Seismic behaviour of ten storeyed concentrically braced frames

Abstract

The present paper is intended to illustrate the main advantages and disadvantages of four different ten storeyed concentrically braced frames designed under severe seismic actions. All structural members (braces, beams and columns) had built up I-shaped cross-sections, sized according to the provisions of P100-1/2013 and SR EN 1993-1-1. Each of the four considered braced frames were subjected to nonlinear dynamic analyses, using three base excitations (from the 1977-, 1986- and 1990-Vrancea earthquakes), recorded at the INCERC Institute in Bucharest, calibrated all to a peak ground acceleration value of about 0.3 times the acceleration of gravity. Rayleigh damping was taken into consideration. The maximum values of inelastic deformations, bending moments and axial forces in various structural elements, the amount of energy dissipated through plastic deformations and the estimated steel consumption were compared. The extreme values of base shear forces and horizontal displacements were observed. The successive formation of plastic hinges in the different braced frames was analysed.