Cultural Heritage RC Structures Environmentally Degradated: Optimal Seismic Upgrading by Tention-Ties Under Shear Effects.

A computational approach is presented for the seismic response of existing Cultural Heritage industrial reinforced concrete (RC) structures, which have been degraded due to extreme actions (environmental, seismic etc.) and are to be seismically upgraded by using cable elements (tension-ties). Emphasis is given to shear effects, which are common for old RC buildings not designed according to new (after 2000) seismic codes concerning Civil Engineering praxis. The unilateral behavior of the cable-elements and the non-linear behavior of the RC structural elements are strictly taken into account and result to inequality constitutive conditions. For the numerical treatment of the system of partial differential relations (PDE), a double discretization, in space by the Finite Element Method and in time by a direct incremental approach, is used. So, in each time-step, a non-convex linear complementarity problem is solved. The decision for the optimal cable-strengthening scheme under seismic sequences is obtained on the basis of computed damage indices, as shown in a numerical example.