tallbridgeguy

Yes I have read about the wobble of the bridge when it first opened but i never saw this video. ( I realize it is old news but it is still interesting.)

My last post showed a bridge concept over what I thought was a river but was instead a railroad system. (Seems fairly obvious in retrospect, thanks HP) But I still thought the trees lent a natural component to the bridge, which reduces all that harsh concrete. As an engineer I would hate vegetation on a bridge but as a pedestrian I think it would be very enjoyable.

Urban bridge gardens would be fun but I can see the problems. Leaves, brush, weight, water, missiles for kids, and a variety of other problems. I have seen some bridges with small planter systems but never any trees. Has anyone seen a bridge with trees on it? (Send the link!) I doubt any engineer has designed one but I would love to try!

Update: HP pointed out this bridge with trees.

www.foxysislandwalks.co.uk

I followed the link on the Happy Pontist to this bridge by cepzed designs in the Netherlands. The bridge will be built in Utrect, the fourth largest city in the Netherlands. (Hey I can google)The bridge has great access to the river(?) through openings in the bridge. (Although the image does not show the railing required to stop pedestrians from falling into the holes, yikes) It also looks like it could be built at a reasonable cost.

I think it is a very appealing design but the first thing that came to my mind was, how will you drain the water from the trees? Also how will a growing tree change liveloads as it grows? So, the first I think of, is the challenges of determining the loads, the span arrangements, and the construction sequence. I must be an engineer.

Take a look at the design and think about what comes to your mind. Me, I am going to go look for more bridges with plants on them.

cepezed designs rabo bridge

Friday roundup (or the lazy man’s blog post.)

The happy pontist has a number of good posts on tensegrity bridges. I never knew they existed but I am not a fan. I can’t stand pointy things and while it is interesting, the chaotic appearance hurts my head.(I’m not worthy)

Also from a HP is a great link to the deputy dog website and TRIDGES!  I want to design one! deputy dog also has some great pictures of a round bridge.

And my all time favorite. The bridge of death.

Can you get enough vintage pictures on a Tuesday? Check out the photolibrarian’s collection here. (Don’t worry there are a few bridge pictures in there, so it is related…..)

So if your a bridge designer you have probably faced one of these scenarios.

1. You prepare design cost estimates for alternative bridge designs. Maybe one concept is a concrete bridge and the other is a steel bridge. The client picks the lower cost alternative. Late in the design, costs are reevaluated and the chosen concept comes in higher than previously thought. Not just higher but really higher, maybe twice what you originally calculated. Now you are late in design and the client is wondering if the wrong bridge type was chosen. Do you continue and justify the design saying “well both alternatives would have doubled in price, so no problem”. Or do you redesign? ( A dreaded word in engineering.)
2. A city wants a new signature bridge. A budget is set and a design competition is held. The winning design is guaranteed to fit in the budget. The engineering firm gets heavily into design and determines the bridge budget has increase by 50%. But the bridge has been scheduled to let next year and a redesign is not possible.

You see this all the time in engineering. The initial budget always seems to go up. Engineers require a fully fleshed out concept to determine the loads and the final structural element sizes. It is very difficult to redesign because that often means starting with a brand new model to develop the loads. Even a small change may slow do the final design.

One of the solutions is to spend some time evaluating concepts before starting. You would think this is an easy answer but it requires an engineer with a great deal of experience.

Most owners don’t want to hear that their new bridge will double in cost. Some designers are happy to go along with the low cost estimates because they know that a redesign will not be possible late in the game and the owner will find the money. Other times a good concept was just let at the wrong time.

The Architectural Record is a great website covering all thing Architectural. If you search their site using the word “bridge” you get quite a few interesting projects.

Another site has a good article on Architectural criticism. Eikongraphia. Seems they are having the same questions about how to critique a structure as we are..but I have to disagree with the comment about having a neutral viewpoint. A well reasoned point of view adds a great deal to the understanding of a project. You can’t disparage a structure without also explaining what would make it better.

Also:

I don’t know exactly why but I love this site, http://architecture.myninjaplease.com/ .

Best quote:

• Q. Architects are ninjas?
  A. Not all of them – but most, yes. Think about the similarities: both have underground extensive training in multiple defensive and offensive arts, neither sleep [its the cousin of death], both know everything about everything – and are constantly schooling the masses, both exist best in total harmony with their environment, both [well, most] operate in the background – manipulating the world around them without the knowledge of the masses.

Cool graphic: (check out what it means on the site:)

This is probably common knowledge but Google is sponsoring a bridge competition for their Sketchup software. Sketchup is a marvel. A free 3D drawing program that is easier and more effective than any other 3D software I have seen. You can draw your design quickly and to scale.

If your a student, get it, and use it.

It has been awhile since I have found an accelerated bridge construction project to blog. Michigan had a bridge conference and I found two presentations.

Both presentations are here. 2009 Michigan Bridge Conference.

One of the presentation covers the Parkview Avenue bridge over US 131. A 249 foot, 4 span all precast bridge. The cost came in at $2.84 million, with a build time of 2 1/2 months instead of the typical seven months. They used webcams to view the project and precast round pier columns. It is worth downloading the powerpoint and video. (Note: the file is zipped and around 64 MB)

The other presentation covers a pre-fabricated bridge. It shows the Texas prefabricated barrier system. (Smaller file download)

Located in Amsterdam, The Netherlands.

An old article about architects taking over pedestrian bridge design.

The Esplanade Riel Pedestrian Bridge in Canada. Featuring a restaurant.

Credit: Chris Garrett

The stainless steel Temple Quay bridge in Bristol.

credit: pricetags.wordpress.com