Reliability assessment on maximum crack width of GFRPreinforced concrete beams

ABSTRACT

The suggested provisions in guideline ACI 440.1R-06 for predicting the maximum crack width of GFRP-reinforced concrete beams are assessed from the probabilistic point of view by the Rackwitz-Fiessler method. The assessment indicates that the global average reliability index is 0.57, meeting the target reliability index of serviceability ultimate state. Effective height-to-height ratio, d/h, width, b, and height-to-width ratio, h/b, are the first three dominating influencing factors on reliability level. The average reliability index is basically independent of relative FRP reinforcement ratio, η. The effect of load effect ratio, α, on reliability level is also significant and the index tends to converge at β=0.58. The parametric study on the bond-dependent coefficient, kb, indicates that its mean does not put any effect on reliability level while its C.O.V. is rather significant. As the C.O.V. of kb increases from 0.05 to 0.20, the average index decreases from 0.53 to 0.41. The limit of the maximum crack width, [w], is shown to be no relations with reliability level. Specification on the limit of maximum allowable crack width is dependent only on the consideration of durability and visible tolerance