ABSTRACT
This paper analyses the inelastic behaviour of eccentrically braced frames by means of pushover and dynamic response analyses. The structural typologies considered include standard eccentrically braced frames and schemes provided with vertical or diagonal elements, which connect the ends of each link to the upper storey (tied or trussed braced frames). The length of the links has been varied so as to examine both short links (which yield for shear) and long links (which yield for bending moment). The number of storeys has been varied from 4 to 12, so as to point out its influence on the behaviour of the scheme. Pushover analyses have shown some differences in the behaviour of schemes with short, intermediate or long links, together with an increase of ultimate displacements when ties or trusses are added, independently of the number of storeys. On the contrary, dynamic analyses have pointed out the strong influence of the number of storeys in the case of standard eccentrically braced frames, which are dramatically penalised by the arising of a soft-storey behaviour. The adoption of ties or trusses is really effective in preventing such behaviour and in granting the eccentrically braced frames a highly dissipative response also in the case of tall buildings.
