Monthly Archives: August 2009

Oblique Strategies cards

Well I had never heard of these cards until HP pointed them out to me. The cards, originally started by Brian Eno (yea Roxy music) and Peter Schmidt, are intended to jump start your creativity.

The Oblique Strategies cards “serve as a series of prompts which said, “Don’t forget that you could adopt *this* attitude,” or “Don’t forget you could adopt *that* attitude.”

Essentially they are questions to help loosen up your design approach in the face of heavy time constraints. Three sets of questions are online.

Some of the questions I liked are:

Abandon normal instruments

Define an area as ‘safe’ and use it as an anchor

Do nothing for as long as possible (my personal fav.)

Do we need holes?

Take away the elements in order of apparent non-importance

Computer rendering

The images below were drawn and computer rendered by a friend of mine. (The arch will be built in the next few years.)

He did not develop the design but provided the final images for public viewing. i believe he spent well over a 100 hours drawing up the single span arch.

When you enter a design contest, is this the level of realism you require or is it better to leave the concept a little more vague?

Design thoughts or why architects are crazy

I have been trying to use the creative side of my brain lately and I am finding it is woefully underdeveloped. To try and jumpstart my inner Calatrava I spoke with an architect friend of mine about design ideas. I always thought it was important to design a bridge that reflects some of the context the bridge will be embracing. For example, if a city was famous for tall building maybe a tall bridge would be the way to go. (Or a short bridge to play off the height of the surrounding site.)

But then my friend springs the idea that a design can just be cool and it can be left to others to define what the bridge means. The idea is, you can design a bridge that can be placed almost anywhere. You could have a bunch of innovative designs sitting on the shelf just wanting for a design competition.

So now i am confused (not the first time.) does a bridge have to mean anything to a site of just look cool?

Some random bridge pictures for a Saturday morning.

Stressed Ribbon Bridge

So I finally picked a direction after much head scratching for the Calgary bridge. I had an idea that used a stressed ribbon bridge. BUT…when I started laying out some ideas in Sketchup I didn’t like the idea of having a sag curve over the water. It seems to require fairly tall anchorages which I think are a little bit of overkill for this site. Which means going back to an idea I had using a cable stay kind of structure. I think the cable stay will allow a positive profile grade which looks cool and helps to drain the water to the end supports. So back to the drawing board.

The biggest problem (among many) in entering a contest by yourself is the amount of work involved. I need interns, preferably professional engineers, architects, graphic designers who all work for free. Then I could sketch ideas and the interns could work fleshing them out. “Hey you, another coffee latte over here, stat”.

An example of a stressed ribbon by Brego on wiki. (It kinda looks limp to me.)

Great White North Bridge

I lived in Calgary for 25 years and the thing I remember the most is playing road hockey night after night with my brothers.  We used tennis balls instead of a puck and we had to rotate them when they eventually froze. (Playing goalie and getting hit with a frozen sphere can hurt…you know where.)

I have been trying to come up with a design for their new St. Patrick Island link but I am having bridge designer’s block. Reading the RFP yet again it seems the money is on one bridge with some kind of access ramp from the bridge to the island. If I have my math correct (remember I use feet now and not meters..) the bridge will float over the Island about 3-4 meters, to stay above high water levels. The recommended orientation is shown in red below. (not my design just a marker)

My design block is trying to figure a decent ramp down from the bridge. I thought maybe a nice 10-20m diameter meeting plaza, over the Island, would provide a nice spot for people to sit, eat lunch and meet up. (wow that’s original) The plaza would have a ramp the would connect down to the island. I thought about a spiral ramp underneath or using a great staircase with an adjacent ramp. (maybe the staircase could then be used as amphitheater seating for a performance circle at the end of the ramp.)

Then I thought isn’t that overkill for this spot? I also hate the bridge flying over the Island. Without a good design, the area underneath will be a dead zone. The Island may not have much of a beach but a bridge overhead can’t be that appealing. Then I thought the best solution would be two smaller more intimate bridges with a path between them and some great park landscaping all around. (If the landscaping was flooded the cost to fix it would be small.)

