Numerical Analysis of Multilevel Eccentric Chevron Braced Frame for Improved Inelastic Behavior

This paper presents a renovation strategy to upgrade the conventionally constructed chevron braced (both concentric and eccentric) steel frames in such a way that each set of the upgraded braces would uniquely display the characteristics of two simultaneously working eccentric braces at each story. The upgraded configuration of the chevron brace is termed here as a multilevel eccentric chevron (MLEC). Nonlinear numerical analysis was conducted to access the inelastic behavior of the braced frames under cyclic loading. The reduced deflection of beams, rectification of the sudden peaks in the hysteresis curves obtained for the initially concentric chevron braced frame, symmetric/balanced hysteresis curves obtained for the initially eccentric chevron braced frame, and the significant improvement in the plastic dissipation by the MLEC braced frames indicated toward the achievement of an excellent seismic behavior. The presented strategy would be very cost-effective, handy (ease of construction), least disruptive, and cause minimal structural intervention. This strategy was found to significantly improve both the strength and ductility of the conventionally constructed chevron braced frames.