tallbridgeguy

The concept for the New Dodder bridge, made this list (# 46) of futuristic design concepts from Webdesigner Depot. Pretty cool 3-D renderings.

Dodder Bridge

I was having a conservation with a colleague today about whether or not an engineer is able to design a signature bridge.  By design I mean, develop the artistic concept, or look, of the bridge.

Santiago Calatrava is an Architect first, with a dash of engineering thrown in. (I know he has an engineering degree but he doesn’t seem to know it, looking at his designs.)

Photography Artist Linda Walldez

Engineers are always developing rules for bridge design, for example, it should be true to it’s function. (meaning its a bridge, so act like one)   But Architects don’t play by those rules. They know what a client really wants is something special, something unique, not a bridge with a side of Art, but a story.

The Happy Pontist ( HP, a very good writer) does a great job of discussing the state of bridge criticism concerning engineers and bridge design. I agree completely with him/her (I don’t know) that engineers need to get in the game and start talking about good and bad bridge design. We should be free to dislike a bridge and let everyone know it.

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Well, I was just reading the new report about additional educational requirements to become a professional engineer, put forward by the National Council of Examiners for Engineering and Surveying. (NCEES report)

Essentially if you want to be a licensed engineer by 2020 (and who wouldn’t) you have to have a masters degree in engineering and a number of years of experience. (The number of years varies in the chart, in the paper, but it looks to be a minimum of 3 years)

The first part of the paper deals with how Universities are going to deal with the influx of new students seeking to gain their masters degrees. (It seems odd that the first thing NCEES worries about is the burden on Universities and not the poor students who have to fit the new requirements into their already busy lives.)

I liked this sample question:

Will bachelor’s-degree recipients with low grade point averages (GPA) have a problem
becoming licensed because their GPAs prevent them from being admitted to a master’s
program?

Will they? How about this quote.

In the Economic Impact section, the task force considered it likely that the value of lifelong earnings would offset the cost for pursuing the proposed additional education requirements.

Since I already have the masters degree and the P.E., I am off the hook but if your a student or a parent of a future engineer, be aware of the coming requirements. Good or bad they are coming.

When I was looking into what could be done to improve the “look” of standard precast beam bridges already in service, I investigated the use of staining systems. Simply put, I looked at painting bridges.

Since bridges are huge and subject to weather extremes, it is essential to properly prepare the concrete surface and pick the right staining system. We used a Sherwin Williams Acrylic stain.

I tested the system on a nearby bridge over 8 years ago. It still looks great.

Unfortunately, I was only allowed to use a couple of basic colors which closely resembled the local Walmart store colors.

Now everybody calls my bridge the “Walmart Bridge”.

Still the bridge looks good (open to debate of course) and the paint system passed with flying colors.

The difference between paint and bare concrete is easy to discern.

So my county bridge design (see earlier posts) was finally let. The low bid appears to be just over $200,000 dollars. For a 50′ x 28′ bridge that works out to about $142 /sq. ft.

A county would have put in a high abutment bridge (then they could use non-prestressed deck panels) instead of my 50′ span. Their typical cost would be around $125 / sq. ft. (about $140,000 for a 40′ x 28′)

I think my bridge will find a market, especially if it can be installed in 5 days! But further design is required to get the bridge down to a competitive price.

I don’t know much about the webmaster of bridgehunter.com but it is full of old and historic bridges. Currently, it holds over 31,000 bridge records, gathered by a number of “bridgehunters”. The Iowa Dot also has a good website dedicated to historic bridges found throughout the state. Historic bridges of Iowa.

Scour is not a great sounding word. In bridge slang, scour means “water move soil”, seriously, look it up. (Hey I have not had much sleep since giving the exam last night and then getting up at 5:00)

Anyway, scour is one of the reasons we use pile foundations around our river systems. Essentially, high water flows removes the soil around our bridge foundations. If the exposed length of piling is too great you may experience some buckling of the piles. If you used a spread footing, the water flow may undermine and damage your bridge.

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I’m giving the third test to my concrete design class. It is all about shear design and development lengths tonight. I have 103 students in four rooms working without air conditioning. So…here is a picture I made of our three dogs to get you to the next post.

Christian Menn born in 1927, is one of the great outspoken bridge designers of our time. He has worked on such bridges as the Leonard P. Zakim Bunker Hill Bridge, in Boston and the Sunniberg Bridge.

Here is a short interview he did for a swiss web journal and a link to his website, where he has beautiful pictures of his bridge designs.

Last week I went out looked at some bridges that required repairs to stay in service.

I saw this one lane truss bridge over the soldier river. It was posted for 11 tons and featured a wood plank deck.

A new crossing was being built slightly upstream, so I doubt this bridge will be around for long.

A problem on some of the bridges I looked at was the issue of strands breaking out of the ends of the beams. Fixing this will take a little thought.

One more photo of the truss bridge below the fold.

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