A Simple Evaluation Method of Seismic Resistance of Residential House under Two Consecutive Severe Ground Motions with Intensity 7

A sequence of two strike-slip earthquakes occurred on April 14 and 16, 2016 in the intraplate region of Kyushu Island, Japan, apart from subduction zones, and caused significant damage and disruption to the Kumamoto region. The analyses of regional seismic catalog and available strong motion recordings reveal striking characteristics of the events, such as migrating seismicity, earthquake surface rupture, and major foreshock-mainshock earthquake sequences. To gain valuable lessons from the events, a UK Earthquake Engineering Field Investigation Team (EEFIT) was dispatched to Kumamoto, and earthquake damage surveys were conducted to relate observed earthquake characteristics to building and infrastructure damage caused by the earthquakes. The lessons learnt from the reconnaissance mission have important implications on current seismic design practice regarding the required seismic resistance of structures under multiple shocks and the seismic design of infrastructure subject to large ground deformation. The observations also highlight the consequences of cascading geological hazards on community resilience. To share the gathered damage data widely, geo-tagged photos are organized using Google Earth and the kmz file is made publicly available.

Section: Strong Motion Characteristics In the Near-fault Regionmentioning

confidence: 99%

The 2016 Kumamoto Earthquakes: Cascading Geological Hazards and Compounding Risks

Goda

Campbell

Hulme

et al. 2016

“…During this earthquake, unprecedented large-amplitude ground motions (over 2.0m/s velocity amplitude compared to 0.5m/s for severe earthquake ground motions for tall buildings in Japan), called long-period pulse-type ground motions, were recorded. Since such large-amplitude ground motion is a serious event, the suppression of plastic deformations is strongly desired in view of the resistance and recovery from the viewpoint of earthquake resilience (Kojima and Takewaki, 2016;Ogawa et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Hysteretic-Viscous Hybrid Damper System With Stopper Mechanism for Tall Buildings Under Earthquake Ground Motions of Extremely Large Amplitude

Hashizume

Takewaki

2020

Self Cite

This paper is aimed at proposing a hysteretic-viscous hybrid (HVH) damper system for tall buildings subjected to long-period pulse-type earthquake ground motions of extremely large amplitudes. The HVH system was introduced for a single-degreeof-freedom (SDOF) system in the recent paper (Hashizume and Takewaki, 2020). The HVH system consists of a large-stroke viscous damper and a hysteretic damper with a gap mechanism as a stopper for mitigating catastrophic damage. In the present paper, the effectiveness of the HVH system is shown for tall buildings. Pulse-type earthquake ground motions of an extremely large amplitude have been recorded in the past (for example Northridge 1994 and Kumamoto 2016). These ground motions risk causing catastrophic damage to high-rise and base-isolated buildings with a long natural period. A double impulse is used here as a substitute for pulse-type ground motions of an extremely large amplitude. Time-history response analyses are performed for an amplitude-modulated critical double impulse to reveal the effectiveness of the proposed HVH system. In addition, double impulse pushover (DIP) analysis, which was proposed by Akehashi and Takewaki (2019), is conducted to reveal the critical resonant performance of elastic-plastic tall buildings together with the analysis for recorded ground motion at Kumamoto (2016). A comparison with the dual hysteretic damper (DHD) system composed of parallel-type small-and large-amplitude hysteretic dampers is also conducted to investigate the seismic performance of the proposed HVH system.

“…As a result, unprecedented large-amplitude ground motions, called long-period pulse-type ground motions, were recorded. Even for such large-amplitude ground motions, the suppression of plastic deformations is strongly recommended in view of the resistance and recovery as the measure of earthquake resilience (Kojima and Takewaki, 2016;Ogawa et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Hysteretic–Viscous Hybrid Damper System for Long-Period Pulse-Type Earthquake Ground Motions of Large Amplitude

Hashizume

Takewaki

2020

Self Cite

This paper aims to develop a hysteretic-viscous hybrid (HVH) damper system for long-period pulse-type earthquake ground motions of large amplitude. Long-period pulse-type earthquake ground motions of large amplitude have been recorded recently (Northridge, 1994; Kumamoto, 2016). It is well-known that these ground motions could cause severe damage to high-rise and base-isolated buildings with long natural period. To mitigate the damage caused by such ground motion, a new viscous-hysteretic hybrid damper system is proposed here, which consists of a viscous damper with large stroke and a hysteretic damper including a gap mechanism. A double impulse is employed as a representative of long-period pulse-type earthquake ground motions of large amplitude and a closed-form maximum response to this double impulse is derived for an elastic-plastic SDOF system including the proposed HVH system. To reveal the effectiveness of the proposed HVH system, time-history response analyses are performed for an amplitude modulated double impulse and a recorded ground motion at Kumamoto (2016). The performance comparison with the previous dual hysteretic damper (DHD) system consisting of small-amplitude and large-amplitude hysteretic dampers in parallel is also conducted to investigate the effectiveness of the proposed HVH system.