Retrofit of Double Angles in Concentrically Braced Frames


Abstract (Summary)
The following study attempts to find a suitable buckling restraining mechanism that could be easily attached to existing brace members in concentrically braced frame structures to enhance their lateral load resistance. Several sets of double angles representing half-scale braces from a model building were fabricated. Steel pipes were strapped to some of the brace specimens to enhance their buckling strength. The enhanced or retrofitted brace yielded a 36 percent increase in buckling capacity over a bare brace. The laboratory results were scaled to fit the model building, and a series of collapse analyses incorporating different bracing scenarios was conducted. Retrofitting the ground floor in the model building nearly doubled the base shear resistance at the onset of buckling, and a 17 percent increase in the ultimate lateral load. The inter-story drift of the model building remained well within serviceability limits when the ground level braces reached their buckling capacity. Retrofitting the ground level braces allowed the model building to be used in a wider area of the country.
Bibliographical Information:


School:University of Cincinnati

School Location:USA - Ohio

Source Type:Master's Thesis

Keywords:buckling restrained braces double angles seismic design retrofit


Date of Publication:01/01/2008

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