Novel Filament‐Wound FRP Composite Tubes Integrated Grid Ribs and Multi‐Angle Winding Layer: Manufacturing, Interfacial Behavior and Proof‐of‐Concept Validation

Interfacial slip between concrete and fiber‐reinforced polymer (FRP) tubes remains a key concern in concrete‐filled FRP tube members. This study proposes a novel concrete‐filled FRP tube integrated with designable grid ribs and multi‐angle winding layers (GR‐CFFT). The internal grid ribs are intended to enhance rib–concrete mechanical interlocking, reduce interfacial slip, and improve the contribution of longitudinal reinforcement layers to flexural resistance. The proposed tube was fabricated using an automated filament winding process, enabling integrated rib formation and efficient manufacturing. Depending on the rib location within the tube wall, this concept can be extended to outer‐rib or double‐rib configurations for different anchorage requirements. As a proof‐of‐concept study, the inner‐rib configuration was evaluated through push‐out and four‐point bending tests. Compared with reference specimens without grid ribs and longitudinal reinforcement layers, the GR‐CFFT specimens showed a 22‐fold increase in apparent interfacial shear strength, a 393% increase in flexural capacity, and a 90% reduction in average end slip. An ABAQUS/Explicit model was established, and a numerical sensitivity study was conducted on rib presence, width, and angle. The observed enhancement reflects the combined effects of grid ribs and multi‐angle winding layer configuration.