Formworks and Scaffolds

• Formworks


  Artificial support provided below and around the precast or cast in-situ concrete work
• Scaffoldings


  Arrangement for working plate forms
• Shoring


  Supporting method for unsafe structure
• Underpinning


  Method of strengthening an existing structure's footing
• Temporary supporting structures


  • Formwork
  • Scaffoldings
  • Shoring
  • Underpinning
• Formworks


  • Water-tight
  • Strong
  • Reusable
  • Contact surface should be uniform
  • According to the size of the member
• Types of formwork


  • Steel formwork
  • Wooden formwork
• Steel formwork


  Comprised of steel sheets, angle iron, and tee iron
• Wooden formwork


  Consists of props, planks, battens, ledgers, and sheathing

  
• Concrete construction where formwork is commonly provided

  • Foundations
  • Walls
  • Columns
  • Slabs and beams
  • Stairs
• Maintenance of formwork


  1. For wooden formwork, use cardboard or plastic fiber board. Bolt hole places must also be repaired.

  2. For steel formwork, plates must be leveled by mallet and loose corners must be welded.
• Advantages of steel formwork


  • It can be used for a number of times
  • It is non-absorbent
  • Can produce a smooth finish surface
  • No shrinkage
  • Easy to use
  • Volume is less
  • Stronger than wooden formwork
• Plywood as construction form

  • It is economical in terms of labor cost
  • It is lightweight and handy
  • It has a smooth surface which may not require plastering
  • Less consumption of nails
  • Ease of assembling and disassembling
  • Commonly available

  
• Scaffolding


  Temporary structure constructed to support a safe working platform for men and materials required during building operations
• Staging


  More substantial framework progressively built up as the tall building rises
• Purposes of scaffolds


  • Masonry work of structures such as walls and columns above ground level generally above 1.5 meters
  • Surface finishing such as plastering, painting, and cleaning of a building
• Parts of scaffolds


  • Vertical support
  • Base of vertical support
  • Horizontal member
  • Diagonal braces
  • Block and wedges
  • Nails or bolts
• Removal of formwork


  The removal time will vary with air temperature, humidity and consequent curing rate
• Minimum period before removal of formwork

  • Vertical formwork to columns, walls and beams: 16-24 hours
  • Soffit formwork to slabs: 3 days
  • Soffit formwork to beam: 7 days
  • Props to beams and arches: 7 days for slab spanning up to 4.5 m, 14 days for slab spanning over 4.5 m, 14 days for spanning up to 6m, 21 days for spanning over 6m
  • Props to slab: 7 days
• Formworks for Square and Rectangular Columns

  1. Compute the perimeter of the column

  2. Solve for the total surface area of the lateral faces of the column

  3. Solve for the total area of the columns

  4. Solve for the area of the plywood that will be used

  5. Divide the total area by the area of one plywood to get the number of pieces
• Formworks for Circular Columns

  1. Compute the circumference of a circle

  2. Solve for the area of a circular column

  3. Solve for the total area of the columns

  4. Solve for the number of black metal sheets required

  5. Solve for the number of pieces of vertical ribs

  6. Solve for the number of pieces of circumferential ties
• Formworks for Concrete Beams

  1. Compute the perimeter of the beam

  2. Solve for the total surface area of the three faces of the beam

  3. Solve for the total area of the beams

  4. Solve for the area of the plywood that will be used

  5. Divide the total area by the area of one plywood to get the number of pieces

  6. Multiply the number of phenolic plywood obtained by the multiplier to get the total board foot of the wood frame

  7. Get the number of pieces of wood lumber

  
• The difficulty of how to calculate formwork largely depends on the shape of the concrete form you're supporting
• If formwork can be reused on the same project or on future projects, this will lower the overall cost
• Metal formwork can be reused multiple times, but wooden formwork may not stand up to reuse, especially over long periods
• Estimates of Formworks for a Proposed Two-Storey Residence

  1. Compute the perimeter of the column

  2. Solve for the total surface area of the lateral faces of the column

  3. Solve for the total area of the columns
• Reusing metal formwork


  • Can be reused multiple times
  • Wooden formwork may not stand up to reuse, especially over long periods
• Estimates of Formworks for a Proposed Two-Storey Residence


  • Rectangular Column for Ground Floor = 0.25m x 0.35m x 4.17m
  • Rectangular Column for Second Floor = 0.25m x 0.35m x 3m
  • Number of Columns for Ground Floor = 16
  • Number of Columns for Second Floor = 14
• 1/4" x 4' x 8' Phenolic Board

  6mm x 1.2m x 2.4m
• Solving for the 1/4" x 4' x 8' Plywood Form

  1. Compute the perimeter of the column

  2. Calculate the total surface area of the lateral faces of the column

  3. Solve for the total area of the columns

  4. Solve for the area of the plywood that will be used

  5. Divide the total area by the area of one plywood

  
• Solving for the 2" x 2" Wood Frame

  1. Multiply the number of phenolic plywood obtained by the multiplier from Table 3

  2. Get the number of pieces of wood lumber

  
• Formwork Measurements


  • Mark
  • Quantity
  • Length (m)
  • Width (m)
  • Height (m)
  • Perimeter (m)
  • Area (m^2)
  • Total Area (m^2)
  • Area of Plywood (m^2)
  • Number of Pieces (plywood)
  • Total Board Foot
  • No. of Pieces (Wood Frame)

  
• Number of pieces = 32.43 = 33 pieces of 1/4" x 4' x 8' Phenolic Plywood for Columns

  
• Number of pieces = 244.78 = 245 pieces of 2" x 2" x 12' wood frame /lumber for Columns

  
• Number of pieces = 32.43 = 30 pieces of 1/4" x 4' x 8' Phenolic Plywood for Beams

  
• Number of pieces = 244.78 = 228 pieces of 2" x 2" x 12' wood frame /lumber for Beams

  
• Total Number of Phenolic Board = 63 pieces
• Total Number of Wood Lumber = 473 pieces
• Cost of Phenolic Board = 27,405 pesos
• Cost of Wood Lumber = 70,950 pesos