Editorial

Abstract

This issue of Structures and Buildings contains the performance evaluation of self-centring steel-braced frame, plastic design of eccentrically braced frames with shear panels, fluid viscous dampers locations in reinforced-concrete core wall buildings, correlation of a new index with energy-based damage indices and seismic progressive collapse of momentresisting frames and eccentrically braced frames (MRF-EBF) dual steel systems. The presented papers continue the tradition of this journal to provide results useful for the professional development of its readers. This issue contains papers that have passed the usual rigorous peer review procedure adopted by the journal and contribute to the areas of knowledge discussed in this Editorial.This first paper presents the performance evaluation of selfcentring steel-braced frames (Rahgozar et al., 2016). A modern self-centring braced frame equipped with post-tensioned cables and replaceable fuses is capable of rocking on its foundation during an earthquake. The aim of this paper is to evaluate the seismic performance of a controlled rocking braced frame and compare its efficiency with a similar fixed-base braced frame. A non-linear time history analysis is conducted for a set of archetypes, varying in height, seismic design category and seismic frame type. A sensitivity analysis is performed to examine the effects of modelling and ground motion parameters. Results indicate that the rocking system is capable of enhancing the performance of a conventional braced frame by features such as the controlled rocking mode, self-centring and concentrated damage to replaceable fuses.The second paper presents the plastic design of eccentrically braced frames with shear panels (Hamed and Mofid, 2016). This paper introduces a new earthquake-resistant building design featuring eccentrically braced frames with steel wall shear panels. It also proposes closed-form expressions for analysis and extension of the existing failure mode control design method for the new structural system. Closed-form equations for internal forces were obtained, and probable failure mechanisms and corresponding lateral load multipliers for secondary effects were identified. Selection of member profiles was completed by the mechanism equilibrium curve concept. Pushover modelling was then performed with plastic hinge distribution corresponding to failure mechanisms. Only small differences were found between the analytical and modelled values of lateral force multipliers, meaning that the closed-form equations are a valid alternative approach for plastic analysis and design of eccentrically braced frames with shear panels.The third paper is about the fluid viscous damper locations in reinforced-concrete core wall buildings (Ahmed, 2016). A flexural plastic hinge is assigned and detailed at the core wall base and coupling beams ends to control seismic responses. This strategy is based on allowing damage to main structural components. To avoid damage to main structural components, an alternative strategy using ene...