tallbridgeguy

Working on finding a formula to render a bridge fast with a reasonable outcome. This bridge took 15 minutes in sketchup and then about 1/2 hour in the rendering washing machine. It is about 150 meters long with a slight curve. Okay its lousy but it is teaching me about viewpoints and how to showcase a bridge.

The Calgary bridges will most likely be around 150 meters and 75 meters long. I will keep trying…

I have a working concept for my bridge design but now I face the problem of trying to get it developed/rendered in an award winning digital style. (Ha!) The first thing you notice when you try to do this by yourself is how much work it actually takes to get to an end product. As an engineer I have no formal training in developing presentation materials other than 2D CAD drawings.

From what I understand about architectural firms, they often have interns available, with computer skills, who can develop 3D sketches while the concept is being refined.  Take a look at this post at the Happy Pontist. It looks like Calatrava made some preliminary sketches for his bridge and then you see the fully rendered photorealistic final images. I doubt Calatrava develop the 3D renderings…The bridge images in that post are amazing. Is this the level of detail expected in the Calgary Competition? How many engineers can put something like that together?

I could use some help/suggestions on how to develop presentation materials. Maybe some pointers or some links to projects with graphics that even I could make, HELP!

I saw the first candidate for the new bridge on a forum at skyscraperpage.com It does have mountains, cowboys and a reference to the oil refineries in Alberta! (Ralph Klein was the mayor when i was living there)

The City of Calgary, in Alberta, Canada is having an open bridge competition for a new pedestrian bridge. The site is gorgeous and is a perfect location to showcase a bridge. The winner will certainly take a step closer to Calatrava status.

I want to enter the competition but my chances as a lone designer are not good. The Happy Pontist answered some of my questions about how to enter such a competition.

So ABC posts may become a bit sporadic while I tilt at windmills. I realize of course that I cannot possible develop a concept as deeply as a design team of architects and engineers. The allure of this project is the development of a new bridge concept, the design of something new.

So my steps to submission:

1) I have to decide whether to go extreme or practical. Since I am not going to win I think a “practical” design is out. I would rather be booted out of the competition for being too expensive instead of commonplace.

2) Since I am the Lone Designer, the concept is going to be vague. I can’t possibly develop digital quality renderings if I am worried about where the drains are going…

3) Rethink if I have the time for this…..still it would be fun to have my design in the mix.

One of the things about being an engineer is the fact you learn from experience. (Okay, everybody learns from experience.) What I mean is, once you start your career you start to see how things are done in real life situations. Designing something for a million dollars is vastly different than the plain straightforward examples you get in school.

Having a great engineer as a mentor is the ideal but most of us will learn from a variety of engineers with different levels of experience. To this end, I think a great deal about the “practical” advice I give my students in class.

For example, take the pier shown below. If the pier cap is longer than 60′ (typically the longest length of steel reinforcement that you would use in a bridge) you would have to splice the moment carrying (tension) steel reinforcement. I would probably splice the top steel in between the columns (TS), typically the lowest tension areas for the top steel and splice the bottom steel (SB) at the piers. (Typically the lowest tension area for the bottom steel)

Okay here is my question. If the top steel, at the splice point is always in compression (from your analysis of loads), would you use a compression splice or a tension splice? I would probably use a tension splice (development length) for all my splices, no matter if there is tension or not at that location. It is just easier and I know the tension splice is the most conservative option.

Now is this good advice for students?

I am working on a concept for a partial girder replacement. We do this when the hit portion of a steel girder is too damaged to heat straighten. I think of these fixes as franken-girders. Cut out the damaged T-section and bolt in a new section with as many bolts as possible. (get it frankenstein had bolts…)

I did a quick sketchup model, click on an image for a larger view. The red portion is the cut out section. (I don’t favor splicing the section in the positive moment region but sometimes you have no choice.)

