The mechanics of systems of non-cross-linked fiber networks is studied in this work using a computational model inspired from the bead-spring models of polymeric melts. The fibers have random orientation and distribution in space, interact via stiff repulsive potentials and are characterized by their axial and bending stiffness. Fiber-fiber Coulombian friction is considered. The system is subjected to isostatic compression (strain control) and various statistical measures are evaluated. As the system is compacted, a critical density is reached at which stiffness develops. At this stage there is in average one fiber-fiber contact per fiber and the fiber free segment length has a uniform probability distribution function. Upon further compaction, the number of contacts per fiber increases and the segment length distribution becomes exponential. The respective cross-over densities depend on the fiber length and the friction coefficient. Significant hysteresis is observed upon loading-unloading in the total energy and the number of contacts per fiber. It is also observed that the distribution of contact energies in the range of densities where the system forms a topological network is a power law.