The Happy Pontist has another great review of the proposed Calatrava bridge in Calgary. (My hometown)
The bridge is not a typical Calatrava, at first blush I can’t see his hand in the design. When you buy a signature bridge from one of the guiding lights of bridge design, you want a Calatrava.
You want to point and say, “see the tower, the white ribs, definitetly a Calatrava”.
When you get Frank Gehry, you want a oddball, multi-surfaced structure.
Calatrava’s bridge reminds me of a bullet train from Japan or a Christmas candy cane. Its high contrast color does not seem to fit the home of the Calgary Stampede, the World’s largest rodeo. Check out more images of the bridge over at the pontist and let me know what you think of the bridge.
I have just finished up a plan for a new Prairie style 2 span overhead bridge. I started to model my plan in Sketchup, both as a way to learn more about SU and to catch any mistakes in my design.
One of the things I am battling against is how “realistic” to model my bridge in SU. By that I mean, do I include the parabolic roadway grade, which leads to showing camber in the concrete beams, which leads to a varying concrete haunch. (The concrete between the deck and the beams, which helps in adjusting for the camber of the beam.)
Each wing is slightly different because of the 28 degree skew combined with the roadway grade. I don’t think anyone could see the small differences in a “accurate model” vs. a less refined drawing but I would like to see if it is possible to build a model that you could use to verify things like elevations.
I also downloaded a ruby script from here, which allows me to calculate volume quantities from groups or components in my SU model. This helps me check how accurate my concrete quantities. If you want to know more about ruby scripts, drop me a line.
This happens to be post #187 and I thought I would take this time to look back at some posts you may have missed. Afterall, I have some new readers (thanks by the way) who may not have read everything on the blog, I have a ton of work to do and I may have run out of ideas for a moment……
Here is a post about Christen Menn – all around great bridge designer.
On his blog “A place of Sense“, Graeme, wrote a good post about engineers and the sustainable design movement. Architects are way ahead of engineers in developing strategies for going green.
(The whole LEED movement for example. As a side note, I remember a private company starting a business called the “Canadian Standards Association” (CSA). The idea was to get Architects and builders to specify only CSA certified companies for their contracts. So of course we had to pay $50k to get “certified”. But I digress…if anyone wants to start an engineering version of LEEDs, let me know!)
One of the great things about sustainable development is that it recognizes the importance of historic preservation, or retaining existing buildings of any type. You may have heard the expression “The greenest building is one that’s already built.”
Does this relate to bridges as well? For example, we have a concrete arch bridge nearby that was built in the twenties. The city wants a wider cross-section and it does not appear the existing arches can handle the additional load. How do you engineers feel about rehabbing an 80 year old bridge? I’m not taking sides, I am just curious about what would be the best solution regarding existing bridges?
I placed a couple more bridges on my 3D Sketchup Warehouse account here. One is a simple span precast, prestress concrete beam bridge with a spread footing. The other is the model for an ABC bridge I designed with precast deck panels.
How do you teach engineering students? How do they learn? Engineering, like teaching the Law, is built on precedents. Examples are the lifeblood of the system.
For the past 10 plus years I have been teaching, on and off, courses in hydrology, structural analysis and concrete design at the local university. (while working full-time as a bridge designer)
When I get reviews (teaching evaluations) at the end of the semester two things usually show up. One is an appreciation for real life experience (whether my recommendations are good is open to debate..but PE’s in the classrooms is a good thing) and the other is MORE EXAMPLES! Students love examples and examples close to the test questions are even better. But a study by some Ohio researchers found that examples proved a poor way of solving future problems.
Researchers led by Jennifer Kaminski, researcher scientist at Ohio State University’s Center for Cognitive Science, found that college students who learned a mathematical concept with concrete examples couldn’t apply that knowledge to new situations.
This research suggests that examples limit the extension of engineering knowledge to more complex problems. I could not agree more. I see this at work, at school and in my own life. Everywhere I go in engineering, someone asks to see an example before starting a new project. Engineers are reluctant (thats putting it mildly) to try an innovative design without some backup. Examples are the backup, the insurance, if someone else has done a project and it was built, it must work. Whether it was a good solution or not, well, as long as it was built it works! How do you think engineers learn?
I wondered if I could find any bridge engineers on Facebook. Santiago Calatrava is there of course, he has 18,721 fans. Do you think it is a good strategy for your typical engineer or engineering firm to be on Facebook? (I guess it is one way to get your message out…) Calatrava’s site has a number of good images and some short videos of his work.
Just got back from Chicago. I did not get the chance to see any bridges open up but it was fun walking back and forth over them. I read somewhere that Chicago has at least one of every bridge type. I’m not sure about this fact but there are a lot of bridges.
