504 EM 385-1-1 Sections 27-34

27.C.12 Vertical slip forms.

2. The steel rods or pipe on which the jacks climb or by which the forms are lifted must be designed specifically for that purpose. Such rods must be braced where not encased in concrete.
3. Jacks and vertical supports must be positioned in such a manner that the vertical loads are distributed equally and do not exceed the capacity of the jacks.
4. The jacks or other lifting devices must be provided with mechanical dogs or other automatic holding devices to provide protection in case of failure of the power supply or the lifting mechanism.
5. Lifting must proceed steadily and uniformly and must not exceed the predetermined safe rate of lift.
6. Lateral and diagonal bracing of the forms must be provided to prevent excessive distortion of the structure during the jacking operation.
7. During jacking operations, the form structure must be maintained in line and plumb.
8. All vertical lift forms must be provided with scaffolding or work platforms completely encircling the area of placement.

27.C.13 Removal of formwork.

27.D Precast Concrete Operations.

27.D.01 Precast Concrete operations must be planned and designed by a RPE. Precast Concrete Plans and designs must include detailed instructions and sketches indicating the prescribed method of erection and must be submitted to the GDA for review.

27.D.02 Precast concrete members must be adequately supported to prevent overturning or collapse until permanent connections are complete.

27.D.03 Lifting inserts and hardware.

1. Lifting inserts which are embedded or otherwise attached to tilt-up precast concrete members must be capable of supporting at least two times the maximum intended load applied or transmitted to them.
2. Lifting inserts which are embedded or otherwise attached to precast concrete members, other than tilt-up members, must be capable of supporting at least four times the maximum intended load applied or transmitted to them.
3. Lifting hardware must be capable of supporting at least five times the maximum intended load applied or transmitted to the lifting device.

27.D.04 No employee must be permitted under precast concrete members being lifted or tilted into position except employees required for the erection of those members.

1. Forms and shores (except those on slab or grade and slip forms) shall not be removed until the individual responsible for forming and/or shoring determines that the concrete has gained sufficient strength to support its weight and all superimposed loads. Such determination shall be based on one of the following:
• (1) Satisfaction of conditions stipulated in the plans and specifications for removal of forms and shores, or
• (2) Concrete testing (in accordance with ASTM standard test methods) indicates that the concrete has achieved sufficient strength to support its weight and superimposed loads.
2. Re-shoring shall not be removed until the concrete being supported has attained adequate strength to support its weight and all loads placed on it.

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