  Electrostatic gating offers elegant ways to simultaneously strain and dope
atomically thin membranes. Here, we report on a detailed \textit{in situ} Raman
scattering study on graphene, suspended over a Si/SiO$_2$ substrate. In such a
layered structure, the intensity of the Raman G- and 2D-mode features of
graphene are strongly modulated by optical interference effects and allow an
accurate determination of the electrostatically-induced membrane deflection, up
to irreversible collapse. The membrane deflection is successfully described by
an electromechanical model, which we also use to provide useful guidelines for
device engineering. In addition, electrostatically-induced tensile strain is
determined by examining the softening of the Raman features. Due to a small
residual charge inhomogeneity $\sim 5\times 10^{10}~\rm cm^{-2}$, we find that
non-adiabatic anomalous phonon softening is negligible compared to
strain-induced phonon softening. These results open perspectives for innovative
Raman scattering-based readout schemes in two-dimensional nanoreso