Walked to the Navy pier with my family and saw the fog roll in…..I also saw the hole in the ground for the “Chicago Spire“. It’s in a funny spot by some low rise apartments and behind the Lake Shore highway.
I visited the giant silver “bean” in Millennium park yesterday. (actually its called the Cloud Gate on the AT&T Plaza) It was not what I expected. I thought it would be an overrated sculpture (showing my engineering bias) but it was interesting and the people loved it. One of the things I would like as an engineer is to interact with the public with my designs. Obviously highway bridges may not get me there but what can you do.
It must be a good sculpture if even my pictures look okay….
You probably noticed by now that I spend a look of time looking at projects other than ABC bridges and today is no different.
I saw this video on boingboing.net about a music composer who made a video using Google Sketchup. (I can see this technique being used to promote your bridge design to the public.) Here is a link to an interview with the video director. (sorry about the ads)
I also love the DIY movement and I think this aero-civic design is amazing.There is a lot of engineering behind the $400 in parts.
Its Friday! Ever have one of those weeks….well as the title of the post suggests, odds and ends today.
ABC Posts – If you have some bridge related information or project news you would like to promote, please email me the material at “nielsen at acceleratedbridgeconstruction dot com” (hopefully that fools the spammers but I still seem to get a lot of spam from Russia)
If I link or post to your image and you are unhappy with that, I will remove it at your request. (No one has complained yet, I try to give the proper credit.)
If you have some bridge related questions, I can give them a try. Maybe a Q&A forum, with more knowledgeable readers weighing in?
Bridge picture blog – This is a Japanese blog (I think, I used google translator and that is the one that worked. I believe it is called “tabikappa”(?) and has been showcased on other sites. But it is fun to see the enormous variety of bridges.
I was reading the Happy Pontist’s post about the new Calatrava bridge in Calgary. I grew up in Calgary and my family had a three acre precast concrete manufacturing factory there. I spent my early summers driving trucks, operating cranes, and mixing concrete. (We had an automatic batching facility with underground bins for the materials and a two cubic yard egg beater mixer. It was not fun cleaning inside the mixer, I was always worried someone would turn it on..think pureed teenager)
The Calgary tower (the red bit in the picture) had a restaurant that rotated around. (Movie theaters were located near the base and I remember seeing Star Wars there!)
Our company did all the precast concrete around the new city hall building, which was remodeled for the 1988 Olympics.
Its a favorite trick of politicians to build things under the radar when there is the possibility of negative feedback. Their motivation is easy to understand, what I don’t understand is Calatrava’s reluctance to stand up for his work.
Even if the city objects, I think he should speak out about the merits of his new bridge and go to Calgary for the grand opening. What is the point of building a bridge of this magnitude without some fanfare? I think if Calatrava spent some time in Calgary, making the rounds, he could address concerns and build support for the bridge. I wonder how other engineers handle this situation. Do they try to address concerns or do they take the money and hide? Maybe in this case its too late but I think he should have tried.
I downloaded a new cad program called DoubleCad this morning and I am trying it out. I typically use Bentley’s Microstation cad system but I wanted a low cost (free is best!) cad program I could use on my laptop. DoubleCad has a free version of their software that SEEMS unaffected by spyware, nagware or any other ware. It mimics autocad LT or so they say. I’m not really sure because I have not used autocad lite.
If you have some good/bad experiences with DoubleCad let me know. So far it seems interesting.
Other open source software I use/recommend.
Google sketchup – best 3D drawing software and FREE! Every engineer should learn this software.
Openoffice – good open source (free) excel-like, word-like, powerpoint-like software.
Posted my summer grades this morning, summer officially begins…
I had a meeting yesterday about a little ABC project I designed. One of the new things we are trying for this bridge is a reduced construction period. In the past, our ABC projects would get the typical construction timeframe that you would receive for a standard cast-in-place bridge (about three months).
This made it difficult (to say the least) to determine how many actual days the project took to build and whether or not that achieved the ABC goals. A contractor could work a few days on the ABC project, rotate out to another project and come back a month later and finish the ABC bridge. This is not unusual, just think of how many times you saw a construction project blocking traffic and you wonder where all the workers are….
When my family manufactured precast concrete products it was often feast or famine. So we had to jump from project to project to keep everybody happy (mostly those that screamed the loudest). I can’t remember how many times we were threatened by a job superintendent. (Man, that is a rotten job)
For this latest project, we gave ten days for construction, with the incentive of a $5000/day bonus (up to a maximum of $25,000) for every day under the ten. (Meaning, install in five days, make 5 X $5000 = $25,000)
Since the timeframe is so tight everything has to work and I plan to be on site to make quick decisions if the need arises. I will post more pictures about the projects as they become available.
