Akademik Veri Yönetim Sistemi
WCEE2024 - 18th World Conference on Earthquake Engineering, Milan, İtalya, 30 Haziran - 05 Temmuz 2024, cilt.1, sa.1, ss.1-9
The title subject is addressed in this report, by making a reference to the 2019 E-Defense test on current-design-base wood dwelling structures. According to the sponsor of Metropolitan Project, the Japan government (MEXT), new insights towards the future society were emphasized. Three-story Post-Beam Structure (PBS) and Shear-Wall Structure (SWS) adopted the same configurations and the Japanese grade-3 design criteria. Given the adopted test protocol, compared are the four cases;(1) PBS with a Base-Isolation (BI), (2) SBS with a generic RC mat foundation on soil and (3) PBS and (4) SWS restrained at the foundations.
The allowable stress design procedure demands different tension forces at the first-story bases of the PBS and SWS. Anchor steel bolts embedded in the foundations are used against the base tension forces, and the numbers of the bolts were 17 in the PBS and 2 in the SWS. Eventually, the SWS showed the tension fracture mode at the first story base. The total bending moment capacity in a certain direction is calculated by accumulating the partial moments derived from the local fracture strengths. The calculated values were consistent to the test results in various directions. In the case of PBS, the overturning moments in the tests kept smaller than the calculated total moment capacities and exhibited higher capacity.
In the entire building system, the foundation sliding occurred at the interface of foundation and soil. Even in sequential inputs of MCE motions, a constant damage state was kept. Once the structural system changes from the upper structure failure mode to the foundation-sliding soil failure mode, the collapse probability becomes very low. Thus, if upper structure and foundation-sliding soil failures are precisely evaluated, the totally different ultimate failure modes can be controlled in practice. In the following tuned PBEE assessment, the upper structure started collapsing before the foundation sliding, when the grade-1 strength (Japanese standard). The grade-3 strength is available with low additional costs to the totally different structural failure mechanism. Research outcomes by systematically testing strategies are contributing not only to the individual building system enhancement but also to the comprehensive PBEE enhancement.