40,859 research outputs found
Strength and stiffness reduction factors for infilled frames with openings
No full textFramed structures are usually infilled with masonry walls. These may cause significant increase in both stiffness and strength, reducing the deformation demand and increasing the energy dissipation capacity of the system. On the other hand, irregular arrangements of the masonry panels may lead to the concentration of damage in some regions, with negative effects, like for example soft storey mechanisms and shear failures in short columns. Therefore, the presence of infill walls should not be neglected, especially in regions of moderate and high seismicity. To this aim, simple models are available for solid infills walls, such as the diagonal no-tension strut model, while infilled frames with openings have not been investigated adequately. In the present study the effect of openings on strength and stiffness of infilled frames is studied by means of about 150 experimental and numerical tests. The main parameters involved are identified and a simple model to take into account the openings in the infills is developed and compared with other models proposed by different researchers. The model, which is based on the use of strength and stiffness reduction factors, takes into account the opening dimensions and presence of reinforcing elements around the opening. An example of application of the proposed reduction factors is also presented
Experimental investigation of energy damping in masonry mechanisms
No full textSevere earthquakes throughout the world show that existing masonry buildings are prone to suffer out-of-plane local-collapse mechanisms. In such mechanisms energy dissipation is mainly due to impacts against the remainder of the structure. Using data from an experimental campaign on free-rocking walls, estimation are suggested for the coefficient of restitution in both two-sided (façade resting on a foundation) and one-sided (façade adjacent to transverse walls) rocking. Both brick and tuff elements are considered, and the relevance of test repetition and wall height-to-thickness ratio is addressed
Comportamento degli edifici in cemento armato ed in muratura e dei ponti in occasione del terremoto del Cile del 27 febbraio 2010
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