Background

Competition motivation

The use of sensors to measure the response of buildings during earthquakes is increasing in popularity. One major application of data obtained from such sensors is to calibrate structural models to better predict the building's behaviour in future events.

In December 2019, a shake-table test of a 3-story reinforced concrete frame building was performed at the E-Defense testing facility in Hyogo, Japan, as part of the Tokyo Metropolitan Resilience Project (Subgroup C, Theme II). This building had concrete wall cladding elements casted to be monolithic with frame elements, with special detailing provided to ensure a desirable deformation mechanism. The building was instrumented with numerous acceleration sensors on all floors. The building was subjected to multiple strong motion events, of which only a few were considered in Round 1 of the Blind Prediction Competition.

Given the uncommon detailing used in the structure and the available acceleration recordings, this is a perfect opportunity to test if recalibration of structural models using such data could lead to more accurate predictions of building response in future events.

The Tokyo Metropolitan Resilience Project and Subproject C Theme II

The Tokyo Metropolitan area in Japan is home to over 35 million people and is a major global economic center. However, it is also located in a highly seismically active region. The socioeconomic impacts resulting from a major earthquake striking the region could be significant. In an effort to reduce such effects in future events, the "Tokyo Metropolitan Resilience Project" was established by the National Institute of Earth Science and Disaster Resilience (NIED). The project comprises of three subprojects as follows:

Subgroup A (social sciences) - enhancing response capability;
Subgroup B (natural sciences) - enhancing ground motion predictive capability;
Subgroup C (engineering) - enhancing disaster preparedness.

There are five themes within Subproject C investigating the performance of buildings of varying structural materials (i.e. timber, concrete, steel), response of non-structural elements, and structural health monitoring techniques. This particular competition falls under Theme II: "Rapid Evaluation of Safety Level of Disaster Resilience Hub Buildings and Rapid Determination of Feasibility of Ongoing Usage".

One of the major motivations behind Subproject C Theme II was to address the poor performance of buildings which were intended to serve post-disaster functions, such as disaster management centers or temporary shelters, in recent seismic events. New stringent performance objectives had been proposed to ensure more adequate performance of such buildings, and the monolithic cladding-frame detailing described previously was hypothesized to be a possible solution. This E-Defense test was thus performed to evaluate if the designed building was capable of satisfying the new design objectives. Furthermore, acceleration sensors were installed to evaluate the reliability of a recently proposed rapid safety evaluation methodology.

Five major shaking excitations were applied using the same artificial record (equivalent to the Japanese Building Standard Law design spectra) but with varying scale factors as follows:

Test 1 - 0.2-scaled

Test 2 - 1.0-scaled

Test 3 - 1.5-scaled (run 1)

Test 4 - 1.5-scaled (run 2)

Test 5 - 1.6-scaled

Differences between Round 1 and Round 2 of the Blind Prediction Competition

The motivation of hosting Round 1 of the Blind Prediction Competition was to observe if participants could predict the performance of a building with uncommon features using traditional structural analysis methods and assumptions. Participants were tasked with predicting the response of the test specimen under Tests #2 and #3. Note that Test #1 was only a small event to evaluate serviceability-level behaviour and was thus not included in the competition.

In Round 2, the motivation is to observe if participants could use response data to better calibrate models for predicting the behaviour of the building in future events. This time, we will provide participants with the total floor acceleration results from Tests #2 and #3, and participants will be tasked with predicting the test specimen's response in Tests #4 and #5.

Additional Information

Further information on the project can be found below:

In addition, the following reference contain more information on the test program:

Yeow TZ, Kusunoki K, Nakamura I, Hibino Y, Ohkubo T, Seike T, Yagi S, Mukai T, Calvi P, Moustafa M and Fukai S. (2020). The 2019 Tokyo Metropolitan Resilience Project E-Defense test of a 3-story disaster management center. Proceedings of the 17th World Conference on Earthquake Engineering, Sendai, Japan.

Source: Matsuda T, Yamao T, et al. 2016. "2016 Kumamoto earthquake emergency disaster report - part 2 (in Japanese). The Japan Society of Civil Engineers (West Chapter)

Source: Nishiyama I, Okawa I, Fukuyama H and Okuda Y. 2011. "Building damage by the 2011 off the Pacific Coast of Tohoku earthquake and coping activities by NILIM and BRI collaborated with the administration." Joint Meeting of U Japan Panel on Win and Seismic Effects, Tsukuba, Japan.

Examples of damaged buildings with intended post-disaster functionality following recent earthquakes in Japan