Researchers collaborate on testing seismic resiliency on world's largest shake table

Wood structures remain a staple of modern infrastructure, but for many the fear of an earthquake striking and destroying their home and sense of security is all too prevalent. Earlier this year, the Gulf of Alaska earthquake caused widespread fear along the coast. Researchers at Texas A&M University, in partnership with researchers in Japan, are investigating the resiliency of wood structures to create more reliable and robust infrastructure to withstand extensive damage from strong earthquakes. 

Dr. Maria Koliou, an assistant professor in the Zachry Department of Civil Engineering, will serve as the principal investigator for a National Science Foundation-funded RAPID project, along with six other collaborators and co-principal investigators across the U.S. The team will be traveling early next year to carry out a series of tests on the seismic resilience of wood-framed structures on the largest earthquake defense (E-defense) shake table in the world in Miki City, Japan.

“In our role, this is a RAPID project, so the nature of the project is to collect time-sensitive data and plan potential payload tests for these wood buildings in collaboration with our Japanese colleagues,” said Koliou. “The ultimate goal is to use the knowledge from these tests to establish a holistic framework to evaluate the performance and recovery of wood residential buildings.”

This project is the first among the Japan-U.S. Network Opportunity mutual agreement, which was established over a five year period for the fostering of U.S. and Japanese collaborative research. The project will be the first of its kind to simulate and construct two full-scale houses with utility lines, soil conditions (under one of the houses) and pipelines. The testing will consist of different levels of simulated earthquake intensities on the E-defense shake table and a series of structural retrofits on the houses throughout the experiment.

“One part of our work will be to collect damage and restoration repair data using different levels of seismic intensity until a structure collapse occurs,” says Koliou. "The plan of the Japanese research team is to test both structures to collapse."

The Japanese team will be administering the construction of the houses and leading the tests with Koliou and her team, helping collect time-sensitive data of the damage and repair process using advanced monitoring equipment. Koliou and her group will be using state-of-the-art advanced monitoring equipment to capture the damage and the repair restoration process for the structures. With this data, they hope to create more reliable infrastructure that can not only withstand damage from earthquakes, but will be conducive to building recovery and reconstruction efforts.

“The Japanese will be doing the tests; it is their test and their data and then we will collaborate with them to do all of these measurements,” says Koliou. “We will have our own instruments and we will do all of these measurements to identify and collect time-sensitive data for repair and restoration.”

Koliou says that this wood-frame structure resilience testing is the first of several that will use this experiment to then conduct similar tests on concrete and steel buildings. The experiment will work to collect data from four models of restoration, repair and damage of the structure while taking into account the interplay of structural and non-structural components, their structural interaction and the utility lines.  

“Different levels of earthquake shaking will be used for the two wood structures until total collapse," said Koliou. "We are expecting to observe heavy damage on both structures and potential implementation of seismic retrofit techniques,” says Koliou.

The importance and purpose of this test, according to Koliou, will be to use the qualitative data collected to minimize uncertainty and create robust models that capture the exact interactions between the soil, utilities and structural and non-structural components.

“The ultimate goal of this project is to investigate the response of these structures experimentally and then develop analytical models to capture the actual response of the buildings," said Koliou "[ This will account] for the interaction of structural and nonstructural components, soil-structure interaction, and lifeline utility performance,” said Koliou.

 Koliou said that she has highlighted the differences of Japanese buildings from American buildings and will be aware of them as the tests carry out. However, she said that while there are some differences, there is a large degree of structural similarity, and this project will benefit both teams.

“This is a unique opportunity to collaborate with our Japanese colleagues in one-of-a-kind tests, [on] the world’s largest shake table, where you can actually represent, as realistic as possible, current wood-frame building construction,” said Koliou. “It is really important that there is a very large degree of similarity between the way that the wood-frame residential buildings are built in Japan and in the U.S. We can extrapolate results that would be of benefit to the U.S. and the U.S. communities."

The first collaboration meeting between the US and Japanese teams took place last May in Miki City and Kobe Japan. A dedicated webpage with the progress and focus of this project can be found here.