where P is the applied load; Ee is the elastic modulus of the concrete; 8 is the midspan deflection; l and a are the span length and shear span of the beam, respectively; and lg is the gross moment of inertia of the beam section at midspan. It is important to note that Eq. (1) is valid until yielding of the beams and the graphs of Fig. 5(b) represented an elastic range accordingly. The control beam depicted a noticeable drop of le immediately after its cracking load and tended to stabilize at around le = 15 x 106 mm4 (36.0 in.4 with an increasing load. The strengthened beams revealed a similar response; however, their le values were higher than that of the control, as shown in Fig. 5(b). There was no remarkable difference in the effective moment of inertia between the beams with one- and two-strip CFRP.