Update #1: The original contract cost for the bridge was just over $200,000, so $25,000 is a good incentive.
One of the things you see often in bridge design is gingerbreading (GB). Essentially, adding ornamentation to a structure. (Image is from an actual gingerbread bridge competition.)
You see it a great deal of this in modern highway and pedestrian bridges. It is usually cheaper to add elements like towers, sculptures, flower boxes, paint, you name it, instead of altering the structural members.
This makes sense because 95% of bridges are pretty basic structures. (Okay I made the number up but its a lot trust me.)
Signature bridges are beautiful but they are really not the norm. A bridge designer is much more likely to work on a typical highway bridge than a Calatrava original. This goes for architects as well. Most aesthetic enhancements will come in the form of gingerbread. The challenge is to make the gingerbread appropriate for the structure. (Don’t get me wrong I would rather build an arch bridge than a bridge with GB. A “pure” structure is usually the best but you have to be realistic.)
Good details like the ornamentation of the Congress Drive bridge in Chicago adds to the structures overall appearance but it is not necessary for the structural integrity of the bridge.
(Image – Michigan Avenue Bridge. I am going to Chicago in a week and I can’t wait!)
This to me is good gingerbreading. Bad gingerbread is when you try to hide the structural elements with facades.
This structure, utilizes typical precast interior girders with variable depth spliced exterior girders. It looks like an arch but it is not. It is attractive but it is not really showing you have the elements carry the loads.
As designers know, connections are typically difficult to design and have the most risk of failure. (I remember in engineering school being told most structures fail at the joints. Then I was told we would not be studying connections until grad school.)
Connected prefabricated elements are even more problematic because unlike cast-in-place structures they never attain a fully “integrated” connection. A couple of the connections I came up with have been included in the manual.
(Of course, my name was not included as the developer. Bitter! Oh not me…)
Updated: The title for this is a little off..and so is the post. But in my defense I have to make a final exam this week and I have to turn in three bridge projects on Monday…..
Engineering standards were developed to speed the design process and, hopefully, reduce the cost of bridges through the use of repetitive details. Think Henry Ford and model T’s. This is the positive side of standards and for most bridges, standards are a good thing. You spend so much time and energy developing the standards you don’t want them to go to waste. So you protect and implement them every chance you get.
But standards can also breed complacency, stifle innovation and stunt the growth of an engineer’s skills. (Imagine all you see everyday is someone else’s design.) Without challenges, its hard to become a better designer.
Students typically learn engineering from following examples.
I have found from my teaching that it is difficult to develop new examples because I am always worried I did something wrong. (This is too related to standards, just wait.) It is actually easier just to pick an example from another concrete design textbook.
Standards are like that. (See, I told you to wait) They have been checked and rechecked. They provide for the most part, an error free design, one you know works. But without gaining new skills through challenging designs how can you ever learn enough to design a non-standard bridge?
Check out the webcam for the new Center Street Bridge here. (The one where the guy saved the woman who went over the low head dam.)
Google makes it easy to upload and share your components and models. I find (when I have the time) that it is a great exercise to draw up your bridge before finishing your design plans. Since Sketchup models can be drawn to scale, I often (often, should I admit that!) find little errors that I can adjust in my plans. It is difficult to draw a 3D bridge exactly to scale because of things like beam camber and haunches but you can get pretty close.
Just go to Google’s 3D warehouse and search for acceleratedbridgeconstruction. Not much there yet but I am working on it.
I don’t have much to post about today. The Happy Pontist has a good post about modified design charrettes. I have experienced a couple of charrettes, essentially a group think about design ideas. The good and bad of the process is all ideas are considered equal. Not every idea is possible.
One of the ways engineers are lagging behind is in the area of leadership. By that I mean when engineers are managing a project they try to combine the requirements of the other participants into the structure. This often leads to a safe but boring final bridge. (most engineers would argue boring is a good thing.) We tend to take the requirements of other engineers seriously and bend the project to achieve their goals as well as our own. You say you need a round column because it is easy to pour, you got it. What, curved girders are tough, no problem we will just use a series of straight beams instead.
Architects have a different approach, they envision a concept and the engineering has to accommodate their vision. I think engineers love the challenge of designing the structural aspects of someone else’s idea of nirvana but when it is their turn to lead the charge, compromises will happen.
So why is this a bad thing? Engineers are listening and trying to build an easy, cost effective structure. My problem with this approach is sometimes the goal is to build something that should not have compromises. Once an engineer is tasked with designing a signature structure, it goes against their nature to say “nope I will not compromise, make it work” to other engineers.
How many times have you heard an engineer say ” I don’t care what it costs, I want it to look this way”.