Effective Moment of Inertia of Reinforced Concrete and Reinforced Steel Fiber-Reinforced Concrete One-Way Slabs

An effective moment of inertia (Ie) unified for reinforced concrete was presented. Two model parameters for the degree of tension stiffening and plasticization of concrete in compression (PZC), where the relationships of concrete stresses and strains deviate from its linear elastic stage, were calibrated using 26 test results of RC and RSFC slabs, including eight slabs tested in this study for three different reinforcement ratios (rho) and fiber contents (Wf). Comparisons with test results revealed that underestimated deflections were predicted with the Ie currently adopted as basic formats in different codes, for RC slabs having relatively lower or higher rho values and RSFC slabs with wide ranges of rho typical to one-way slabs. However, regardless of the magnitudes of rho and Wf, reasonable deflections were predicted with the unified Ie, which was constituted with linearized weight functions of the ratio of cracking moment to moment in service and modified to include the effects of rho, PZC, and Wf.