Preliminary results on sheared granular medium display inverse rate-dependence of bulk stresses and packing fraction, while under constant gap and constant stress respectively. The experimental result captures the Bagnold regimes consistently with association to the Savage number effect (inertial vs. compressive forces). Within intermediate deformation rates, defined as between quasi-static and grain-inertial regimes, the material exhibits a “weakening” behavior that has never been experimentally observed. Particularly, experimental data shows a Gaussian-like rate dependence of the macroscopic properties. To explain this peculiar event, the rate-dependent localized flow, i.e. formation of clusters and force chains, is proposed as the dominant grain-grain contact mechanics during this transitional regime.š Furthermore, the Jenkins and Savage constitutive stress relation is utilized as the basis of the proposed equation of state. The proposed model predicts the present experimental data, including the minimum values for both bulk stress and packing density, for a mobilized granular medium. Rate-independent friction coefficient is recovered from the ratio of the normal and shear stress data, and its value is 25% larger than the internal friction angle for the sheared material.