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Early form release for two-way slabs

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I am working on a project which has a 12 " thick, two-way flat slab system. The contractor is proposing to use a forming system that offers an early release of the beam and girder forms. The way the system works is there are shores at 6'-0" on center each way with a beam and girder system supporting the plywood at 16 or 24" o.c.. The forming manufacturer has made recommendations for an early release of the beam and girder system but leaving the vertical supports in place until the concrete has reach the required strength. They have a one day release time specified for a 12" slab as long as the min. compressive strength is 500 psi. Basically they consider the slab to be a 2-way slab supported at 6'-0" o.c.e.w., unreinforced. They have analyzed the slab based on the modulus of rupture to determine the early release time. I have looked through the ACI Manual and have only found the section which requires forms for horizontal surfaces to remain in place until the concrete has reached 70% of the required compressive strength. I guess I have the following questions:
 
1. Is this type of early release system allowed per code.
2. Is the method of analysis described above acceptable per ACI utilizing the modulus of rupture.
3. Can anyone point me to a portion of the code which would allow such a system to be used without achieving the 70% f'c.
  
I would appreciate any information anyone could provide me regarding this matter.
 
Thank You,
Keith E. Pabst, E.I.T.
Highland Associates, Ltd.
Architects Engineers Interior Designers
102 Highland Avenue
Highland Center
Clarks Summit, PA  18411
(570)586-4334
(570)587-8164 fax
email: kpabst(--nospam--at)ha-pa.com