should contact the student counselling service.

More on presentations

3 September, 2008 (00:51) | General | No comments

In the Presentations section of the site I’ve mentioned Edward Tufte and the art of presenting complex information. He even suggests that PowerPoint was complicit in the Challenger disaster due to its inability to convey complex information. Read an extract from his essay The Cognitive Style of PowerPoint: Pitching Out Corrupts Within here.

Anyway, the following site takes a funny look at presentation of a difficult dataset, showing the common (and very poor) method, and a good method:

Red-shirt fatalities in Star Trek

Journal article published

1 September, 2008 (13:52) | General | No comments

The paper titled Determination of bridge lifetime dynamic amplification factor using finite element analysis of critical loading scenarios will appear in the September 2008 edition of Engineering Structures. This journal has an impact factor of 0.986 for 2007.

This paper outlines the simulations behind the dynamic interaction model which was used in the bivariate extreme value work, detailed here.

The full reference for this paper is:

Gonzalez, A., Rattigan, P., OBrien, E.J. and Caprani, C.C. (2008), ‘Determination of bridge lifetime dynamic amplification factor using finite element analysis of critical loading scenarios’, Engineering Structures, 30(9), September, pp. 2330-2337. http://dx.doi.org/10.1016/j.engstruct.2008.01.017.

Abstract

The development of accurate codes for the design of bridges and the evaluation of existing structures requires adequate assessment of heavy traffic loading and also the dynamic interaction that may occur as this traffic traverses the structure. Current approaches generally first calculate the characteristic static load effect and then apply an amplification factor to allow for dynamics. This neglects the significantly reduced probability of both high static loading and high dynamic amplification occurring simultaneously. This paper presents an assessment procedure whereby only critical loading events are considered to allow for an efficient and accurate determination of independent values for characteristic (lifetime-maximum) static and total (including dynamic interaction) load effects. Initially the critical static loading scenarios for a chosen bridge are determined from Monte Carlo simulation using weigh-in-motion data. The development of a database of 3-dimensional finite element bridge and truck models allows for the analysis of these various combinations of vehicular loading patterns. The identified critical loading scenarios are modelled and analysed individually to obtain the critical total load effect. It is then possible to obtain a correlation between critical static load effect and corresponding total load effect and to extrapolate to find a site-specific dynamic amplification factor.

Randy Pausch Dies

30 July, 2008 (15:47) | General | No comments

Randy Pausch, a computer engineering lecturer from Carnegie Mellon University has died. He became kown for his Last Lecture wich has been viewed by over 6 million people on video and was turned into a book - The Last Lecture, which is how I came to know him.

He was diagnosed with Pancreatic cancer and following this gave his Last Lecture. He survived way beyond the 3-6 months given him by medics.  The book and lecture are moving and very memorable and leave you with a desire to achieve your childhood dreams. Well worth reading or viewing:

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