|
Title |
Development Length of GFRP Bars
|
|
Keywords |
GFRP 보강근 ; 묻힘길이 ; 피복두께 ; 쪼갬파괴 ; 평균부착응력 GFRP bars ; embedment length ; cover thickness ; splitting failure ; average bond stress |
|
Abstract |
The objective of this study was to propose a development length equation for GFRP bars. A total of 104 modified pullout tests were completed while the test variables were embedment length (15, 30, 45db), net cover thickness (0.5~2.0db), top-cast bar effect, different GFRP bar types (K2KR, K3KR and AsUS), and bar diameters (10, 13, 16 mm). Average bond stresses were determined based on modified pullout test results. Two variable linear regression analysis was performed of the average bond stresses. Utilizing 5% fractile concept, a conservative development length design equation was derived. The design equation derived in this study was compared to the ACI 440 committee equation. The cross-comparison revealed that the current equation resulted in shorter development lengths than those determined by the ACI 440 equation when the net cover thickness was large (greater than 1.0db). On the other hand, when the net cover thickness was small (equal to or less than 1.0db), the development lengths required by the current equation were larger than those by the ACI equation. The bond stresses were significantly influenced by the cover thicknesses. The current equation results in development lengths that are more economical when the cover thickness is large, and more conservative lengths when the cover thickness is small than the ACI 440 committee equation.
|