Pinned and Fixed Connections in Six Storied “Inverted Y-braced” Frames

The present paper intends to illustrate the influence of rigid and/or pined beam/column and diagonal/column connections on the seismic behavior of a six story “inverted Y” eccentrically braced frame. The considered “inverted Y” braced frame had two spans of 6.6 m, six story of 3.5 m and was equipped with short dissipative members of 1.2 m (located in vertical elements outside of the frame girders). Four configurations were analyzed for the “inverted Y” braced frame. In the first configuration rigid connections were used for all kind of structural elements. The second configuration had hinged beam/column and diagonal/column connections. In case of the third configuration, rigid connections were used among all kind of structural elements. Compared to configuration one, additional potentially plastic zones with reduced cross-sections (resembling the “dog-bone” detail) were considered along the girders and braces, near the member ends connected to the columns. The fourth configuration had hinged diagonal/column connections and additional potentially plastic zones were considered only along the frame girders, near the girder ends connected to the columns. Dynamic nonlinear analyses were performed with each frame configuration. The distributions of plastic hinges during the nonlinear analyses was observed. The maximum values for different kind of member forces and the extreme inelastic deformations were compared.