PHYSICAL AND VIRTUAL EXPERIMENTAL INVESTIGATION OF SELF-CENTRING CONCENTRICALLY BRACED FRAMES

Abstract

The self-centring concentrically braced frames (SC-CBF) present an innovative structural typology for improved behaviour of the steel structures to earthquake loading. Namely, the SC-CBFs present an advanced technological solution for minimization of the residual drifts at concentrically braced frames which are quite substantial following high intensity seismic action. This structural type’s main characteristic is the re-centring of the frame following the earthquake loading in the initial vertical position, thus reducing the post-earthquake cost and time for retrofitting. It also reduces the material used for repair since the only elements needing retrofitting remain the diagonal braces that undergo many cyclic loadings under the earthquake excitation and develop plastic hinges. However, in order to validate this behaviour, many experimental investigations are required. For that purpose, this study addresses previous, current and future experimental testing considerations and shows the results and potential findings. Firstly, the previous experimental studies involving quasi-static and shake table testing are presented. Then, a virtual experimental procedure is presented in order to tackle the most demanding aspects of calibration and parameter estimation for the simulation of dynamic structural response. The various types of experimental procedures are then combined in order to form a complete methodology for estimation of the main characteristics of the novel system and proceeding to a code conforming evaluation procedure. A combination of these experimental methodologies is the ultimate method for developing reliable numerical simulation model, as well. The calibrated model is subjected to reliability analysis in order to estimate the probability of failure for predefined failure scenarios. Finally, the numerical model is used for developing several archetype structures and thorough parametric study for EC conform design procedure.