Updated March 17th, 2019
|Slab Form work|
“Professionally built form work is must for producing quality concrete.”
Many different methods are used to make form work for slab. It depends upon type of shutter material used for making concrete form. Such as you can use only “wood and bamboo” or only “steel shutter material” or combination of wood and steel shutter material for making concrete form work for slab. So, the making method of concrete form will differ for different shutter material. Here I am sharing a technique for making concrete form work using only “steel shutter material”.
Form work for slab starts after finishing column casting. Column casting is done up to beam bottom level. However, everything is ok, required shuttering material is arranged and workers are ready. Now start making form work for slab.
Read More: Preparation for Constructing RCC Slab
Step by step procedure of making form work for slab using only steel shutter materials:
Step 1: First Take the desired slab level and mark it on column reinforcement. Practically level is taken before column casting. So start with that.
step 2: Fix the beam bottom between columns. Weld the beam bottom with column reinforcement. Give support to beam bottom with steel props. Spacing of props should not exceed 2.5 feet depending on beam span. Weld props with beam bottom to keep the props in place.
Step 3: Now fix the inner part of beam side with beam bottom by shutter clip or nut-bolt. Make sure foam is provided into shutter joint to make the formwork leakage proof.
Step 4: Put scaffolding on base plate. Spacing of scaffolding should be maximum 4 feet. Fix cross-bar with scaffolding to keep it in place.
Step 5: Use joint pin to put one scaffolding above another.
Step 6: Put U-head on the top of each scaffolding.
Step 7: Now start laying 4″x4″ MS hollow box on U-head. Spacing of runner should not be more than 4 feet center-to-center. At this stage level the hollow boxes by adjusting U-head in accordance with marked slab level.
Step 8: After all big runner are leveled then start laying small runner (1.5” x 1.5” ms hollow box) perpendicularly on big runner. The center-to-center distance of small runner should not exceed 1 feet.
Step 9: Check the slab level all around again with water level.
Step 10: Now start laying plain sheet on top. Lapping between plain sheets should be minimum 2 inches. Keep in mind that If you place plain sheet parallel with small runner then keep every sheet joints directly on small runner.
Step 11: Now make the sheet joint water proof with masking tape.
Step 12: Apply oil to all shutter faces which will contact with concrete to avoid sticking concrete with form. You can use any shutter oil for this purpose. But I found 1:10 Mobil-diesel mix is better.
In this article I used only steel Shuttering material for making this slab form. It requires more skilled worker. Later I will write the procedure of making slab form using combination of wooden and steel shutter materials. So subscribe to RSS feed to get update.
Did I miss anything? Please let me know through comment.