Fiberglass Concrete Form Ties

Form-tie assemblies for architectural concrete should permit tightening of forms and leave no metal closer to the surface than I-1/2 inches (38 mm) for steel ties and 1 inch (25 mm) for stainless tell ties. The ties should not be fitted with lugs, cones, washers, or other devices that will leave depressions in the concrete less than the diameter of the device, unless specified. Ties should be tight fitting or tie holes in the form should be sealed to prevent leakage at the holes in the form. If texture surfaces are to be formed, ties should be carefully evaluated as to fit, pattern, grout leakage, and aesthetics.

Ties and Inserts

Form ties and accompanying tie holes are an almost inescapable part of wall surface. Architects frequently tie holes into the visual design quality of the surface. If this is planned and any effects or materials other than those provided in the upper heading are desired, they should be clearly specified as to both location and type.

Where tie holes are to patched or fitted, the architect should specify the treatment desired, unless it has been shown on the pre-construction mock up.

Fiberglass Reinforced Concrete

Fiberglass reinforced concrete is composed of cement-rich concrete or mortar modified with additive and reinforced with alkali-resistant glass fibers. Colors is provided by the cement and aggregated used in the mix, or from a small proportion of added pigment. The material is sprayed or poured into forms to create thin-shelled panels, 12.7 to 15.8mm (1/2 to 5/8 in) thick with an anchorage system embedded in the fiberglass reinforced concrete. The panels, which can be left uncoated or painted, are erected on concrete or steel structural frames. 

Fiberglass Reinforced Concrete is a relatively recent (30 years) technological development. It has been used primarily for architectural claddings. The combination of glass fibers with concrete technology has created its own set of issues to be addressed, including loss of strength, embrittlement of the glass fibers, and variable expansion and contraction characteristics.

Fiberglass reinforced concrete has the following advantages;

1. The material is lightweight compared to cast stone, terra cotta, and precast concrete, and is therefore   easier to handle during installation.
2. Fiberglass reinforced concrete can be readily molded into panels with intricate details. Because it adapts easily to molding. Section of repetitive design or sculptural element can be produced efficiently.
3. Less shrinkage occurs during fabrication than with terra cotta or cast metal. It may therefore be possible to make molds for fiberglass reinforced concrete units directly from the existing elements to be replicated.
4. Fiberglass reinforced concrete is vapor permeable, and therefore moisture that enters the unit   can escape. This mitigates the potential for damage to occur from entrapped moisture.
5. Fiberglass reinforced concrete is fire resistant.