## 1 Introduction
In [PERSON] and [PERSON] (2002) [19], this distribution was assumed to be proportional to the stiffness and strength of the columns of each floor. A similar approach was proposed by [PERSON] et al. [20,21] for the storey-distribution of the damping force, derived from the interpretation of the bracing system through its equivalent elasto-plastic SDOF substitute structure. In [PERSON] et al. (2009) [22], an alternative distribution criterion was aimed at regularizing the fundamental mode shape of the braced structure. Unlike previous methods, in [PERSON] and [PERSON] (2004) [23] the variation of the axial load in columns due to seismic inertia loads was taken into account as well. [PERSON] and [PERSON] (2010) [24] proposed an iterative design procedure based on energy criteria for retrofitting RC structures using diagonal braces implementing dissipative shear connections. Figure 1: Examples of old industrial buildings with masonry infills and glazed curtain walls: typical (**a**) outside and (**b**) inside views. According to the Italian Building Code \"NTC-2018\" [25; 26], the dynamic response of steel or RC frames including dissipative braces can be predicted through two different calculation methods: (1) \"Method-A\", which is based on the theory of ductility for nonlinear systems [27] and the use of a behaviour factor to quantify the deformation demand [28; 29]; and (2) \"Method-B\", using the Displacement-Based Design (DBD) procedures originally developed by [PERSON] et al. in 2007 [PERSON] et al. (2007), which is based on the definition of the effective (or secant) stiffness and the equivalent viscous damping of the braced frame [31; 32]. Both design procedures are usually employed by practitioners to achieve the structural safety target under the design ULS seismic scenario. Within this framework, two refinements to tailor Method-B to the presence of typical drift-sensitive elements of warehouse-like buildings, i.e., masonry infills and glazed curtain walls, are proposed. The first refinement, described in Section 2, consists in the definition of two targets expressed in terms of maximum allowable inter-storey displacements. Indeed, despite these buildings featuring only a single storey, the upper windowed band introduces a discontinuity in the perimetral walls that makes it more convenient to distribute the hysteretic braces (i.e., dampers) on two different levels. Although not strictly required for strong ULS earthquakes, these two targets are conceived to ensure (1) the integrity of upper glazed curtain walls and (2) an acceptable level of damage of the masonry infills. The two different performance levels (i.e., acceptable damage vs. full integrity) are justified by the fact that, to the best of our knowledge, the average unit price (i.e., per square meter) of glazed windows is three times higher than that of masonry walls. To ensure the attainment of these performance targets a precise prediction of maximum seismic displacements is fundamental, and requires the employment of accurate formulations for the estimation of the equivalent viscous damping developed by the hysteretic braces (i.e., dampers). In this regard, concerns arise as to the suitability of the formula provided by the NTC-2018 [25] based on the pioneering study by [PERSON] (1930) [PERSON] (1930). As argued below in Section 3, the second refinement provides the adoption of a more recent and reliable formulation already available in the literature. In Sections 4-7, the proposed design method, hereafter called \"Method-B1\", is applied to the design of the strengthening intervention of a case study sport hall located in northern Italy. In Section 8, NLTH analyses on the braced frame are carried out to (1) assess its accuracy in the prediction of the maximum lateral displacement at roof-level and (2) verify the achievement of the two aforementioned design targets.