Wednesday, January 07, 2009

Concrete Trolls (not Trowels)

My friend Sandy posted this photo of the Fremont Bridge troll in Seattle on flickr a long while back, and I really enjoyed how LARGE a sculpture it is. Please note the VW gripped in its left hand should you think that the person sitting on said hand might be just a tiny doll.

Jump forward a few years, and I am at work flipping through some very old Landscape Architecture magazines at work when I come across a short article and some photos describing the construction of the troll. I misplaced my copy of the article, but I have these pictures to share with you. I apologize for the lack of photo credit, but that's missing with the copied article.

The base form of the troll was wire mesh that the artist then covered with layers of shotcrete, with hand-trowelled layers added later. If you've not seen shotcrete in action, it's like if a powerwasher was spitting out a thin concrete mix instead of high pressure water. Gunite is the same type of thing, with shotcrete being the umbrella name for such processes. Typically, shotcrete is, as I said, a very thin mix with a fine mortar-like aggregate and a high percentage of cement compared to sand. So, you still have the three main concrete ingredients: cement, aggregate and sand.

I was looking for more good examples of shotcrete use, and it's definitely more of an industrial product than an artistic one. Swimming pools, skate parks, erosion control, and hobbit-hole wine cellars seem to be some of the more popular uses. The skate parks produce some of the more interesting examples of shotcrete use, in my opinion. Here's a cool one in Reedsport, OR designed and built by Airspeed Skateparks.

In my search for interesting shotcrete images, I stumbled upon ferrocement, which is shotcrete's close cousin. Unlike shotcrete which has all three usual component of concrete, ferrocement doesn't have any aggregate. It's just cement and sand on a wire mesh. It's also not shot out through a high pressure nozzel. Instead, it's typically hand-troweled onto the mesh surface. So, it's a lot more labor intensive process to create a ferrocement structure or sculpture, but the results can be very cool. A lot of Gaudi's organic architecture, for example, is based on ferrocement. In places with cheap labor, it also seems to pop-up as a popular construction technique. Here are some shots I found of projects in India and Mexico over on the website:

All of this has me wanting to come up with new ways to use concrete and cement in future landscape architecture projects. I challenge you to do the same as we kick off 2009!

1 comment:

Mikelfa said...

I'm doing a documentary on the making of the Fremont Troll. Any chance of using some of the images of the troll being built in the doc? You'd be credited, of course. Thanks. A link to a trailer for the documentary can be found here (password, if needed, is Troll):