Building Construction formwork design

Form Work.

Inspection item at the site

The following items were checked before the concreting.

(a)                Marking

(b)               Level of bottom form

(c)                Alignment in both directions

(d)               Spacing of support, shoring and joists

(e)                Sectional Dimension

(f)                Required Embedded material

(g)               Gaps in between form work

Form work for column

Normally coated fly wood from grease mixed kerosene were used at the site.

It was necessary to consider available size of plywood board, before decided the way of fixing. Normally available size of the plywood board of this site was 1220*2440 mm. If the column size 600*600 mm, it was necessary to use the proper method for fixing of form work to minimize the wastage of materials. If the concrete height was more than about 2400mm, then fixing of the form work was shown bellow.

One side of the column =600 mm

As plywood size 1220 then fixing of plywood as above figure, plywood could be used directly without cut-off. (1220-100-12*2=1096 mm). Other side of the column equal to 600 mm then plywood could be used two columns by cutting two parts as shown above figure.

Form ties (separators) were used to maintain the spacing.

Method of fixing form work for column

Step 1: Kicker was fixed around the column marking and sponge was also used for avoiding the leakage of grout during concreting.

Step 2: Boards were prepared as above figure, before fixing of board to kicker.

Step 3: Separators (form tie) were fixed as above figure to tie the plywood board. (Separators are fixed in this all four side.

When the separators were fixed, it was necessary to determine the height of the column and width of the column. Normally, vertical distances between the separators were increased from bottom to top. Practical experience decided distance or calculation.

Step 4: galvanized iron Pipes were fixed as shown above figure. (50mm diameter steel pipes)

Method of checking form work and column before and after concerting

Step 1: Before concreting the column, it was necessary to check the dimension of the column and straightness by plumb bob. (By checking top and bottom of the column, it can be ensure throughout the column has same dimension)

Step 2: After concreting of the column, it was necessary to check the column as above mention. Figure of the checking method was shown below.

Besides these checks, hamlet is used to ensure the proper compaction of the concrete during concreting by striking the column form work.

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