Fiberglass reinforced concrete domes
What is GFRC (Glass Fiber Reinforced Concrete)
Glass fiber reinforced concrete ( GFRC ) also called GRC or FRC is a cementitious, composite material, cast in thin shell shapes for use in construction. Consisting of Portland cement, aggregate, water, alkali-resistant glass fibers, polymer and additives, the GFRC mix design is custom engineered depending on the requirements of the GFRC project and the GFRC part.
Advantages of GFRC (Glass Fiber Reinforced Concrete) Domes
- GFRC is made of minerals and will not burn.
- GFRC is relatively light in weight compared to traditional stone or terra cotta ornaments. Its installation is quick and relatively easy.
- GFRC domes can be cast to virtually any shape.
- GFRC domes can be made either with a cast in integral color and texture: limestone, precast concrete, acid wash, etc. or as paint grade that is easily finished with virtually any paint.
Constructing GFRC Domes
Large GFRC (glass fiber reinforced concrete) domes are generally cast in pie shaped segments, and assembled on-site. Smaller domes, generally less than eight to 10 feet diameter, may be cast as one piece units, or in segments. If the dome is a decorative element to be viewed from the exterior only, the roof is put in place, and the dome placed above it. Similarly if the dome is to be viewed from the interior only, it may be suspended from the ceiling structure above it. If the domes are to be viewed from both the interior and the exterior than a double dome is required with insulation placed between the inner and outer dome. Exterior glass reinforced concrete domes may be molded smooth or textured, with ribs or even with the molded in shape of roof tile, or glazed mosaic tile. Interior domes in GFRC (glass fiber reinforced concrete) may be smooth, ribbed, or coffered. In some applications both an exterior dome of GFRC or fiberglass, and an interior dome of GFRC or fiberglass are used. Between the inner dome and outer dome, the dome cavity may be insulated.
| Feature | Benefit | Advantage |
|---|---|---|
| Stromberg GFRC Domes provide quick on-site construction and assembly. | Stromberg GFRC domes arrive at the jobsite in one piece (for small domes) or in pie shaped sections. Each dome section has a turned down flange to allow it to be bolted to the next section. | GFRC speeds the construction process and reduces the associated costs. |
| Stromberg GFRC domes are low cost | Stromberg GFRC domes are generally lower in cost than site built domes, concrete air form domes, masonry domes and other dome construction methods.no system gives you a better value for your money | GFRC domes by Stromberg provide real value for the money. |
| Stromberg GFRC domes are rot resistant | Unlike wood or foam, GFRC does not rot. | You save maintenance costs as GFRC Domes allow you to avoid the costs and inconvenience of rot that plague other materials. |
| Stromberg GFRC Domes do notrust | GFRC does not rust.In severe environments, the GFRC dome can be designed with no metal components. | No rust to deal with |
| GFRC domes by Stromberg are environmentally friendly | The main ingredients of GFRC are based on the plentiful and naturally occurring minerals. These natural materials are not normally regarded as pollutants. GFRC itself is a stable mineral based material, and is inert. | Environmentally friendly. |
| Flame, flood & earthquake resistant | The resilience of GFRC allows it several advantages in earthquake conditions. It holds up to floods. It will NOT burn. | May reduce insurance costs. Reduces risk from water, wind and fire. |
What is GFRC and what is a GFRC dome?
GFRC (glass fiber reinforced concrete) is concrete that uses glass fibers for reinforcement instead of steel. It is typically cast in a thin section of around 1/2" to 3/4". Since the fibers cannot rust like steel, there is no need for a protective concrete cover thickness to prevent rusting. With the thin, hollow construction of GFRC products, they can weigh a fraction of the weight of traditional precast concrete or stone.
How strong is GFRC?
As an engineered material, the properties of GFRC can vary depending upon mix design, glass content and production methods. Glass fiber used in quality GFRC has a higher tensile strength than steel. As a general rule, the higher the fiber content, the higher the strength. A typical GFRC mix with 5% glass fiber has a flexural modulus of elasticity of around 1.5 to 2.9 X10 6 and compressive strength of 6,000 to 8,000 psi.
How durable is GFRC?
GFRC has been tested both by accelerated aging tests in the laboratory and in real life installations. GFRC can be expected to last as long as pre-cast concrete. In many environments, as when exposed to salt spray or high moisture, the GFRC can be expected to perform better, as there is no steel reinforcement to corrode. Since the surface of GFRC is a Portland concrete, it weathers much as a quality architectural pre-cast concrete would.
How is GFRC attached?
Most GFRC domes can be divided into two categories: with internal frame and without. GFRC with an internal frame is for larger pieces and panels. The internal frame allows for what would have been multiple pieces of terra-cotta , to be installed in one large unit. GFRC without the internal frame is generally set one piece at a time, much the way terra-cotta would have been. This is useful in cases where not all of the terra-cotta needs to be replaced.
