Investigation of seismic performance of concentrically braced frames with zipper columns

Inverted-v braced frames are typical braced frame configurations which with increase of lateral loads the compressive braces buckle and plastic hinges form in the braces. Shear capacity of frame decrease as a result of compression braces' buckling. To overcome these limitations of chevron braced frames zipper braced frames have been suggested. Zipper columns are vertical members connecting the mid points of the beams above the first floor. In order to investigate the seismic behavior of zipper braced frames 3, 6, 9 and 12 story zipper braced frames was designed and modeled in ABAQUS and nonlinear time history analyses were conducted. As a consequence, the results showed that zipper columns help to improve the seismic performance by uniform damage distribution over the height of building.

Keywords:

chevron brace , nonlinear time history analyses , unbalanced force , zipper strut