Effects of brace stiffness on performance of structures with supplemental Maxwell model-based brace-damper systems

Shear-type buildings with Maxwell model-based brace-damper systems are studied in this paper with a primary emphasis on the effects of brace stiffness. A single-story building with a viscous damper installed on top of a Chevron-brace is first investigated. Closed-form solutions are derived for the simple structure, relating the brace stiffness and damper coefficient to the targeted reduction in response displacement or acceleration. For a given brace stiffness, the solution is minimized to give a set of formulae that will allow the optimal damper coefficient to be determined, assuring the desired performance. The model is subsequently extended to multistory buildings with viscous dampers installed on top of Chevron-braces. For a targeted reduction in the mean square of the interstory drift, floor acceleration or base shear force, the minimum brace stiffness and optimal damper coefficients are obtained through an iterative procedure. The response reduction, which signifies the improved performance, is achieved by a combination of brace stiffness and viscous damper coefficients, unlike conventional approaches where damper coefficients are typically optimized independent of brace stiffnesses. Characteristics of multi-degree-of-freedom systems are studied using a 2-story and a 10-story buildings where the effects of brace stiffness on the overall performance of the building can be quantified.