Thin Shell Concrete Structure: Experiment 01

First try. Fingers crossed.

Enjoy the photo montage of our first experiment.

We used MDF and pine for the structure instead. Also, we used acrylic tube instead of wire nodes.

Finished form work with the members tied together using a zip tie.

Form work after being covered with muslin.

First scoop of concrete on the form work. Very emotional. (´•ω•̥`)

Left to right: Kingsley Castillo, Shelda Kristie (a.k.a ME!), and Gabriel Undery (Fabrication Lab Technician)

First layer done.

A blurry image of concrete sliding down the form work.

Cured first layer.

Applied the second layer of concrete.

Layering the concrete that was sliding down.

Cleaning the structure after being cut.

The highest point of the structure broke.

Separating concrete from fabric.

Split down the middle.

Ready for the Vice Chancellor show.

No reinforcement applied in the structure.

Pillowing detail.

Here’s the link to the original method we were going to follow from our research.

Thin Shell Concrete Structure: Pre-Experiment 01

Instead of that, we used materials that are available in the Fabrication Lab in UNSW that was cheaper. The following will be the materials, methods we actually followed.

Materials

• Quick set concrete
• Muslin
• Zip ties
• Plastic Tubes (16mm diameter)
• Timber
• Chicken wire (5mm grid for reinforcement)

Method

1. Get the Z-axis from the 3D digital model
2. Construct timber frame
3. Put plastic tubing through holes and hold it in place using zip ties
4. Place muslin on top of plastic tubing and secure into place
5. Mix quick set concrete
6. Apply 1 bag of 20kg concrete mix to structure with the wire mesh in between for further reinforcement
7. Glue down the wire mesh using the glue gun (which failed)
8. Apply 2nd bag of 20kg quick set concrete.
9. Once dry, release from the mold

Results from the first experiment.

• Method: We poured the concrete in two batches, this caused the wire mesh not bonding with the first layer. (1st layer: Bastion Quik Set Concrete. 2nd layer: Dingo Hi-Strength Concrete)
• Materials (Fabrics): We used muslin. The big holes made the first layer of concrete to stick to it.
• Materials (Wire): We used 16mm diameter plastic tubes and held together using zip ties. The x and y-axis structure does not intersect properly causing the overall shell structure less pillow shaped.
• Materials (Concrete): The overall prototype weighs 40kg. We used quick set concrete. All the concrete slid down to the lower part and did not form perfect pillows. We used two 20kg bags of quick set and placing it in the sun to quicken the curing, this caused cracks on the second layer of concrete. Since there is a high point in the model, the concrete slid down to the lower area.
• Final Form: The form broke because the concrete was given too little time to fully cure.

Things to do differently:

• Method: Do the two layers one after the other. When the first layer is poured into place, try to push down the wire mesh so it bonds with the concrete. Then apply the second layer on top of it.
• Materials (Fabric): Using a more flexible fabric such as latex might imprint the diagrid structure better. Whether or not the concrete will stick to that, still needs exploring.
• Materials (Wire): Use braided wire and nodes.
• Materials (Concrete): Try using normal concrete not quick set.