| This research studies the dynamic torsional response of buildings to seismic actions. The focus is on framed buildings with non linear behavior of their components. One and three story buildings are studied, and they are idealized using simplified models made of four plane frames. The research is divided in two stages. First, the response of single buildings to a single seismic action is evaluated to find their patterns of behavior. The instant eccentricity is compared with the static eccentricity, and the instant effective torsional moment with the nominal torsional moment, to evaluate the usefulness of the static eccentricity to predict the maximum torsional moment. For the studied cases, a poor correlation and unconservative predictions are found. Responses using unidirectional and bidirectional seismic actions are compared, and instant eccentricities on X and Y direction are induced for buildings with static eccentricity only on the X direction. In the second stage, a set of ten seismic events prepared for Los Angeles area is used to evaluate the maximum demands induced in sets of one story and three story buildings. Twelve angles of incidence are used with each seismic event. The demands are calculated for different values of static eccentricity, induced by the location of the center of mass, the location of the static center of rigidity, and the strength asymmetries of frames. |
