Displacement-based design procedure of grouted anchoring systems for the seismic upgrade of heritage buildings

Abstract

A displacement-based design procedure is proposed to control the out-of-plane motion of masonry walls during seismic events by means of a Grouted Anchoring System (GAS) and a Dissipative Grouted Anchoring Systems (D-GAS). Combining the non-linear static capacity of walls in three different configurations (unstrengthened, strengthened with GAS or D-GAS) with the inelastic demand spectra gives the expected performance of the system, which is then compared to a set of damage thresholds corresponding to the progression from linear to nonlinear behaviour of the system. The design method is validated comparing the expected performance with the evolution of the wall’s rocking motion obtained by means of time-history analysis for a seismic acceleration adapted to the design spectrum used in the static analysis. The results highlight that the D-GAS provides the optimal design solution as it controls the amplitude and acceleration of the rocking motion while dissipating the seismic energy through friction. This allows for a reduced number of required anchors, thus a less invasive of the intervention, which is beneficial especially for applications to historical building with aesthetic value.