Fail‐safe optimization of viscous dampers for seismic retrofitting

Abstract

This paper presents a new optimization approach for designing minimum-cost fail-safe distributions of fluid viscous dampers for seismic retrofitting. Failure is modeled as either complete damage of the dampers or partial degradation of the dampers' properties. In general, this leads to optimization problems with large number of constraints. This may result in high computational costs if all the constraints are simultaneously considered during the optimization analysis. Thus, to reduce the computational effort, the use of a working-set optimization algorithm is proposed in this paper. The main idea is to solve a sequence of relaxed optimization subproblems with a small subset of all constraints. The algorithm terminates once a solution of a subproblem is found that satisfies all the constraints of the problem. The retrofitting cost is minimized with constraints on the interstory drifts at the peripheries of frame structures. The structures considered are subjected to a realistic ensemble of ground motions, and their response is evaluated with time-history analyses. The transient optimization problem is efficiently solved with a gradient-based sequential linear programming algorithm. The gradients of the response functions are calculated with a consistent adjoint sensitivity analysis procedure. Promising results attained for 3-D irregular frames are presented and discussed. The numerical results highlight the fact that the optimized layout and size of the dampers can change significantly even for moderate levels of damage.

Simultaneous analysis and design optimization for seismic retrofitting of hysteretic structures with fluid viscous dampers

“…This is also true in the case of added viscous damping systems. In recent work by the author, a novel approach to fail-safe design optimization of FVDs was proposed for seismic retrofitting applications, (Pollini, 2020). It was shown that it is possible to develop a computationally efficient framework to design optimal fail-safe damper layouts.…”

Seismic performance of the combined viscous-steel damping system suffering from oil leakage

“…The fluid viscous dampers were originally developed for military and aerospace industries (Lee and Taylor, 2001). In 1990s, they were found to be also effective in mitigating civil engineering structural vibration, and then gradually be applied to bridges and buildings (De Domenico et al, 2019; Piollini, 2020). Through the flow of internal high-viscosity fluid, massive kinetic energy can be converted into heat and consumed by the viscous damper (Jiao et al, 2017).…”

Reliability index based strategy for the probability-damage approach in fail-safe design optimization (β-PDFSO)

“…Stolpe [40] modeled failure as either a complete damage of some predefined number of members or by degradation of the member areas, and concluded that the optimal topology can change drastically even in the situation that only one member is partially degraded. Based on this idea, Pollini [37] performed the fail-safe optimization of viscous dampers.…”