Earthquake! Are Your Home and City Safe?

Japan is one of the most earthquake-prone countries in the world, and its natural conditions, such as topography and ground, are often extremely vulnerable to natural disasters. As a result, earthquakes have claimed many lives and destroyed homes and cities (see Photo 1).

Meanwhile, the environment surrounding architecture is situated within a technological and advanced information society characterized by unprecedentedly massive energy consumption. To address this, it is necessary to establish a framework for a new era of architectural structural systems that integrates with new technological fields, creating a future-oriented, proposal-based total system.

Against this backdrop, our laboratory aims to create safe and secure homes and cities that can minimize damage from major earthquakes. We are conducting research on earthquake-resistant technologies for buildings, with a particular focus on developing smart building structures. Specifically, this involves building future-oriented smart structural systems based on conventional earthquake-resistant, base-isolated, and vibration-controlled structural systems (see Figure 1).

The main research themes in our laboratory include (1) evaluation of earthquake ground motion and ground vibration, (2) safety evaluation of base-isolated and vibration-controlled structures, and (3) health assessment of buildings based on monitoring. In conducting these evaluations, we are building smart structural systems that incorporate the biological functions of living organisms.

As part of our development of smart structural systems, we present an example of applying smart materials (such as shape-memory alloys and piezoelectric elements) to buildings. Photo 2 shows the results of an experiment on a reinforced concrete member using a shape-memory alloy for its main reinforcement (from a U.S.-Japan cooperative research project). Other systems include those that suppress building vibrations using methods like genetic algorithms, neural networks, and fuzzy theory, as well as systems that assess a building's safety by identifying the location and degree of damage.

Photo 2-1

Photo 2-2

Photo 2-3

This shows a static loading test on a mortar member applying the superelastic effect of a shape-memory alloy. The cracks that appeared at maximum load closed after the load was removed, and the member returned to its original shape. This signifies the emergence of a member with a self-healing function, one of the features of a biological system.

One day in the 21st century... I am confident that buildings will possess biological functions, be gentle to humans and nature, achieve ultimate energy savings with maximum energy efficiency, and also contribute significantly to solving issues such as the aging society and global environmental problems.