No abstract

Purpose It is well known that the real behaviour of joints lies between the ideal pinned or rigid joint responses. Additionally the influence of this behaviour on the global structural response has been widely studied in the past centred on the plastic resistance or the critical load. On the other hand, there are relatively few studies focusing on the dynamical response of these structures. This paper aims to discuss these issues. Design/methodology/approach Two types of structures with rigid and semi-rigid joints were considered. Their inelastic response was evaluated using the N2 conventional pushover method, and were later compared to the results from a full non-linear dynamic analysis. Findings The results indicated that increasing joint flexibility makes the structure less rigid, lengthening its fundamental period and enhancing its horizontal displacement. Furthermore, a parametric study showed that joint flexibility might be of paramount importance to low to medium rise buildings response. Originality/value The evaluation of the influence of joint flexibility on the inelastic behaviour of steel structures located in seismic zone is of paramount importance, and is tackled in this paper.

Purpose The purpose of this paper is to investigate the static and dynamic inelastic response of rigid and semi-rigid connections of steel structures with concrete-filled steel tube (CFST) columns built in high seismic areas, and to compare it with those with open section columns. Design/methodology/approach CFST columns are frequently used in moment resistant steel frames located in seismic areas due to their inherent advantages, including their ductility, energy absorption capacity as well as their high bearing capacity. The smart combination of steel and concrete makes it possible to benefit from the advantages of both components to the maximum. This research work presents the nonlinear dynamic response of moment resistant steel frames with CFST columns, with rigid or semi-rigid connections, built in high seismic areas, according to the Algerian seismic code RPA 99/2003, European EC8 and American FEMA 356 to show the nonlinear characteristics of this type of structures, and their advantages over steel frames with open section columns. Findings The paper presents the advantages of using CFST columns with rigid and semi-rigid connections on the seismic response of portal steel frames. A high performance level in terms of ductility, plastic hinges distribution and their order of appearance has been obtained. It also shows the low effect of seismic loading on the structural elements with CFST columns compared to structures with open section columns. Originality/value The investigation of the numerical results has shown the possibility of their use in the seismic areas for their adequate performance, and also with respect to the design limits specified in the seismic guidelines. In addition, this study represents a first step to develop seismic performance factors for steel structures with CFST columns in Algeria, where the Algerian code do not include a comprehensive specification for the composite steel structures.

Conventional analysis of steel frames assumes either perfectly rigid or pinned connections. The rigidity of most connections behaves, in fact, somewhat between these two extremes. Therefore incorporating the effect of connection flexibility into the analysis and design procedure of the frame becomes necessary.Buckling of a column is fundamental to the design of load bearing structures mainly when the analysis of such frames takes into account the effect of the connection flexibility.The objective of this paper is to present a simplified approach for the evaluation of the elastic buckling load for steel frames with semi-rigid joints. To this end, a simple model that takes into account the effect of beam-to-column joint flexibility in the analysis of steel frames is proposed and a corresponding stiffness matrix element is presented. The model developed has been verified to be valid using an illustrative example found in the literature; numerical results are provided to illustrate the accuracy of the results.