Experimental Study of Full-Scale Buckling Restrained Brace With Inspection Windows

The buckling restrained brace (BRB) has been worldwide accepted as a powerful tool to protect structures from earthquake damage. However, the steel core of the traditional BRB is enclosed by the buckling-restraining unit, it is therefore impossible to observe the condition of the steel core during manufacturing and after earthquakes. Presented in this paper is experimental study on a full-scale buckling restrained brace with inspection windows that allow directly observing the condition of the internal components of the BRB, especially for the steel core. Experimental study in deciding the sizes and locations of the inspection windows to inspect the condition of the steel core during testing without influencing the functionality of the full-scale BRB has been conducted to search for a feasible BRB that is economical and convenient for manufacturing and installation as well as meets testing protocols. Test results of the full-scale BRBs under cyclic loadings showed that the mechanical behavior of the full-scale BRB with inspection windows opened on the buckling-restraining unit was stable and that fracture always occurred at the energy dissipation segments after low cycle fatigue tests. The condition of the steel core can be clearly observed through the inspection windows without dismantling the device during the tests. The test results also indicate that the selected inspection windows on the full-scale BRB have little influence on the strength of the device and that an appropriately designed BRB device with inspection windows can be considered as a stable energy dissipation device. A good indicator to decide the necessity of replacement of the BRB device to prepare for next earthquakes has also been proposed in this study.