The seismic shear provisions of EC8 for ductile reinforced concrete walls, serving as the lateral load resisting system in multistorey building structures are re-examined. Two aspects are considered: (1) single walls, or a system comprising a number of equallength walls, (2) a resisting system comprising walls of different lengths. It is demonstrated, in light of recent parametric studies, that the EC8 provisions for walls in the medium-and high-ductility classes (DC-M and DC-H, respectively) are both in need of revision. Possible revisions of requirements and a design procedure for a wall system are presented.
An approximate yet accurate formula is proposed for the natural frequencies of coupled shear walls under continuous medium assumptions. First the deflected shape of the structure is represented as the sum of two components: one due to flexural cantilever action and one due to shear-flexure cantilever action. The natural frequencies of the latter two systems are then combined in Dunkerley's formula to yield the approximate frequency of the structure. t Presently on leave at
SUMMARYThis paper is concerned with the design of steel frames using friction damped slotted bolted connections (SBCs) in the diagonal braces. A dynamic model is developed to describe the behaviour of a single-degree-offreedom (SDOF) steel frame that uses bilinear hysteretic behaviour for the damper. This model is generalized to MDOF systems. A novel algorithm for displacement reversal in the transition from slip to stick is presented. It uses numerical noise for its success. A design procedure that attains the sti!ness of the individual braces and their elongation at the threshold of activation is then applied to a 10-storey steel frame. This design process is a two-phase iterative procedure that converges quite fast.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.