  We study infrared contributions to semihard parton-parton interactions by
considering an effective charge whose finite infrared behavior is constrained
by a dynamical mass scale. Using an eikonal QCD-based model in order to connect
this semihard parton-level dynamics to the hadron-hadron scattering, we obtain
predictions for the proton-proton ($pp$) and antiproton-proton ($\bar{p}p$)
total cross sections, $\sigma_{tot}^{pp,\bar{p}p}$, and the ratios of the real
to imaginary part of the forward scattering amplitude, $\rho^{pp,\bar{p}p}$. We
discuss the theoretical aspects of this formalism and consider the
phenomenological implications of a class of energy-dependent form factors in
the high-energy behavior of the forward amplitude. We introduce integral
dispersion relations specially tailored to relate the real and imaginary parts
of eikonals with energy-dependent form factors. Our results, obtained using a
group of updated sets of parton distribution functions (PDFs), are consistent
with the recent data from the TOTEM, AUGER and Telescope Array experiments.
