PILE & COLUMN REPAIR FORMS
Form-A-Tube®: Snap-Together Forms for Pile and Column Repair
UV-resistant PVC strips, made from recycled material, that snap together on site into a tube of any diameter or length. Leave the tube in place as a jacket around a damaged pile, or strip it off and reuse it as a form for new columns and posts.
- Each strip adds exactly 2 in. to the diameter
- No epoxy, bolts or hardware to assemble
- Stay-in-place jacket or reusable form
TWO WAYS TO USE IT
A Jacket That Stays, or a Form You Reuse
Each strip has a smooth face, a ribbed face with T-shaped profiles, and male and female connectors along its edges. Which face goes inward decides how the tube works.
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Stay-in-Place Jacket
Wrapped around an existing pile or column with the ribs facing it, then filled with grout or concrete. The T profiles lock into the fill, the smooth outside gives a clean finish, and the shell keeps out moisture, the leading cause of corrosion.
Pile repair -
Reusable Form
Assembled with the smooth face inward to cast new columns, posts and footings, or around an existing column to fill an annular space. The smooth face does not bond to concrete, so the strips come off, are cleaned and stored for the next pour.
Column repair
ANY LENGTH, ANY DIAMETER
Build the Tube on Site from Short Strips
Strips of different lengths connect with staggered joints, like tiles, to make a tube of virtually any length. For a 10 ft tall, 12 in. diameter tube, use 15 strips 4 ft long and cut three of them in half. At the bottom, the six strips run 4, 2, 4, 2, 4 and 2 ft. The middle row is all 4 ft. The top row runs 2, 4, 2, 4, 2 and 4 ft.
Short pieces are easy to ship and store. A single pallet of 375 strips, each 8 ft long, holds 3,000 ft of material: enough for 62 tubes 12 in. in diameter or 42 tubes 18 in. in diameter, each 8 ft tall.
Openings can be cut along the height of the tube for pipe penetrations and other attachments. Once connected, the strips also conform to other shapes, such as an oval tube around a group of three piles.
- Staggered joints make any height
- Cut with a fine-tooth blade
- Openings for pipe penetrations
- Oval tubes around pile groups
SIZING
How Many Strips for Each Diameter
The effective width of a strip is 6.28 in. (160 mm), so the tube diameter in inches is always twice the number of strips. In the published repairs, the tube was 4 in. larger than the pile: a 28 in. tube on a 24 in. steel pile, and a 16 in. tube on a 12 in. timber pile.
| Tube diameter | No. of strips required | Strip length per foot of tube height |
|---|---|---|
| 10 in. (254 mm) | 5 | 5 ft |
| 12 in. (305 mm) | 6 | 6 ft |
| 14 in. (356 mm) | 7 | 7 ft |
| 16 in. (406 mm) | 8 | 8 ft |
| 18 in. (457 mm) | 9 | 9 ft |
| 24 in. (610 mm) | 12 | 12 ft |
| 28 in. (710 mm) | 14 | 14 ft |
Planning a pile repair?
Tell us the pile type, diameter, damaged length and water depth. Our team will recommend the right QuakeWrap® system, Form-A-Tube® or PileMedic®, and provide specifications for your engineer.
INSTALLATION
How a Pile Is Repaired with Form-A-Tube®
The installation guide and Form-A-Tube® PDS describe a typical repair. Project requirements vary, and your engineer selects the specification sections that apply.
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Prepare the pile
Remove marine growth, oil, grease and rust by water blasting or sandblasting. Strap PileMedic® spacers around the pile for a uniform stand-off, and skirt pins at the bottom if the repair stops above the mudline.
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Assemble a sheet
Cut strips to length and slide their edges together into a sheet as wide as the tube's circumference. A lubricant such as WD-40 in the female connectors makes sliding easier.
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Wrap and snap
Wrap the sheet around the pile with the T profiles facing it and snap the last edges together. A shell can also be formed above water and lowered to the mudline.
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Secure and seal
Place ratchet straps or shrink wrap every 12 to 18 in. (300 to 450 mm). Seal the bottom of the annular space, for example with foam or a plastic skirt.
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Grout and finish
Fill with PileMedic® Underwater Grout or equivalent by tremie or through ports. Trowel the top to a 2:1 slope and coat it with QuakeBond™ 300SR or 220UR.
