Multi-level performance-based design optimisation of steel frames with nonlinear viscous dampers

Abstract

This paper presents a practical multi-level performance-based optimisation method of nonlinear viscous dampers (NVDs) for seismic retrofit of existing substandard steel frames. A Maxwell model is adopted to simulate the behaviour of the combined damper-supporting brace system, with a fractional power-law force–velocity relationship for the NVDs, while a distributed-plasticity fibre-based section approach is used to model the beam-column members thus incorporating the nonlinearity of the parent steel frame in the design process. The optimum height-wise distribution of the damping coefficients of NVDs satisfying given performance requirements is identified via a uniform damage distribution (UDD) design philosophy. The efficiency of the proposed multi-level performance-based design optimisation is illustrated through nonlinear time-history analysis of 3-, 7- and 12-storey steel frames under both artificial and natural spectrum-compatible earthquakes. Sensitivity analysis is performed to investigate the effects of initial height-wise damping distribution, convergence factor and uncertainty in design ground-motion prediction on the optimisation strategy. The efficiency of the final optimum design solution is also investigated by using drift-based, velocity-based, and energy-based UDD approaches to identify the most efficient performance index parameter for optimisation purposes. It is found that regardless of the selected performance parameter, the optimum damping distribution identified by the proposed methodology leads to frames exhibiting lower maximum inter-storey drift, local damage (maximum plastic rotation) and global damage index compared to an equal-cost uniform damping distribution. However, using drift-based UDD approach generally results in a better seismic performance. It is shown that the proposed UDD optimisation method can be efficiently used to satisfy multiple performance objectives at different intensity levels of the earthquake excitation, in line with performance-based design recommendations of current seismic codes. The proposed method is easy to implement for practical design purposes and represents a simple yet efficient tool for optimum seismic retrofit of steel frames with NVDs.

Seismic Design of Bolted Connections in Steel Structures—A Critical Assessment of Practice and Research

“…Velocity-dependent viscous dampers have been widely employed for seismic retrofitting of existing substandard steel frames due to their advantageous capability of providing supplemental energy dissipation without significantly altering the stiffness properties of the structure. Optimization procedures of viscous dampers for applications to substandard braced steel frames were comprehensively discussed by Del Gobbo et al [172] and by De Domenico and Hajirasouliha [173] with reference to linear and nonlinear fluid viscous dampers, respectively.…”

Cross-story installation of viscous dampers in timber frame houses for earthquake damage reduction

“…Furthermore, viscous dampers have been used for seismic enhancement and retrofitting (Uriz and Whittaker, 2001;Martinez-Rodrigo and Romero, 2003;Sorace and Terenzi, 2009;Rama Raju et al, 2014;Lavan, 2015;Pollini et al, 2016Pollini et al, , 2017Impollonia and Palmeri, 2018;Aydin et al, 2019;Tabar et al, 2021). Design procedures and optimum design methods have been studied for use of supplemental dampers in structures (Tsuji and Nakamura T, 1996;Uetani et al, 2003;Lavan and Levy, 2005;Lavan and Levy, 2006;Silvestri and Trombetti, 2007;Hwang et al, 2008;Takewaki, 2009;Hao and Zhang, 2016;Kawamoto et al, 2016;Parcianello et al, 2017;Wang and Mahin, 2018;Idels and Lavan, 2020;De Domenico and Hajirasouliha, 2021;Wani et al, 2022). While previous studies have investigated high-rise buildings, slender towers, and long-span bridges that may suffer severe damage due to seismic excitations or wind loads, no research had been conducted on low-story houses until small-size viscous dampers were developed and applied to housing structures.…”

Effectiveness and robustness of braced‐damper systems with adaptive negative stiffness devices in yielding structures

“…[45][46][47][48] Hence, investigations on braced-damper systems were further extended to inelastic structures concerning the performance and optimization design. [49][50][51][52][53] In terms of negative stiffness devices, although the majority of the relevant literatures aimed at elastic structures, some pioneers still made great efforts in the application of negative stiffness devices for yielding structures. Nagarajaiah et al [25][26][27][28][29][30] proposed and tested an adaptive negative stiffness device, which was able to develop positive stiffness from negative stiffness adaptively and passively at large deformation; thus in turn limits the damage level (inelastic deformation) of the main structure.…”

“…During their long‐term servicing periods, civil engineering structures are very likely to encounter excessive earthquakes beyond their designed intensities, where yielding or inelastic deformation becomes an inevitable issue for practical structures unless their designs are very conservative 45–48 . Hence, investigations on braced‐damper systems were further extended to inelastic structures concerning the performance and optimization design 49–53 . In terms of negative stiffness devices, although the majority of the relevant literatures aimed at elastic structures, some pioneers still made great efforts in the application of negative stiffness devices for yielding structures.…”