Seismic upgrading of r.c. frame structures using a displacement based design procedure performed with OpenSees

A displacement-based procedure [1] to design dissipative bracing for the seismic protection of frame structures has been developed and some application developed with OpenSees are discussed. The procedure does not require sophisticated dynamic nonlinear analyses but only common non linear static analyses and is based on the displacement based design. Two performance objective have been considered developing the procedure: protect the structure against structural damage or collapse and avoid non-structural damage limiting global displacements and interstorey drifts. The procedure has been tested on case studies of r.c. frame building, considered both bare and infilled, modelled with OpenSees [2]. Infills have been represented by means of single strut elements with a constitutive model calibrated on experimental base [3]: experimental tests have been performed on r.c. portal samples, bare and infilled. The tests have been prepared using OpenSees numerical simulations and, finally, those models have been calibrated in order to obtain reliable numerical models.