Shake-table tests of innovative drift sensitive nonstructural elements in a low-damage structural system

摘要

Post-earthquake damage reports have continuously highlighted the significant vulnerability of nonstructural elements to seismic events. Nonstructural damage has severe impact in the building recovery, increasing the socioeconomic losses even for low intensity events. In the last few years, research efforts have focused on the development of innovative nonstructural solutions, to be combined with damage-resistant structural skeletons in order to obtain an overall high-performance building. As part of a European Union (EU)-funded project, the effectiveness of such integrated skeleton&envelope low-damage system in reducing the earthquake related losses was investigated. Tridimensional shake table tests on a 1:2 scaled timber-concrete low-damage structural skeleton, "dressed" by different innovative nonstructural elements (glass/concrete facades, gypsum/masonry partitions), were performed at the National Laboratory for Civil Engineering (LNEC) in Lisbon, Portugal. The shake table tests were carried out at increasing seismic intensities to investigate the structural and nonstructural performance up to a higher-than Collapse Prevention Limit State according to the Italian Code (975 years return period). This paper focuses on the dynamic behavior of nonstructural elements with detailed discussion on construction detailing, seismic demand and performance of the innovative solutions. The high performance of nonstructural elements proved the potential of the details introduced in the partitions/facades. Minimal or no damage was observed up to the end of the overall testing sequence, which reached moderate-to-high interstory drift ratios (more than 1.00%) - typically expected to cause severe damage to traditional nonstructural partitions/infills/facades.