RELIABILITY ANALYSIS FOR NON STANDARD MASONRY SYSTEMSUNDER SEISMIC LOADING

摘要

The paper concerns the analysis and experimental characterization of a number of non-standard masonrytypes that are commonly present in Calabria (Italy), a region at a high seismic risk. In order to assess thestructural reliability and to design the retrofitting interventions for such indigenous constructive types it isimportant to know the local techniques and to carry out a specific on-site experimental investigation.The attention has been focused on a number of towns in the district of Cosenza. Here, a survey has beencarried out in order to detect and classify the structural features of the local residential housing. Asignificant element observed was the large presence of buildings made of a non-standard masonry thatdoesn't meet law requirements and mostly dated back to the first half of the XIX century, a period inwhich hollow bricks (usually employed for curtain or enclosure walls) available on the market at a lowcost were diffusely used in substitution/combination of the ancient materials in the construction oftraditional bearing masonry walls.After surveying and classifying the different types (elements, textures, structural configurations...), themasonry elements and the materials have been experimentally investigated (by testing samples taken onsite and manufactured in laboratory), as here specified:Mortars: composition of the mixture; chemical and mechanical properties (tensile and compressivestrength).Hollow clay/concrete blocks: dimensional features; defects; mechanical properties (compressive strengthin the two directions-parallel and perpendicular to the holes).Masonry panels with clay/concrete blocks: uniaxial and diagonal compression tests (compressive andtangential strength).The collected data have been processed and compared with the Italian and European laws, collecting thenecessary information for an assessment of the structural reliability convenient for the local context, anddefining the most suited strategies of rehabilitation/retrofitting for the seismic risk. In fact, for economicaland practical reasons, it is not acceptable a systematic carpet-substitution of the existing residentialhousing. Trough this research work it was possible to collect the necessary information for an assessmentof the structural reliability convenient for the local context, and to define the most suited kind of