Over
the past several years, extensive research has studied the serviceability of
concrete members reinforced with internal FRP bars. Numerous experimental tests
have been conducted and there exists an extensive body of data in the literature
on deflections and crack widths observed during such tests. This work has
resulted in the continuous development of design guidelines published by the
American Concrete Institute (ACI) Committee 440 and the Canadian Standards
Association (CSA). However, there is a relative lack of data on the behavior of
flexural members subjected to sustained service-level loading. The ACI and CSA
design guidelines clearly indicate the need for additional research in this
area, particularly since the design of FRP-reinforced concrete is often
governed by serviceability. This paper reports the results of an experimental
test program is which six beams (two steel, two GFRP, and two CFRP) were
maintained under a constant load for a period of 90 days. Measured flexural
crack widths and midspan deflections are reported over the duration of the test
period. Measured data is compared to the limited results available from other
published studies and to the current ACI and CSA provisions.