Abstract: Axially extending structures having internal forces directed radially outward therefrom may be reinforced by installing bands around the structures. The bands consist of a plurality of elastic convolutions of a composite material which assume a coiled configuration in a relaxed condition. The composite material includes a multiplicity of continuous, high tensile strength filaments encapsulated in a resin matrix and extending codirectionally with one another through the resin matrix. The band is installed around the structure by deflecting portions of the band to an uncoiled configuration and then wrapping these portions of the band around the structure. Adhesive may be used to secure the band tightly around the structure. Particularly useful applications for the composite bands are for reinforcing gas and liquid transmission pipelines and concrete bridge support columns.

Abstract: Spiral bands having a plurality of convolutions of a high tensile strength composite material are formed by feeding a plurality of continuous high tensile strength fibers through an uncured resin to form a web, depositing the web on a release web having at least one substantially flat surface to form a laminate, winding the laminate around the mandrel to form a plurality of overlapping convolutions, curing the resin in the composite web to set the convolutions in a spiral configuration, and then removing the release web from the composite web. The convolutions of the spiral bands in accordance with this process have substantially flat surfaces and an elastic memory. These bands can be used to reinforce axially extending structures having internal forces directed radially outward therefrom by wrapping the band around the structure with a layer of adhesive applied to hold the convolutions in place.

Abstract: Spiral bands having a plurality of convolutions of a high tensile strength composite material are formed by feeding a plurality of continuous high tensile strength fibers through an uncured resin to form a web, depositing the web on a release web having at least one substantially planar surface to form a laminate, winding the laminate around the mandrel to form a plurality of overlapping convolutions, curing the resin in the composite web to set the convolutions in a spiral configuration, and then removing the release web from the composite web. The convolutions of the spiral bands in accordance with this process have substantially planar surfaces and an elastic memory. These bands can be used to reinforce axially extending structures having internal forces directed radially outward therefrom by wrapping the band around the structure with a layer of adhesive applied to hold the convolutions in place.