Development of new fully restrained bolted bracket moment connections for strong joints

Recently, the Double Shear Bolted Brackets (DSBB) moment connection with four-bolt configuration has been introduced as a new fully restrained moment connection for use in shallow beam-column joints. With regards to deep beam connections, it is a requirement to have stiffer and stronger connections in the DSBB connection group. Knowing that similar code-qualified bolted bracket connections, Kaiser Bolted Bracket (KBB) connections, have marginal rotational stiffness, they cannot be considered as a fully restraint moment connection in deep beam-to-column joints. Therefore, in this discourse, six-bolt and eight-bolt configurations of DSBB are developed and their design methodology is outlined. Less thickness of bracket components, less diameter of bolts used, and greater stiffness compared to KBB code-qualified (AISC 358-16 standard) connections by the (KBB connection) are the main advantages of these new connections, making them a more applicable option of fully restrained connections for deep beam joints than their counterpart KBB connection. First, the DSBB design method is developed considering all possible limit states of buckling, yield, and rupture failures for the plate components of each bracket. Then, by using a validated high fidelity finite element study, the cyclic performance of DSBB connections is obtained and successfully accepted based on the AISC 341-16 standard requirements for fully restrained connections in special moment connections. The results indicated the low risk of failure and proper relaxed stress distribution around the connection compared to the corresponding KBB connection. In addition, the material consumption of DSBB six-bolt and eight-bolts were 19.7% and 6.9% in bolts and were 19.9% and 42.9% in brackets less than that of the corresponding KBB connections. Finally, it is concluded that DSBB six-bolt and eight-bolt configurations are efficient choices of fully restrained moment connections for application in deep beam-column joints.