Intervention cost optimization of bracing systems with multiperformance criteria

Abstract

In this paper a multiperformance optimization procedure to design dissipative bracing systems controlling the structural performance while minimizing the intervention cost is proposed. The procedure allows dimensional and topological optimization of bracing, considering inelastic behaviour of braced structures through properly developed visco-elastic equivalent linearization schemes. The structural behaviour is controlled through constraint functions on interstory drift ratio (IDR) while the intervention cost is explicitly encountered by considering real costs that mainly influence it. The procedure is suitable for both new and existing structures, however the objective function is specialized on typical costs of retrofit interventions. A numerical example on a multistory frame has been developed in order to show the effectiveness of the procedure to provide the optimal characteristics and arrangement for the braces, while the suitability of linear equivalent schemes to predict the structural response is investigated through Nonlinear dynamic analyses. Further, a comparison of the estimated intervention costs by asking for different performance levels is performed, showing how the proposed objective function is able to help the designers to identify the ideal performance levels and acceptance criteria to reduce the cost-benefit ratio.

A simplified method to predict torsional effects on asymmetric seismic isolated buildings under bi-directional earthquake components

“…In fact, an inherent simplification of seismic isolation systems relies in the fact that they are usually designed to obtain an elastic or almost elastic behaviour of the structural portion that they intend to protect, with nonlinearities concentrated in the devices, whose behaviour is easier to predict and control. This makes seismic isolation attractive compared to other techniques that often require the nonlinear behaviour assessment of the whole structure (Formisano et al 2008;Dall'Asta et al 2017;Morelli et al 2017;Laguardia et al 2017;Formisano and Massimilla 2018;Braga et al 2019). In general, linear analyses through the use of a proper linearization procedure can be performed, provided that some applicability conditions are met, as requested by the main international codes (CEN 2004;NTC 2008;ASCE 2010;NTC 2018).…”

Risk‐based optimization of concentrically braced tall timber buildings: Derivative free optimization algorithm

“…developed a procedure to minimize intervention cost of retrofitting interventions through viscoelastic device, time‐domain analyses and gradient‐based algorithms. Braga et al 27 . proposed a procedure to minimize intervention costs while constraining interstory drift and using Response Spectrum Analyses (RSAs) on linearized models and gradient‐based algorithms.…”

Mechanical model of steel frames with reinforced concrete infill walls

“…Following the same principles, Steel frames with Reinforced Concrete infill Wall (SRCWs) are an hybrid structural system recently and specifically developed to exploit both the high lateral stiffness of the r.c. wall in the in-plane direction and the potential high dissipative capacity of the steel frames (Morino 1998;Hajjar 2002;Zona et al 2008), aiming therefore at low or null damage for service level limit states and moderate damage for higher action levels (Braga et al 2019). Moreover, they are characterized by an easy repair after moderate damage using epoxy resins on the cracked wall.…”