I’m pleased to say my implementation of the Nelder-Meade Simplex Algorithm (on my C++ page here) was able to optimize it for each minima (depending on the starting locations of course). I did have a weird problem though – starting a solution at (0,0) failed, even though the minima are not equidistant from the origin. Go figure!

Candidates interested in pursuing PhD research in Bridge Loading: statistics and dynamics should send a CV to info@colincaprani.com.

Candidates interested in self-funding research to MSc level are also invited to send their CVs.

Again, some motivation is given in the chart below, and in this post.

The Worst Bridge Collapses in the Past 100 Years

Mianus Bridge, Greenwich, Conn. (June 28, 1983)

Another collection is here:
http://www.environmentalgraffiti.com/news-seven-quaking-bridges-collapsed-costing-lives

For details of the bridge and the test set-up, see here:
http://nees.unr.edu/4-spanbridges/UNR Web AnnouncementCompositeBridge.pdf

and the link for the webcast is:
http://nees.unr.edu/projects/4span.html

Four Span Bridge Test

The program is the main point of interst though. For your design, it animates in real time the stresses and member failures that occur as chosen loads traverse your bridge. The graphics are cool and there isn’t too much by way of technical input data required. Prepare to lose some hours playing this though!

West Point Bridge Designer 2010

A funny bridge design is here:

Joking aside though, we visited three incredible structures/displays. The first was BMW Welt, which is a hugely architecture-driven structure with an amazing floating walkway through the space. BMW Welt is worth the visit just for the displays of automotive technology. Even though we’re not mechanical engineers, I think the basic engineering of complex systems still appealed to us.

BMW Welt

The main visit of the trip was to the Olympic Site of 1972 where Frei Otto‘s work still amazes. This is all the more so, because before computer models, there were…

Physical Model of Olympic Roof

physical models. The level of detail on this model is incredible – even down to little weights at particularly heavy connections. Of course the attention and detail put into this physical model should be replicated in any comparable computer model. However, we were told that the results of the computer model of the time arrived two years late and said that the structure wouldn’t work. Well it’s still there, so 1-0 to physical modelling!

Some inspired students!

The most amazing feature of this structure is the clarity with which you can observe the flow of forces around the structure:

Equilibrium creates its own form

The last visit was to the Deutsches Museum – one of the world’s largest museums dedicated to science and technology. In short: a nerd’s paradise. It was great! We spent an afternoon there and only had time to cherry pick the exhibits of most interest to us. Unfortunately the highway bridge section is being refurbished, but it’s on the list for a revisit when it’s finished.

That didn’t detract though: all of the basic physics of engineering was on display, most exhibits were interactive also – lots of great ideas for bringing some of the fundamental concepts to life. One of my favorite exhibits is a back-lit transparent wrench covered in photoelastic film – you try to turn the bolt and you can see the stresses change:

Photoelastic wrench

There are many other fascinating exhibits like this for any breed of engineer or scientist. Highly recommended, but take more time than we did!

Lastly, it’s probably my favorite museum for one further geeky point: instead of a clock tower it has a…

Barometer Tower

Brilliant!

It was a great and sparkely trip: thanks to all involved, especially the Mammy and Daddy!

Produced by Arup for the Hong Kong Institution of Engineers 2009 Presidential Address.

Even though it’s been a long wait, Structural Safety is a well-reputed journal with an impact factor of 1.47 (2009) which is very high for a civil-engineering journal. The paper is available here, but may require a purchase if you don’t have an institutional login:

http://dx.doi.org/10.1016/j.strusafe.2009.09.001

Abstract
To assess the safety of an existing bridge, the loads to which it may be subject in its lifetime are required. Statistical analysis is used to extrapolate a sample of load effect values from the simulation period to the required design period. Complex statistical methods are often used and the end result is usually a single value of characteristic load effect. Such a deterministic result is at odds with the underlying stochastic nature of the problem. In this paper, predictive likelihood is shown to be a method by which the distribution of the lifetime extreme load effect may be determined. An estimate of the distribution of lifetime maximum load effect facilitates the reliability approach to bridge assessment. Results are presented for some cases of bridge loading, compared to a return period approach and significant differences identified. The implications for the assessment of existing bridges are discussed.

The full reference is:

Caprani, C.C., OBrien, E.J. (2010), ‘The Use of Predictive Likelihood to Estimate the Distribution of Extreme Bridge Traffic Load Effect’, Structural Safety, Vol. 32(2), March, pp. 138-144. http://dx.doi.org/10.1016/j.strusafe.2009.09.001.

Infinity Footbridge, Expedition Engineering Ltd.

The other awards are outlined here and are all fascinating examples of structural design.

If you are a student on an accredited civil/structural engineering programme, you should join the IStructE – it’s free! Click here to join.