Wide‐Temperature Anchorage Behavior and Design of Variable‐Stiffness Bonded Anchor for Ribbed CFRP Bar

ABSTRACT

Variable‐stiffness load transfer components (LTCs) mitigate stress concentration in bonded CFRP anchors, yet their wide‐temperature behavior remains unclear. This study proposes a three‐segment bonded anchorage system incorporating high‐performance epoxy adhesive modified with 200‐mesh quartz sand to tailor the stiffness distribution of the LTC. Monotonic tensile tests were conducted on 62 specimens, covering three stiffness‐ratio distributions (LTC1–LTC3), three bond lengths (200–300 mm), and four temperatures (−20°C, 0°C, 20°C, and 70°C). A finite element model using connector elements and the LaRC05 failure criteria was validated against experimental data and subsequently employed for parametric investigations on sleeve outer diameter and segment length ratio. Experimental results indicate that at 20°C, LTC3 achieved an average equivalent shear stiffness of 410.95 kN/mm, 1.84 and 1.68 times that of LTC1 and LTC2, respectively, and showed a clear bond‐length enhancement effect. At 70°C, stiffness deteriorated markedly; however, LTC3 with a 250 mm bond length maintained K  = 60.00 kN/mm, produced a more uniform shear stress distribution, and delivered anchorage efficiency above 95% across the investigated temperatures. An optimized configuration (outer diameter 45 mm; segment ratio 1:2:3) reduced stress concentration and lowered the matrix damage index by 16.6% under room‐temperature conditions.