The Effect of Structural Uncertainties of Steel Shear Wall on Seismic Performance of Rehabilitated Moment Frame

Uncertainties are inevitable in the estimation of structural engineering issues and increase the cost of retrofitting. In the presence of uncertainties, the results of seismic evaluation are incorrect and create conservatism in acceptance criteria at structural performance levels. Considering and quantification of uncertainties in design and rehabilitation of structures reduces the existing conservatism and can lead to the economic design and rehabilitation of structures. In the seismic rehabilitation of structures, uncertainties have been studied on existing structures and have been applied by coefficients in guidelines. Adding a secondary system to rehabilitate of existing structure can enter uncertainties into the computation and can be effective for results of reliability. Therefore, in this study, reliability of rehabilitated steel moment frame with steel shear wall has been discussed in order to quantify the uncertainty of the steel shear wall. The selected structure is a nine-storey steel moment frame of SAC project, which was rehabilitated by steel shear wall. The studied structures were analyzed pre- and post-rehabilitation, with probabilistic variables considered for steel shear wall by OpenSees software. Based on results of incremental dynamic analysis and obtained fragility curves, the values of the reliability index have been obtained for the rehabilitated structure in the presence of uncertainties. Results showed that considering of uncertainties and reducing them can reduce the existing conservatism and the cost of rehabilitation.