STRUCTURAL PULTRUSION PROCESS
The pultrusion process is ideally suited for the manufacture of structural shapes. Analogous to the steel rolling process, this process allows structural shapes to be manufactured to length, only restricted by transportation limitations.
Continuous glass fibers that enter the process on the left are actually pulled the length of the process by a tractor (illustrated) or hand-over-hand pullers shown on the right. During the process, the glass bundle of continuous strands is wrapped with continuous strand mats that will provide the transverse strength. The entire reinforcement bundle is then pulled into a liquid resin bath (polyester or vinyl ester) and "wetted" out. The wetted reinforcement package is wrapped in a surfacing veil, which allows a resin-rich finish on the part, offering a first barrier to corrosion and a smooth finish. The completed package then goes into a performer that roughly forms the package into the appropriate shape to enter the heated die for curing. The die is the exact shape of the final part desired. Upon exiting the die, the part is over 90% cured and solid. The length of the part required is pulled through the cutoff saw and the process is complete.
STRUCTURAL SHAPES
NANTONG MACHS' manufactures all standard shapes used for structural projects. They are manufactured in both vinyl ester (standard color is beige) and polyester (standard color is dark gray). Embedment angles are only manufactured in vinyl ester and standard in dark gray to compliment the color of concrete. Reference AGL's Availability List on the following page for a complete list of structurals provided.
1. All structural shapes are to be manufactured by the pultrusion process with a glass content minimum of 45%, maximum of 55% by weight. The structural shapes shall be composed of fiberglass reinforcement and resin in qualities, quantities, properties, arrangements and dimensions as necessary to meet the design requirements and dimensions as specified in the Contract Documents.
1. Fiberglass reinforcement shall be a combination of continuous roving, continuous strand mat, and surfacing veil in sufficient quantities as needed by the application and/or physical properties required.
1. Resins shall be {MACHS® ISO, non-fire retardant isophthalic polyester or ISO, non-fire retardant isophthalic polyester used to produce Standard 61 certified shapes; ISOFR, fire retardant isophthalic polyester; VE, non-fire retardant vinyl ester used to produce Standard 61 certified shapes or VEFR, fire retardant vinyl ester, (choose one)} with chemical formulation necessary to provide the corrosion resistance, strength and other physical properties as required.
1. All finished surfaces of FRP items and fabrications shall be smooth, resinrich, free of voids and without dry spots, cracks, crazes or unreinforced areas. All glass fibers shall be well covered with resin to protect against their exposure due to wear or weathering.
1. All pultruded structural shapes shall be further protected from ultraviolet (UV) attack with 1) integral UV inhibitors in the resin and 2) a synthetic surfacing veil to produce a resin rich surface.
1. All fire retardant FRP products shall have a tested flame spread rating of 25 or less per ASTM E84 Tunnel Test.
1. All shapes products shall be certified to /ANSI Standard 61 {use only if choosing a resin system that can be used to produce shapes to the Standard 61 in sections 2.2 C}
2.3 Pultruded structural shapes are to have the minimum longitudinal mechanical properties listed below:
| Property | ASTM Method | Value | Units |
| Tensile Strength | D-638 | 30,000 (206) | psi (MPa) |
| Tensile Modulus | D-638 | 2.5 x 106 (17.2) | psi (GPa) |
| Flexural Strength | D-790 | 30,000 (206) | psi (MPa) |
| Flexural Modulus | D-790 | 1.8 x 106 (12.4) | psi (GPa) |
| Flexural Modulus (Full Section) | N/A | 2.8 x 106 (19.3) | psi (GPa) |
| Short Beam Shear (Transverse) | D-2344 | 4,500 (31) | psi (MPa) |
| Shear Modulus (Transverse) | N/A | 4.5 x 105 (3.1) | psi (GPa) |
| Coefficient of Thermal Expansion | D-696 | 4.4 x 10-6
(8.0 x 10 -6) | in/in/°F
(cm/cm/°C) |
| Flame Spread | E-84 | 25 or less | N/A |
PART 3 EXECUTION
3.0 FABRICATION
1. Measurements: Structural Shapes supplied shall meet the minimum dimensional requirements as shown or specified. The Contractor shall provide and/or verify measurements in field for work fabricated to fit field conditions as required by manufacturer to complete the work. Determine correct size and locations of required holes or coping from field dimensions before structural shape fabrication.
1. Sealing: All shop fabricated cuts or drilling shall be coated with vinyl ester resin to provide maximum corrosion resistance. All field fabricated cuts or drilling shall be coated similarly by the contractor in accordance with the manufacturer's instructions.
1. Hardware: Type 316 stainless steel bolts shall be provided.
3.1 INSPECTION
Shop inspection is authorized as required by the Owner and shall be at Owner's expense. The fabricator shall give ample notice to Contractor prior to the beginning of any fabrication work so that inspection may be provided. The structural shapes shall be as free, as commercially possible, from visual defects such as foreign inclusions, delamination, blisters, resin burns, air bubbles and pits.