I took 15 minutes and drew a long span slab bridge (My deck is 2 feet thick.). I read the Happy Pontist article on granite slab bridges and I wondered how long and thin you could make a concrete slab with some prestressing strands. (concrete has a weight about 150 lb /cu.ft while granite is around 165 lbs/cu. ft.)
You can manufacture 30,000 psi concrete (expensive) and it should be more uniform and just as long lasting as granite. (Maybe? I would be worried the granite is not uniform in strength over its length.)
Anyway this is a “quick” play bridge. I am thinking I will have to make prizes if I have a bridge competition…
I am sitting around while another student has a go at my first exam. So I thought I would post a River Bridge competition for myself and anybody else who is bored…
I drew up a quick sketchup river section with two concrete abutments. The abutments are spaced 110′ feet apart on center and would accomadate a 10′ wide pedestrian bridge. (I wanted a quick template to try out some bridge ideas.)
I thought I would throw out some names from the web, to get started. ( in no particular order.)
Updated: The Happy Pontist has suggested some more prominent bridge engineers for my list. I have to admit (sheepishly) that I don’t know many of them…but I am learning! The list with random links for each engineer.
From my quick survey of the room I think everybody is using a TI calculator. Nobody seems to have the George Bush or HP calculator. (Ya know expensive and does math backwards, HA!, thats right I said it.) I’m getting loopy.
Seriously is a TI calculator really worth a $160 bucks? (about two euros or kilo-dollars) I used to program my calculator with buckling formulas and I even bought the Ti Voyage, which broke down in three months.
I have a grad student helper here and he thought he found a mistake in my exam! Yikes too late to change it. Frantic computering ensues…
Not to worry false alarm, me and STAAD check out….
I am sitting in a large windowless classroom as 63 students take a two hour structural analysis test Although it is -10 outisde it is +80 inside. (415 C to you metric types. You think your sooo cool with your kilo this and centi that, who really needs a worldwide standard anyway. Who says we need to design to a millimeter and not 1/16″. It was good enough for the Viking/pilgrams and it is good enough for me. Whoa sorry I getting heatstroke here..)
So I have to have a question and here it is, how do you design a test that gives the majority a chance to pass while challenging the keeners. (Canadian term for cool guys or was that nerds?) AND a test the course leader doesn’t hate and eventually uses for his class…
Oh oh is that guy cheating :(. Hey put down the iphone. Yes I’m talking to you, the one in the red shirt.
We teach a method called “Visual Integration” as well as the typical virtual work method for finding deflections of beams and frames. I did the math and it seems like a simpler system than integrating moment equations. (See video for lousy half-asleep explanation. tomorrow is our first big test!)
I was wondering if a) people teach this and b) does anybody have a reference for this method? (I have never seen a textbook with this method maybe it is sooo simple everybody knows it. Maybe its called something else? I can derive the method…..)
Let me know if you were taught this method, thanks!
Is this real? If the bridge is real, it is an amazing structure…..I am trying to figure out how you would build it.
Here in the frozen tundra, we are anxiously waiting for spring. (Or any temperature above freezing..) Tomorrow night I give my first exam. When I first started teaching I had a class of 20 and gave tests during class. Now with 55 students I have to give night exams from 8-10. I’m too old to stay up that late! Oh well on the bright side, it is supposed to be -4 tomorrow night…..
This is about the time in the semester where I question my sanity over working two jobs. The initial excitement of a new class has worn off and I am in the grips of virtual work for deflections. A popular question from the students is “why do we need to know this…”.
Last fall I tried to enter the Calgary Pedestrian bridge competition. It was an open competition where anybody with access to a copy machine could enter. (You had to submit multiple copies of your design and I just did not have the time…so disqualification!)
Looking back, I have gained a sense of how rare an event this turned out to be. Since I had never traveled on the competition circuit I did not realize that competitions open to the public and ENGINEERS were not in fashion. (I have been watching the “Death by Architecture” website for another opportunity but nothing yet…read the Happy Pontist about his views on competitions)
Engineers seem to hate the idea of an open competition. Maybe it is not possible to submit ideas that we know we cannot build for the budget. Maybe engineers have so much work we really don’t have the time for competitions? Maybe we are not trained to compete and withstand a withering critique of our design in the press….
I sometimes feel the lack of competitions confine our discipline and stifle (think Archie Bunker) innovation. Without something pushing our backsides I doubt engineers are motivated to change. Maybe competitions would help bring engineers back to the front of design?
An old article on wired.com lists the top five reasons it sucks to be an engineering student. I have to agree with most of them and after my lousy performance today as an instructor…I agree with number 4. I am encouraging but I had a crap lecture today…hey its hard to bring your “A” game everyday!
4. Professors are Rarely Encouraging
During each class, a professor that would rather be tending to his research will waltz up to a blackboard or overhead projector and scribble out equations for an hour without uttering a single sentence to create some excitement.
Got sent this…..look close, they give a shout out to bridge engineers!
To the editor:
Feb. 14-20 is National Engineers Week. Every year during this week, engineers take time to celebrate the collective accomplishments of our profession.
Over the past 150 years, the engineers in this country have played a significant role in such accomplishments as construction of the transcontinental railroad, manned space flight, cellular phones and personal computers. Engineers are doers who turn ideas into reality.
Engineers are changing the world all the time. The manmade environment and the quality of life we enjoy in this country were made possible by engineers.
By the time we reach the middle of this decade, the demand for engineers in this country will be unprecedented. By an American Society of Civil Engineers estimate, billions of dollars in engineering and construction will be required to renovate and upgrade our existing infrastructure.
Engineering expertise will be required for development of new medical diagnostic equipment to building more energy-efficient cars and trucks to creating new means of constructing buildings and bridges to resist the ravages of an earthquake to cleaning up the environment. The challenges that lie ahead are daunting, and continued leadership in engineering and technology are critical to the future of this country.
Engineering has been called an invisible profession, but everything that we use has been touched by an engineer in some way. We take great pride in this fact. So, if you woke up this morning in a warm house, drank a clean glass of water, talked to a friend on a cell phone, drove your car on a paved road over a safe bridge or turned on your personal computer and checked for e-mail messages, thank an engineer.
I remember the stories of engineering prowess back in school. Like removing all the bolted desks from a classroom or building a car in a lecture hall. So I think I need a segment about things only engineers would do….like this. I’m sure everybody has a story they can pass along.