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How to Compare the In-Place Cost of Wire Mesh Versus Synthetic Fibers
June 19, 2012
We know there is a major technical advantage in using synthetic fibers versus wire mesh. The quantifiable evidence shows that the 3-dimensional fiber reinforcement is proactive whereas the single layer of wire mesh, at best, is reactive.
The economic benefits significantly multiply the value of using Fiber Reinforced Concrete.
Here is how to compare the in-place cost of the wire mesh with the in-place cost of both microsynthetic and macrosynthetic fibers.
Wire Mesh Cost
- Material Cost. This is the actual cost of the wire mesh required by code, which includes the overlap. Here the square footage of the project is multiplied by a factor, like 110% to come up with the actual wire mesh required for the project. This factor would include the overlap and waste of the wire mesh.
- The cost to handle the wire mesh on the project (off-load from truck, store, move to point of use). Remember to include the cost of the forklift and operator.
- The cost to place the wire mesh (this cost is in direct labor expenses plus the time lost to place the wire mesh). Remember to include the cost of the forklift and the operator. Typically a four-man crew is required.
- Cost of permanent supports on which to place the wire mesh.
- Cost for the concrete pump to place the concrete (ready-mix trucks are not permitted to drive on the wire mesh)
Wire Mesh a Costly Choice
6×6 W1.4 x W1.4 Wire Mesh Material Cost $0.28/sf Cost of Handling $0.03/sf Cost to Place Wire Mesh $0.10/sf Cost of Permanent Supports $0.030/sf Cost for Concrete Pump @ $750/day $0.075/sf Total Cost In-Place for Wire Mesh $0.51/sf* Factors used in developing the in-place cost for the wire mesh:
- The above costs are estimates and based on a 5” thick concrete slab and a per day placement of 10,000 sq ft. Actual costs will vary based on market conditions and location.
- Labor force to place the wire mesh would include 4 laborers. If union ironworkers are required per the project contract double the cost to place the wire mesh. The cost of one operator and forklift to move the wire mesh from storage to point-of-use was not included.
- The cost of the wire mesh is based on 6×6 W1.4xW1.4, as noted.
- The cost of 6×6 W2.9 x W2.9 in place would be $0.51/sf.
- When costing out a slab-on-ground also include the cost of a concrete pump with the wire mesh in-place cost. When wire mesh is used the ready-mix trucks are not permitted on the base. When fibers are used the ready-mix trucks can pull up on the base and discharge the concrete at the point of use. In this exercise, the up-charge used for the concrete pump and operator is $750/day.
- Remember that the placement time for the wire mesh is increased measurably when permanent supports are required by the engineers.
- This cost does not include lost time required to place the wire mesh nor does it include the cost associated with the required overlap of the wire mesh specified by code.
Further Considerations
If we are conducting a true accounting of cost when wire mesh is used, we must factor in the time used to place the wire mesh twice. Not only is it a cost but it is also may be considered as lost revenue from use of workforce and equipment on another task or project. View the number of days to place the wire mesh as lost days in the construction time schedule.
FRC Cost
Cost of the fibers in the truck is the total cost. There are no additional/extra costs.
- For residential and commercial slabs-on-ground the Total Cost In-Place for Microsynthetic Fiber using the same basic parameters would be $0.13/sf based on a fiber dosage of either 1 or 1.5 pounds per cubic yard.
Fibers a Smart Choice
6×6 W1.4 x W1.4 Microsynthetic Fiber Cost $0.13/sf Cost of Handling $0 Cost to Place Wire Mesh $0 Cost of Permanent Supports $0 Cost for Concrete Pump @ $750/day $0 Total Cost In-Place for Microsynthetic Fiber $0.13/sf* - For industrial, warehouse and roadway slabs-on-ground the Total Cost In-Place for Macrosynthetic Fiber for a similar application would be $0.38/sf based on a fiber dosage of 4.0 lbs/cy.
Fibers a Smart Choice
6×6 W1.4 x W1.4 Macrosynthetic Fiber Cost $0.38/sf Cost of Handling $0 The cost to Place Wire Mesh $0 Cost of Permanent Supports $0 Cost for Concrete Pump @ $750/day $0 Total Cost In-Place for Macrosynthetic Fiber $0.38/sf* Factors used in developing the in-place cost for the wire mesh:
- The above costs are estimates and based on a 5” thick concrete slab and a per day placement of 10,000 sq ft. Actual costs will vary based on market conditions and location.
Prepared by R.C. Zellers, PE/PLS, ABC Polymer, Director, Engineering Services