Seismic vulnerability assessment of a mixed masonry-RC building aggregate by linear and nonlinear analyses.

From the beginning of the twentieth century, and due to the rapid increase of reinforced concrete (RC) usage, mixed masonry-RC buildings have emerged. In Lisbon, Portugal, old mixed masonry-RC buildings appeared between 1920 and 1960, representing the transition period between masonry and proper RC. These buildings are often integrated in blocks, and frequently share the side-walls, implying, thus, the need to assess the seismic vulnerability of building aggregates. The present paper approaches the seismic vulnerability assessment of a specific type of old mixed masonry-RC buildings in Lisbon. The study comprises the analysis of a building, both as an isolated structure and inserted in its aggregate, using two approaches: (1) linear dynamic analysis with SAP2000 and (2) nonlinear static analysis by means of 3Muri/Tremuri software. A comparison of both approaches derives a good matching between the obtained results. However, a nonlinear analysis is required to identify, in an adequate manner, the critical areas of the structure requiring strengthening. [ABSTRACT FROM AUTHOR]