Salli Hanninen Arch-1392: Progress

To do:

Research formwork for concrete model
Start modelling formwork backup

For the concrete model I was asked to research and model the formwork as a backup if the complex formwork did not export to Sketchup properly. As I have worked on site before I am familiar with formwork for slabs and beams but I have not witnessed a complete two storey building being Cast in place with concrete. I know one issue with formwork on large structures is that the concrete needs to be vibrated so all air is pushed out and concrete reaches all areas of the formed structure. This 2 storey building will need to be constructed in stages.

- Formwork design must comply with AS 3610 Formwork for concrete

RESEARCH

image01: meeting with concreter to discuss how you would go about forming the 2 storey house. The formwork consists of plywood sheeting fixed with horizontal and vertical timbers (4x3) as well as bracing on both sides of the structure.

image02: this is my initial drawing trying to clarify formwork infomation. I have drawn the plywood horizontally but needs to be vertical. Rod holes that are a feature on exposed concrete walls are only used for supporting formwork rods to strengthen formwork, nothing to do with structural elements of the concrete. (see image03-06)

1. Plywood

2. Bottom sill plate (4x3 100x50)

3.Verticals

4. Bearers

image03: I took this shot at UNSW, at the new housing. They had nice finishes on the concrete and there was minimal air bubbles in the concrete

image04: The rod holes have been finished with cement for a clean finish as this wall is on clear display.

image05: This is in a carpark in Bondi Junction, the works are not as clean as the UNSW housing works. The plastic is still left in the holes but this is a carpark and details/ finishes do not have to be exact.

image06: This image was to show rough rod spacings.

image07: a standard plywood sheet is 1200x 1800/2400. The bottom bearer needs to span along the entire wall (continuous). If a bearer stops at the plywood end there needs to be a double bearer fixed so there is stregth in the overlap. The bottom bearer is either a 4x3 or 4x2, all timber is fixed by concrete nails through a ramset gun. The following horizontal timbers are set at 300,400,600,600 etc. The vertical timbers are spread roughly at 4 by 1200, they are always place on ends.

image08: all plumbing, electrical, openings, windows need to be planned and complete before both sides of the walls is erected.

image09: I was very unsure how to form around a window but the concreters explained that the plywood will go completely past the window and on the inside will be a structure of plywood and timbers to ensure no concrete goes into the opening. The opening is strengthen with 100x50 timbers.

image10: i was also unsure how the formwork gets constructed near the skillion roof, whether it is staggered or flush at a angle. There is a major issue pouring concrete around the windows (highlighted) the concrete needs to be extensively vibrated to ensure all air bubbles are out. The house will need to be poured in two stages.

BIM MODELLING

image11: I have modelled one board with a bottom bearer and vertical timbers.

image12: The horizontal timbers are placed at the estimated spacings 300,400,600.

image13: I modelled the reinforcing mesh in which does not go through the window openings. I have also modelled the window plywood structure without the timber bracings.

image14: One side of formwork is erected, then the reinforcing then the other side of formwork is fixed and supported.

image15: The levels in which i have modelled the plywood up to. The first pour of concrete will be the ground floor. This will have to cure up to 7 days.