Numerical model for the non-linear dynamic analysis of multi-storey structures with semi-rigid joints with specific reference to the Algerian code

Abstract

The current paper aims at investigating the dynamic response of rigid and semi-rigid connections of steel structures built in high seismic areas. A nonlinear dynamic analysis model, which is an extension to the simplified and direct mechanical model used in the static analysis, is proposed and discussed. The novelty of the model consists in the introduction of a bar element with semi-rigid joint as a single element without the need to discretise it (i.e. without a finite element mesh) in the program where non-linearity is considered in the flexibility factor of the stiffness matrix. The model developed is validated through application to examples of steel frames with different types of connections under dynamic forces. The results obtained were very satisfactory. This work is motivated by the need for the revision of the Algerian seismic code (RPA99v2003) which does not yet consider provisions for the design of structures with semi-rigid joints. Based on the results of the study carried out on a multi-storey structure with different types of joints subjected to seismic loading, it can be seen that the safety justifications recommended by Algerian regulations RPA99 in terms of relative displacements as well as the dimension of the seismic joint prove to be too conservative compared to those by Eurocode 8.