Abstract: A duct bank for enclosing utility lines underground includes a first main duct formed from a nonmetallic material. The first main duct defines an interior volume therewithin and has a circular cross-sectional shape. The duct bank further includes a plurality of sub-ducts each formed from a nonmetallic material and being disposed in the interior volume of the first main duct. Each of the plurality of sub-ducts has a circular cross-sectional shape and is configured to carry one or more utility lines. The nonmetallic material of the first main duct includes one or more of: glass reinforced polyester (GRP), a hybrid fiber-reinforced epoxy-based laminate, or glass-reinforced vinyl ester. The nonmetallic material of each of the plurality of sub-ducts includes one or more of: GR, high-density polyethylene (HDPE), or polyvinyl chloride (PVC).

Abstract: This disclosure describes a reinforced thermosetting resin piping system that is protected from external impact and UV damage by an outer polyurea-based layer. The embodiments described herein can be favorably used for underground and aboveground applications. In some implementations, an RTR pipe includes a core layer that includes a resin and fibers, an outer layer that includes a polyurea-based layer, and an interface layer between the core layer and the outer layer. The methods described herein also outline the process of producing the pipe structure.

Abstract: This disclosure describes a reinforced thermosetting resin piping system that is protected from external impact and UV damage by an outer polyurea-based layer. The embodiments described herein can be favorably used for underground and aboveground applications. In some implementations, an RTR pipe includes a core layer that includes a resin and fibers, an outer layer that includes a polyurea-based layer, and an interface layer between the core layer and the outer layer. The methods described herein also outline the process of producing the pipe structure.

Abstract: Methods, apparatus, devices, and systems for clamping hollow structures with multi-sectional composite clamps are provided. In one aspect, a method includes: sequentially clamping at least two clamp layers around the hollow structure by clamping a first clamp layer around the hollow structure by connecting one or more clamp sections of the first clamp layer to form at least one first joint and clamping a second clamp layer around the first clamp layer by connecting one or more clamp sections of the second clamp layer to form at least one second joint. The at least one second joint and the at least one first joint mismatch with each other around the hollow structure.

Abstract: This disclosure describes a reinforced thermosetting resin piping system that is protected from external impact and UV damage by an outer polyurea-based layer. The embodiments described herein can be favorably used for underground and aboveground applications. In some implementations, an RTR pipe includes a core layer that includes a resin and fibers, an outer layer that includes a polyurea-based layer, and an interface layer between the core layer and the outer layer. The methods described herein also outline the process of producing the pipe structure.