Seismic Performance Evaluation of a New Type of Reduced Length Buckling Restrained Brace (RLBRB) with S-shaped Core

The use of steel braces in buildings with a moment resisting frame system can significantly control the lateral displacement of the structures. One of the problems with the conventional bracing system is their buckling in compressive loads which reduces the amount of energy absorption of the structure. The buckling restrained braces (BRBs) have been proposed by the removing the buckling at the pressure of common bracing, but overweight, high prices and rigorous implementations have led to the introduction of a new type of buckling brace called Reduced Length Buckling Restrained Brace (RLBRB). However, in RLBRB, due to the low cyclic fatigue phenomenon, the length of bracing can‍‍‍‍‍ not be over-reduced so that it can be replaced as an inactive system after an earthquake. In this research, a new and innovative idea called Reduced Length Buckling Restrained Brace with S-shaped Core is introduced, which, despite its very short length, can overcome all the problems with the RLBRB and BRB system. Therefore, we first validate the analytical models of RLBRB and BRBs in the ABAQUS finite element software based on the experimental results of previous experimental research program. Then, according to the results of the analysis, the hysteresis response of the buckling braces with the S-shaped core is compared with the RLBRB and BRB braces. The results from the comparison of the proposed pattern with conventional buckling braces indicate that, despite the smaller and lighter ones, proposed braces have the same behavior as the BRB braces.