Seismic strengthening of existing typical Japanese wood homes using GFRP systems

Abstract

It is estimated that out of existing 47 millions homes in Japan, approximately 11.5 million need urgent strengthening. These homes do not meet current earthquake resistant standards and would face severe damage in the event of a “Shindo” 7 quake as it is know on the Japan Meteorological Agency’s seismic intensity scale. Wooden houses in Japan are typically built by wood post-and-beam methods over a concrete strip foundation. