Abstract

No abstract

The earthquake performance of stone masonry Post-Byzantine churches subjected to seismic forces is examined. First, a three-nave Basilica is studied with a system of stone-masonry vaults and domes as a superstructure together with a wooden roof. Next, a cruciform type 18th century church is studied which also utilizes a system of cylindrical vaults and spherical domes that form the superstructure together with the wooden roof. In addition, a three-nave 18th century Basilica is examined where the wooden roof is supported directly on the peripheral masonry walls and the internal colonnades. All these churches developed structural damage to the masonry that is believed to arise from the amplitude of the gravitational and seismic actions combined with the deformability of the foundation, which is examined here. It is shown that the foundation deformability explains, partly, the appearance of structural damage. The numerically predicted regions that reach limit state conditions correlate well with actual damage patterns. Moreover, the vaults and domes of the superstructure appear to be vulnerable also.

The seismic performance of "Greek" churches made by low-strength unreinforced masonry is examined. These structures were damaged during recent strong seismic activity in Greece combined with long term effects from foundation settlement. Measurements from shear-sliding laboratory tests of stone masonry triplets are presented and discussed together with corresponding numerical simulation results in an effort to quantify the in-plane sliding shear failure criterion. The cohesive surface interaction constitutive law was employed in forming realistic limit-state criteria for such weak mortar stone masonry. Next, the performance of specific "Greek" churches is numerically simulated employing simplified dynamic linear elastic analysis and assumed limit-state criteria. This simplified approach yielded realistic predictions of the observed performance. However, the necessity to obtain a comprehensive set of measured strength properties for such type of masonry construction is underlined. From this simplified dynamic linear elastic analysis it can be concluded that the soil-foundation deformability results in a significant increase in the tensile stress demands at critical regions. This conclusion is also in agreement with the observed damage.