Updated: I had to go out so this post needs a little more information. When you cut out a section of the bottom flange in the positive moment region you lose the carrying capacity of the girder. Which means the deck (and deadload) has to be supported by a strongback. (pic added below) The strongback typically spans from pier to pier and uses bolts (or rods) through the deck to take the weight off. I think four strongbacks would be the best if all the girders need new sections but you probably use one at a time. (sorry the first few pics are large…and look distorted unless you zoom in..)

Went to the state fair today. It was fun but hot. (Hey its my blog!) Next week I will write more about my partial girder replacement project.

As a bridge designer I am fairly confident that I can design a budget friendly, semi-attractive bridge. But as an engineer I am behind the curve in expressing new ideas or developing presentation materials to describe my ideas. That is why I am trying to learn software such as Sketchup, Photoshop and how to make presentation videos with Flash. (then again maybe I have bad ideas, and they should stay quiet.)

Architects have good ideas but they also have the training to present their ideas in visually appealing ways. (Think about how many engineering powerpoints you have sat through with nothing but bullet points and how passionate you felt about their work. )

When I walked through the Chicago Institute of Art, I saw great Art. I saw the painting “American Gothic” (should it be in quotes? Man I’m also lousy at writing, sigh) by Grant Wood. I thought, wow, nice painting. Not, the painting reminded me of the great depression and the trials of American farmers in working their drought stricken land. Art needs a story and so do bridges.

Calatrava spoke to the Calgary Herald about his motivation for the “Peace Bridge”. (whats with the quotes? )

“I wanted to do a very human bridge. A bridge that invited the people of one side to go into the other, and vice versa. Not only people who are jogging and so, but also regular citizens that take their bicycle and go for a tour in Prince’s Island or downtown. You see a mother with a child who push the small caddy. I wanted to do a very human bridge. I think that when   the bridge was explained to me, was explained as a connection between one part of the city into another one, in which many people will go to work also by using bicycles or whatever. And I thought it is necessary to do a very human bridge.”

I never would have explained a bridge concept in this manner. Although that is the goal I am looking towards, designing bridges that are more than just utilitarian. (okay engineers stop rolling your eyes…)

Okay its a slow day in the ABC blogging world. In the past I made some short videos and posted them to YouTube.

It worked but I was a little unhappy with the quality after their compression system got a hold of it. So I got this idea of posting the video into my own account and then playing it from there. (ya, it was Youtubes fault my videos were bad, sure…..)

Big deal you say, just try to make a video, add a little play button using Actionscript 3.0 and it becomes a big production number.

I like the idea of videos showing bridge concepts because most people (including engineers) have a hard time imagining details from 2d drawings. (Well to be honest, I really just wanted to learn how to make flash videos.)

This video is just under 1Mb and I wanted to see how it played on the web. I’m not sure what the maximum size of flash video I can have on my site before everyone gets bored trying to view it. (Hey it moved, so it must still be loading..)

updated: I just looked at this on the web and all I can tell you is, the cars really move like that in real life……

I am still working on a concept to repair a steel girder bridge that was recently hit. The Alberta Transportation Department has a good introduction to repair techniques.

I am probably going to use a strongback, a beam/deck support used to carry the load while the girder is repaired.

While the strongback holds the load you cut out the damaged portion of the girder. (You will probably need a bunch of temporary falsework to hold up the girders on either side (underneath) of the cut out portion.) Then you place a new T-section and bolt it all together with a zillion bolts. (I suppose this only works in positive moment areas because you can’t replace the top flange without removing the deck.)

It should work but I think it might be fairly expensive to repair four girders and re-route two lanes of traffic.

The Transportation Research Board has put together a list of research topics and they are looking for consultants. I applied for one of the topics. (Hey stay away from my topic!) This is the first time that I have tried to submit a “letter of interest” and I’m not exactly sure what a winning letter looks like.

I like the concept but I wonder how many consultants apply? Not to be too cynical but I sometime feel it depends on who you know with these kinds of things……still I think it is a great idea and hopefully I will get to be involved!