COEN Pre Cast panels in Moolap was kind enough to let us have a look around their factory and take a few photos of the casting process. After shop drawing production and the consultation, a final panel design is decided upon. It is now time to begin the casting. A casting bed is prepared, by washing, as you can see in the picture to the left. This removes any aggregate or dust from previous casts.
Next, The cast is boxed up, using LVL beams as formwork. Over longer spans, LVLs are preferred as there are less defects in an LVL beam than in a regular piece of timber. The LVL's are purchased in packs and are often reu-sed many times. In the case of the cast we were looking at, 100 panels were to be produced to the same specifications, therefore the LVLs were to be re-used 100 times.
After the formwork, reinforcement is put in place. In this case the Reinforcement was F102 fabric. This is reasonably standard in these panels. The reinforcement sat on bar chairs 75 mm high. This meant they were right in the centre of the 150mm panel, providing it even with stress support throughout. There is only one more detail to add before pouring.
This detail is the panel's lifting point. This shows the back of the point which will be cast into the panel. Note the extra bars of reinforcement around the point. This lifting point is capable of supporting 9tonnes of concrete panel. This panel weighs 10 tonnes, so the lifting is carried out using 2 points. This distributes the load. Extra bars of reinforcement are attached to the mesh using tie wire. Ensuring the correct assembly of the lifting points is perhaps the most crucial part of the casting process and is often overseen by the factory's manager or structural engineer.
left is a picture of the end of one of the panels, note the threaded dowells and also the lifting points. Once the panels reach practical completion, they are placed in racks, as seen in the following photo. Once in these racks, the panels are allowed 24 hours curing time before they are suitable for construction. The site surveyor from the project will come out to the factory and inspect the panels, with regards to lifting points, reinforcement, and general size and colour before approving them to be transported to site. My next blog entry will include transport details.
