Spectral Functions of Damage Index (DI) for Masonry Buildings with Flexible Floors

Abstract

Most of the buildings in old city cores of Croatia, built between 1860 and 1920 with wooden floors, are mainly designed to bear vertical loads. In this paper we propose a methodology for seismic vulnerability assessment of unreinforced masonry buildings with flexible floors. The methodology is based on the calculation of Damage Index (DI), a numerical value indicating the level of structural damage. In this methodology, the structure is represented using an SDOF model determined by damping, weight, elastic base shear capacity, elastic stiffness and post-elastic stiffness. Using accelerograms of earthquakes, step by step time-history numerical integrations are provided along with the results: top displacement, yield excursions, cumulative energy and base shear-displacement. These results serve as parameters which are then input in the formula for Damage Index (DI). The results of the paper are presented in the form of diagrams with DI values on the y axis and fundamental period of the structure on the x axis. These spectral functions of DI, along with knowledge of fundamental period and chosen accelerogram, can be used to quickly determine the level of damage for unreinforced masonry buildings with flexible floors.

Physics-Based Ground Motion Simulations for the Prediction of the Seismic Vulnerability of Masonry Building Compounds in Mirandola (Italy)

“…Subsequently, the vulnerability indexes have been associated with the estimated damage index, DI, and then correlated to the damage thresholds provided by the European Macroseismic Scale, EMS-98 [52,53], as in Table 3. First, the achieved results presented in Figure 9a have shown that the worst-case scenario is attained for the direction X + (uniform), which corresponds to a C/D ratio equal to 0.67.…”

“…Subsequently, the vulnerability indexes have been associated with the estimated damage index, DI, and then correlated to the damage thresholds provided by the European Macroseismic Scale, EMS-98 [52,53], as reported in Table 3. In Figure 10, the validation between the real damages detected after the Emilia-Romagna earthquake and the corresponding ones derived from the mechanical analysis procedure evaluated at the ultimate displacement, du, referring to the ULS (ultimate limit state) combination, has been provided.…”

Locating Hidden Elements in Walls of Cultural Heritage Buildings by Using Infrared Thermography

“…Vulnerability assessments of the cultural heritage located in seismic areas has been actively researched [1,2]. In the papers by [1,2], the authors proposed a nondestructive and relatively fast but accurate seismic vulnerability assessment of heritage buildings in Tvrđa, the old core of Osijek city. However, performing a detailed analytical design can be of great significance in order to validate this fast seismic vulnerability method.…”