All Formstress Double Tees are cast from 45 MPa (at 28 days) concrete.
When specifying your double-tee units, your project structural engineer should provide the estimated depths based on the tables above and the floor loads. When Formstress are taken on our engineers will fully design a solution specific to your needs.
Refer to NZS 3109:1997 Table 5.1 for precast construction tolerances.
INSTALLATION & CONSTRUCTION
All Double Tee units come with a camber. Some of this will disappear when the topping concrete is placed. Your Formstress engineer can give you guidance as to how to work with this.
Drilling holes through or cutting precast Double Tees should only be undertaken with the written approval of a Formstress engineer.
In some situations your Double Tee units require bedded on their structural supports. Refer to the shop drawings as to the specific requirements for your project.
GENERAL NOTES
Contact Formstress about any specialist needs you may have.
With a minimum topping of 65mm a STC rating of STC 53 can be achieved (assuming no floor coverings and no ceiling) on a 200 deep Double Tee. This can increase with deeper rib section and floor coverings.
Before manufacture can commence the contractor shall sign off the Formstress shop drawings certifying that the drawings are dimensionally and structurally correct.
All Formstress precast units are provided with lifting eyes. Chains and strops must be of the correct length and not more than 30 degrees of vertical.
For temporary storage of precast Double Tee units provide bearers each end on level ground.
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