So time for some shameless promotion for my wife, Kori.
Like a lot of engineers, sitting all the time, I gained a little unwanted weight. Plus, as an older guy I started losing muscle tone. (Lifting a pencil does not build the biceps!)
So my super fit wife, a microbiologist by training, and a BeachBody coach jump started me back into fitness. Right now I am lifting weights with her and the BodyBeast AND doing Insanity workouts.
Kori is a certified trainer in Insanity, P90X and Turbo kick!
Right now I go to her Insanity classes and collapse, but in a good way. I have to say lifting weights and having a trainer help you get in shape is amazing.
Anyway, if you live in the United States or Canada, want some help getting in shape or want some guidance on tools to get in shape, contact Kori here:
Contact Kori – BeachBody Coach
Contact Kori – BeachBody Coach
So you want to be an engineer, can you pass the test?
David sent some great links on the Gladesville bridge in Australia.
Gladesville Bridge: The span of the bridge is 300 m (1,000 ft) and at its highest point gives a clearance of 60 m (200 ft)
Gladesville Bridge is an arch bridge that spans the Parramatta River, west of central Sydney, Australia. It is a few kilometres upstream of the more famous Sydney Harbour Bridge. At the time of its completion in 1964, Gladesville Bridge was the longest single span concrete arch ever constructed. Gladesville Bridge is the largest of a complex of three bridges, including Fig Tree Bridge and Tarban Creek Bridge, designed to carry a never built northern expressway.
Here is a film of the construction, it is amazing how far (or not) building techniques have advanced.
And check out all the safety rules that are broken, people riding in precast, no hardhats and no safety lines. My favorite is the guy with the red sweater casually wrapped around his shoulder walking on top of the arch. (Time 14:09)
Most engineers have heard the saying “garbage in-garbage out”. It was a phrase developed for software engineers, meaning, if you enter garbage data into a software program you will get garbage out.
I Ike the modified version of “garbage in-gospel out” because it reminds me the output I get from my structural analysis program is only as good as the assumptions I enter into the software. Too often we believe the computer print out as being “gospel” or the absolute truth.
There used to be a school of thought that mandated an engineer only use software that he or she created. That way the engineer would know all the limitations of the software and account for unknowns with a little more conservative design.
Why do I bring this up, well, I had a meeting today about camber in prestressed pretensioned concrete beams. Specifically about how to get closer to the “actual” camber deflection dimension.
The problem in determining camber for long PPC beams is knowing the exact concrete mix properties and the initial and 28 day concrete compressive strengths. Without this information they best you can do is approximate the beam camber and use methods in construction to account for variances.
But you don’t necessarily have this information when you design the beam and prepare the bid documents, months before a letting.
Precasters typically use hot mixes (strengths about 20% above the design strength) so they can pour beams and strip them in a one day cycle. Quick turn arounds mean more money but cause me some problems in my design.
Say I ask for 7000 psi initial strength but I actually get 10,000 psi from the factory. Fine by me, but here is the point. Don’t ask me to calculate a beam camber within 10% of the actually camber based on my design strength of 7000 psi. Either live by the limitations of such a system with some realistic error bars or readjust the camber numbers after the beam strengths are known. (Not blaming precasters, I used to be one)
You cannot get accurate camber numbers out from a computer program unless you put accurate strength numbers in, so realize that and live with the fix in the field.
Otherwise, GIGO. See I got there.
I was watching this video and thinking if engineers designed this it would be square and have very small windows.
Maybe a rating system, like LEED, would spur momentum in the bridge industry? I know a number of organizations are trying to get one into the infrastructure marketplace. ASCE has Envision, the FHWA has Highways for Life, and the Illinois DOT has the I-Last system.
Maybe it would help if we competed for points?
I had a couple of guest lecturers today and they spoke about LEED.
LEED, or Leadership in Energy & Environmental Design, is transforming the way we think about how our buildings and communities are designed, constructed, maintained and operated across the globe. Comprehensive and flexible, LEED is a green building tool that addresses the entire building lifecycle recognizing best-in-class building strategies.
At its core, LEED is a program that provides third-party verification of green buildings. Building projects satisfy prerequisites and earn points to achieve different levels of certification. Prerequisites and credits differ for each rating system, and teams choose the best fit for the project. Learn more about LEED, the facts, and the LEED rating systems.
Now engineers have been looking at such a system for infrastructure projects but what do they (we) get stuck on, well cost of course.
It is time to free our minds and start with the idea that costs do not matter, results matter. Now I’m not advocating losing our senses but in class the thing upper most in the mind of my engineering students, concerning LEEDs, was the cost.
We need to get past cost and get with the program, namely any program that moves our industry forward in a similar manner to LEEDs. A program that sparks innovation, competition and environmental expediency.
Green bridges, green roads, we need them now, time to get with the program.
From Global Footprint Network
Today humanity uses the equivalent of 1.5 planets to provide the resources we use and absorb our waste. This means it now takes the Earth one year and six months to regenerate what we use in a year.
I have been “writing” this blog for a good number of years now and once in a while I like to survey the landscape and see what is out there. By out there, I mean, other engineering blogs.
The Happy Pontist remains the gold standard for a well written sometimes acerbic take on bridges throughout history. The one fault I have with HP, entirely my own preference, was the desire that he or she had their name on the masthead. I would like engineers to have some role models, of which, HP is a very good one. But I do understand the nature of wanting to keep one’s, day job.
So, I went forth and typed in “Bridge Engineering Blog” into the google and found that a) bridge blogs are hard to find (written by actually bridge engineers and not corporations) and 2) that I had written this exact post in 2009.
At that time I also pondered the lack of engineers out there discussing their work. I, of course, realize the blog is dead and now vine, Instagram, whatsapp (quit writing me by the way, stupid 19 billion) and others are the way to go.
So, what to do. I guess I should be proud that I am one of the top ten bridge blogs written by an actual bridge engineer. (I made that statement with a number of fingers crossed, made it tough to iPad. Since I doubt there are more than ten blogs out there, I should be in the top ten.)
Oh well onward and upward, now here is a picture of a cat. You have to feed the internet….
Great watercolor demo from Joseph Zbukvic.
This is a review I received on my Structural analysis example kindle book. (Link on the right)
Seems very fair and exactly what I was going for…..thanks PDC for the review!
4 out 5
I’m a practicing structural engineer and bought this as I thought I could review some examples of problems in structural analysis. It is, in essence, basic structural analysis (the word “introductory” probably should’ve given it away, huh?). Most problems are likely problems from Nielsen’s texts that he’s used over the years, minus the commentary. There’s probably some additional problems in here as well, but there is very little in-depth commentary or explanation or complicated examples.
I wouldn’t recommend for someone trying to learn the material, without the addition of a course text. On the other hand, it is likely a decent source to go hand-in-hand with someone taking the course or who has the knowledge of structural analysis. All in all for $1.99, it’s a good review text.
A sorta quick introduction to PowerPoint animation.
Sometimes the video will not play in HD on a mobile device, so go to my youtube account for better quality.