Feasibility study to improve the life of buckling restrained braces and fragility curve analysis for a steel frame with buckling restrained braces

Improving the performance of buckling restraint braces and having uniformity in their performance in a particular structural system can further improve the life of a system. In order to achieve this, demand of the buckling restraint braces needs to be altered by altering their size and effect of changing on structural response needs to be studied in detail. The paper aims at evaluating the feasibility of changing the size of the buckling restrained brace as being a method to increase the overall performance of the system. The paper uses a software PERFORM 3D for modeling and simulating the structure is first subjected to ground motion histories from the Kobe and Northridge earthquakes. Nonlinear time history analysis is then performed on the structure. Fragility curves were then developed to further confirm the improved performance of the system. The structure was subjected to one hundred earthquakes. Peak ground acceleration values for each of the hundred simulations varied from 0.1 to 1 with an increase of 0.1. The results showed that increasing the size of the buckling restrained braces only altered the structural response parameter like interstory drift, displacement, velocity, moment rotations by a small margin and hence it can be used as a method to improve the buckling restrained brace performance. The fragility curves further confirmed the improved performance of the buildings using buckling restrained braces.