Composite structures are widely used in building construction in seismic areas whereas hybrid solutions are less diffused and require further investigation. Contrary to commonly used composite structures, in which the deformation demands for steel and concrete components are in the same range (concrete and steel act as one member), hybrid structures allow for a more efficient design of concrete and of steel components with deformation demands tailored to the capacity of the materials. The proposal aims to define innovative steelreinforced concrete hybrid systems for the construction of feasible and easy repairable earthquake-proof buildings exploiting the best properties of both steel and concrete construction techniques by combining them in the most efficient way possible. Hybrid coupled shear walls (HCSW) and steel frames with reinforced concrete infill walls (SRCW) will be considered. In the case of HCSWs, efficient solutions will be defined with reference to the global and local behaviour of the structure. Design procedures will be developed in order to optimise the stiffness ratios between the components so that the contemporary formation of dissipative zones along the building height is guaranteed. Suitable over-strength connection systems will be also defined. Two sets of 4 sub-structures involving the steel link beam, the connection with the r.c. wall and a portion of the r.c. wall, will be realized and tested under cyclic loadings to fully characterize their behaviour under seismic actions and to define realistic models for the global structural analysis. In the case of SRCWs, solutions aimed at obtaining an adequate post-elastic behaviour under seismic actions will be defined. A design procedure capable of furnishing stiffness ratios between components, strength and ductility demand of dissipative zones will be developed. Suitable over-strength connection systems between boundary side steel elements and r.c. infill shear panels will be also defined. Three specimens of the shear connection will be tested under monotonic loads; four specimens of side steel element will be tested under cyclic loadings and, finally, one downscaled specimen of two-storey SRCW will be tested to fully characterize the behaviour of the system under seismic actions. Experimental based realistic models to be applied in the global structural analysis will be developed. The efficiency of the proposed design provisions will be evaluated by means of nonlinear static and dynamic analyses, considering different number of storeys and different geometries of the coupled system to furnish a wide overview of situations of interest in European seismic prone areas. The ductility demands at storeys and their compatibility with connection ductility will be analyzed in both cases in order to establish the global ductility of the structural systems. The two innovative solutions and the relevant design procedures will be applied to a case study by developing two complete designs of all structural and non-structural elements (constructive details). The related construction sequences and an estimation of the costs of construction and maintenance will be defined. The results of this phase and the whole design procedure will be presented in a manual of practice.
Coordinator: University of Camerino, IT
Start Date/Data inizio: 1st July, 2010 – Data fine / End Date: 30th June, 2013