Hamilton Form, Ltd.
7009 Midway Road
Fort Worth, TX 76118

Phone: 817 590-2111
Fax: 817 595-1110
sales@hamiltonform.com

PCI NPCA CPCI

Frequently Asked Questions

How do we install and anchor long-line, vessel type steel forms?

To achieve optimal results, long-line steel forms should be installed and anchored properly. The following guidelines should be followed; however, each form and each plant is different. Contact Hamilton Form if you have any further questions.

If not properly installed, use of steel forms can be very dangerous and can result in destruction of the form, possible serious personal injury or death.

  1. Prepare the area where the form will be installed, making sure it is clean and level. Install beams or anchor plates as required. Refer to the form drawings for the longitudinal and transverse support points required for your form.
  2. If the form is being installed outside, the orientation of the form should be taken into consideration. Long-line forms should be installed east and west whenever possible. When a form is installed north and south, the side of the form facing the morning sun usually expands more than the side that is shaded. As a result, some temperature related expansion problems are likely to occur. We have noticed that this problem is even more noticeable at higher elevations.
  3. Move form sections according to the layout to the designated area of the plant using the marked lifting locations located on each section. Always use these locations when lifting sections.
  4. The form must be installed straight and in a flat plane with no more than +/- 1/16th inch variation.
  5. Most producers install their forms level, however some producers have installed forms with a slight slope from end-to-end to allow for drainage.
  6. Do not use the outer edge of the form for alignment. You will notice that the edges of forms frequently have structural angles or channels for added stiffness. These structural steel shapes can have mill tolerances that are too large to make them acceptable to use as a line of reference to align a form.
  7. On all forms, alignment should always be taken from your most critical point such as the top edge, inside skin or centerline skin seam.
  8. In aligning a double tee form, the centerline skin seam at the centerline of the form is the most true reference line.
  9. Your form was built level from the casting surface. Due to steel tolerances, the bottom understructure may vary in height. Therefore, the form must be shimmed level or in a plane, using the casting surface as reference for final shimming.
  10. After the form is leveled and in place, check the level again and shim as necessary. Shim packs should be accurately "shot in" for proper elevation and double checked from the skin surface. If the form is not installed in a flat plane, castings will not be square, stripping may be difficult and damage to the product and the form may occur.
  11. After final leveling, pull all joints tight together. There are a number of ways to pull the joints together, be sure that as you pull the joints together, the form remains straight and level or on a plane.
  12. Anchor the center of the form. A long-line form should be permanently anchored at the center 5 or 10 feet. This forces the movement of the form due to stressing, detensioning and from expansion and contraction due to temperature changes to each end of the form, splitting the movement in half.
  13. The remainder of the form must be clipped down to provide resistance to uplift forces and maintain alignment while allowing the form to expand and contract longitudinally. Most forms should be shimmed and clipped down on 5-foot centers. For self stressing forms, we recommend that the clips be on 30" centers for the end 10 feet of the bed.
  14. There are several ways that forms can be clipped down. Remember, the ability of the form to move as it expands and contracts is very important. Periodic inspections and maintenance of the anchoring details is required to assure that the form is performing properly. If the form is not allowed to expand and contract it can buckle and/or open at the joints so that the form is not straight. When this happens, stripping becomes difficult and the form and product may become damaged.
  15. Install lap plates to mechanically connect the form together. Lap plates are typically welded on the outside structure of the form (longitudinal members) at the top and bottom. Self stressing forms should be partially prestressed before the final lap plates are installed.
  16. Before the first pour you may want to oil and heat the form to season the casting surface. Never leave the casting surface unprotected from the elements. Rust forms very quickly on steel surfaces.