Monthly Archives: November 2010

Strut and Tie in Concrete Design

The Happy Pontist, (who is always ahead of the curve) posted this comment,

I’ve used strut-and-tie fairly regularly, but generally for specific design problems such as corbels, or in assessment of existing bridges where it is sometimes the only way to prove that something can stand up safely. It wasn’t included in the UK bridge design codes, but is popular in parts of Europe and is in the current Eurocodes.

This got me to thinking about concrete design here in the states. AASHTO has been pushing strut and tie as the future design methodology but they have a lot of engineering inertia to overcome. It is a simple method, IF you develop the proper model. (which is true for the majority of engineering practice.)

I don’t teach Strut and Tie in my concrete class but now I think I have too! So this spring I think I will sneak it in….

Two Years!

It will be two years of blog posts this December! (I need to get a real life…) The quote below sums up the struggle of engineering.

From April 2009,

Check out this online book by Alan Holgate. It was originally published in 1986 but it has since gone out of print. It discusses the roles of engineers in design.

There is an old saying which goes something like this: “An engineer is a man who can do for a dollar what any fool can do for two.”

Its emphasis on ingenuity is praiseworthy, but it has been seen too often as a justification for much that is cheap and nasty in engineering.

It has been taken to mean that engineering is nothing more than the achievement of clearly specified technological objectives for the lowest possible cost in cash.

This view has been reinforced for engineering students by the fact that with a few notable exceptions, text books entitled “Design of Structures” are predominantly concerned with the techniques of computational analysis

Peace Bridge delays not my fault

From the Calgary Herald,

With the city announcing its controversial $24.5-million pedestrian span won’t be ready until June — eight months behind schedule — Santiago Calatrava noted his responsibility is for the design and not the construction schedule.

“We are not responsible at all for whatever are the delays,” he said in an interview from his New York office.

Check out some of the comments at the bottom, ouch.

Also a bridge I designed some 15 years ago……double ouch.

And one with piles! The bridge is in a sandy riverbed with lots of scour potential. Sooo lots of friction piles…that’s what they wanted..

Hulu short engineering films

www.Hulu.com has a few engineering videos online. (free with a couple of commercials) They are about 15 minutes long and have some good historical images. And all seem to be from the UK?

1) Fritz Leonhardt – The concrete needle

2) The golden gate bridge

3) The Empire State building

Update: Is this site available overseas? I seem to remember you need a “fake” IP to access the US Hulu site. Sorry if it doesn’t work.

Road layout

This video is one part information, two parts boring. Since I am not a road engineer the information presented may be wrong. Hows that for an endorsement of my own video?

I just wanted to show how a typically divided roadway was laid out and the video got away from me….

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Quick Introduction to Bridge Terminology

I made a quick, oddly disjointed video about bridge terminology. I’m not sure if this is helpful but as it often happens, I get a little bored and decide the “first take” is fine…

I thought I should discuss the elements of a typical bridge before I start laying one out in sketchup. Then I decided to add flood photos to the end for no apparent reason.

Quick Comebacks at work

I had a situation yesterday where I needed a good comeback in a meeting. I think I handled it pretty well but I tend to get mad instead of producing a snappy comeback.

The hardest part is being prepared and not being caught off guard. (It is also a fine line between going for the kill and losing your job.)

How about the rest of you, if you are insulted at work how do you handle it?

Wikihow has some pointers.

Providence River Bridge competition

Saw this on the Happy Pontist. I looked at the entries.

All the designs are cool but can they really be built for $2-4 Million?

I can’t build a 10′ x 450′  standard pedestrian bridge over a river for that price. Some of those concepts look in the neighborhood of $20-30 million…

I guess “X” marks the spot for money. (Or maybe it is a shamrock?)

TBG Video Podcast – making a stirrup in sketchup

I have not received any feedback on the video podcasts, which in my mind means they are GREAT! (It’s all about perspective.)

This is a quick sketchup video where I show you how to make a concrete shear stirrup and then I fly around a class project a little too fast. For those of you that get sick at amusement parks, well, you may want to avoid the second half of the video…

I also use a couple of plugins like, fillet.

(Note:It takes youtube a while to process the video so the quality will improve.)

Science and Engineering

Is science and engineering compatible? I’m not so sure.

This may be a terrible over simplification but pure science seems to look for answers not caring what answers are found. Gathering knowledge is the goal. Engineering seems hell bent on doing something with knowledge. Typically to solve a problem.

Or as Monty Python so aptly puts it ” Our experts describe you as an appallingly dull fellow, unimaginative, timid, lacking in initiative, spineless, easily dominated, no sense of humour, tedious company and irrepressibly drab and awful. And whereas in most professions these would be considerable drawbacks, in engineering they are a positive boon.”

Okay I changed it a bit. But here is a good article about the unease between scientists and engineers.

From Naturenews,

Science is mainly concerned with unearthing knowledge. Engineering seeks to deliver working solutions to practical problems in the form of technology. Yet the terms ‘engineering’ and ‘technology’ have been increasingly subsumed into ‘science’ — in the names of institutions, in discussion of ‘science policy’, in media coverage and in popular parlance. The situation upsets engineers and their leaders, but they tend to keep quiet for fear of being accused of having chips on their shoulders.

TBG Video Podcast 4 – Business card origami

So first an excuse, I am extremely busy! But I thought I should keep up with the video podcasts.
I had the idea to design a business card that can be cut and folded into a bridge. I got the idea here, for a card you can build. The video is rough, I used my wife’s flip camera and mounted it on a tripod but you get the general idea. I think my next video will be an introduction to bridge design using sketchup.