Effect of the secondary system stiffness on the HYDE system behaviour

Abstract

The thread of earthquakes has grown in the last decades due to the presence of heavily populated areas. Fortunately the advances in earthquake engineering have resulted in some interesting solutions or systems to prevent both, collapse and structural damage, during the seismic event. Although a small overview of the different existing systems is done at the very beginning, this thesis is focused mainly on the HyDe systems, a type of passive control specially suitable for buildings with soft storeys in which the controlling mechanism relies on the rigid body motion and the stiff-ductile behavior of the hysteretic devices. However, not all the aspects concerning this type of structural control are considered; only the effect of the secondary horizontal loading system (SHS) is studied in depth. To analyze this effect, what has been done is to increase the slenderness ratio (H/B) until the shear deformation form is replaced by the bending deformation. When this happens, it can be said that SHS has the control over the structure instead of the hysteretic devices. Two methods are proposed to design the HyDe system on this document with the main goal to achieve the most effective stiffness: (a) the buckling method based on starting the design at the buckling stiffness, and (b) the rotational spring method that implements a tiny detail at the end of the columns of the first storey. Finally, the simulation of the steel structures, with a HyDe system (shear panel) placed in the soft storey, has been done using the structural software SAP2000 and several EC-8 generated accelerograms to reproduce the seismic event in the program.