The purple bridges in the picture represent the smaller bridges. (The white bridge is an existing suspension bridge.)

So am I off my rocker to think that the massive bridge is a little much for this site? Can the bridge floating over the Island be designed to avoid the dead zone underneath. ( I even thought of putting shops under the bridge in a circle, but I worried they would be flooded out.) Help!

I have added some site views below the fold.

Continue reading

Calgary Bridge post 5? (lost count)

If you saw the link in the previous post to the latest FAQ from the Calgary Municipal Land Corporation, you might have read some odd things.

For me, two answers stood out. 1) The RFP and the FAQ both give the impression that a team is the preferred option. Since I am a team of one, this might be a spot of trouble for me (yes its all about me)…

Answer #2) The CMLC is the sole judge in step one and they will filter which designs move forward to the public. This seems fairly odd for a “open” design competition, because the CMLC’s criteria for moving options forward is unclear. The first batch of entrants could hold a great design but only the ones the CMLC allows through will be moved into the public sphere.

I like the idea of throwing all the entries into the open. Let the public decide what the best bridge design is for the residents of Calgary.

If you don’t make it through the first round, send me your design I would love to post it.

I also wonder if posting your design and entering the contest would help you move to the second round? What I mean by that is, would it be possible to build enthusiasm for your design if you advertised it before submitting it? Imagine if Calatrava posted a solution a day before the final turn-in. I wonder if that would help or hurt a designers chances? Has anyone done this and won?

Continue reading

Some bridge odds and ends.

Proposed skylink bridge. Not sure how the plants work. (sketchup drawing.)

Image: Gotta admit it looks cool. But will it happen? Courtesy of Lukmire and Associates.

Proposed pedestrian bridge in British Columbia, Canada. I’m not sure the structure would actually stand up with those member sizes and cable placements.

Architect Gregory Henriquez's proposal for a pedestrian bridge across False Creek that would connect Kitsilano with the West End.

These are bridge pictures I stole from the Happy Pontist. I think these concepts would work for the Calgary bridge. (sorry I tried to stay away from that bridge!) (Below the fold.)

Update: Here are some answers to recent questions about the Calgary bridge. Mine was #16.

Continue reading

Calgary site

Sorry about the Calgary bridge appearing so much…I will try to get back more regular programing..(quick photomontage practice)

Calgary Bridge post 4

I was looking through the competition “rules” for the proposed Calgary pedestrian bridge and a couple of things stood out. The budget is $25 million which includes all design fees, permits, construction, etc to get the bridge in place. So when I get my 10% design fee (Ha!) the bridge will have to be built for $22.5 million. (They did hint they could go higher with the budget if the bridge concept was worth it.)

In my initial planning I thought two bridges would be the best way to go. With that in mind I looked at the distances and I calculated one bridge with a 110 m span and one with 68 meters. (Not the same as I showed in an earlier post.) I thought some curved structures with one or two piers in the river would make the bridge fun to walk across. (Straight is boring)

BUT the RFP suggests that piers in the river would be frowned upon. That may still allow two bridges but it forces you to look at bridge types that can handle a 110 meter single span. Most likely (I think) concepts will show a single tower (or sculpture) on the island, used as a cable stay bridge. (Like the goofy Golden Trumpet I made this afternoon for fun. It has yellow a brick road!)

The island is the low spot at an elevation of 1039.25 m. The minimum elevation over the highest ice level, with 1.5 meters of freeboard, is about 1043.5 meters. The two banks are at about 1043 meters in elevation.

Hey HP if your not in the competition, do you think the lack of piers in the river limit the designs?

One with people!

Quick bridge render

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…

Calgary Bridge part 3

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)

New Calgary Pedestrian Bridge Competition

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.

Design Experience

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?

Franken-girder

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..)