Form-A-Tube® at a Glance
- MATERIAL
- UV-resistant PVC, made from recycled material
- COLOR
- Grey
- PANEL SIZE
- 7 in. wide x 0.4 in. thick (178 x 10 mm)
- EFFECTIVE WIDTH
- 6.28 in. (160 mm)
- WALL THICKNESS
- 0.050 in. (1.3 mm)
- LENGTHS
- 4 or 8 ft (1,220 or 2,440 mm) standard; longer custom-made
- WEIGHT
- 0.29 lb/ft (433 g/m)
- ASSEMBLY
- Male and female edge connectors; no epoxy, bolts or hardware
- FILL
- Concrete, grout or another suitable fill material
- SHELF LIFE
- Unlimited, stored indoors away from direct sunlight
MATERIAL DATA
Physical Properties of Form-A-Tube® PVC
| Property | Test standard | Value |
|---|---|---|
| Specific gravity, ±0.02 | ASTM D792 | 1.43 |
| Hardness, Shore D, ±3 | ASTM D2240 | 79 |
| Tensile strength at yield | ASTM D638 | 6,265 psi |
| Tensile modulus | ASTM D638 | 372,000 psi |
| Notched Izod | ASTM D256 | 14.9 ft-lb/in. |
| Heat deflection temperature at 264 psi | ASTM D648 | 162°F |
| Coefficient of linear expansion | ASTM D696 | 3.2 × 10⁻⁵ in./in./°F |
| Flammability | UL 94 | V-0, 5VA |
| Dart drop minimum failure (C.125 TUP) | ASTM D4226 | 2.4 in.-lb/mil |
Advantages of Form-A-Tube®
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Any diameter or length
Built on site from standard strips.
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Easy to ship and store
Flat strips stack on a pallet, unlike fixed-size cardboard tubes.
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Quick to assemble
Strips slide and snap together, and come apart again.
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No epoxy or chemicals
No adhesives, bolts or hardware in the assembly.
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Reusable
Use it many times as a form for new columns and posts.
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Smooth finish
No form marks on finished columns.
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Durable
UV-resistant, weather-resistant PVC.
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Simple to install
Contractors and do-it-yourself dock and marina owners can install it.
Form-A-Tube® or PileMedic®?
Form-A-Tube® forms and protects. PileMedic® laminates also add structural FRP strength. Tell us about the piles and our team will recommend the right QuakeWrap® system.
PROVEN RESULTS
Form-A-Tube® Projects
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Five 24-in. Steel Piles
Corroded at the splash zone in 2019. Fourteen strips special-ordered at 14 ft made 28 in. tubes, strapped at 1 ft spacing and filled with grout.
Watch the video -
Water Pumping Station, Houma, Louisiana
BCG Services repaired the piles of a water pumping station with Form-A-Tube®, and the station kept operating during the repairs. BCG Services president Harvey Sharp gives his testimonial in a client video.
Watch the testimonial -
12-in. Timber Pile
A homeowner repaired a pile rotting at and below ground level with eight 3 ft strips, forming a 16 in. tube filled with concrete.
Form-A-Tube® FAQs
What is Form-A-Tube® made of?
PVC treated with UV protective additives, made from recycled material. It is not an FRP product. Where a pile needs structural FRP strengthening, see PileMedic®.
What lengths are available?
Standard strips are 4 or 8 ft long, and longer strips can be special-ordered. Shorter pieces can be joined with staggered seams to make a tube of virtually any height.
What diameters can I make?
Any even diameter. Each strip adds exactly 2 in., so 6 strips make a 12 in. tube, 7 strips a 14 in. tube, and so on.
Can it be used underwater?
Yes. Form-A-Tube® is used as a stay-in-place form for submerged piles. The shell can be assembled above water and lowered to the mudline, then filled with PileMedic® Underwater Grout or equivalent by tremie or through ports.
How is the bottom of the tube sealed?
Where the repair does not reach the seabed, PileMedic® skirt pins support the tube, and foam or a plastic skirt secured with nylon banding keeps grout from leaking out.
Is Form-A-Tube® resistant to UV?
Yes. The PVC is treated with UV protective additives for a long service life.
How do I order Form-A-Tube®?
Call our team at (520) 791-7000. We will confirm the sizes and quantities you need and take your order over the phone, and we can help you decide whether Form-A-Tube® or PileMedic® is the right fit for your piles.
Related Pages
Have Piles or Columns That Need Repair?
Tell us about the piles or columns and site conditions. Our team will recommend the right QuakeWrap® system and provide specifications for your engineer.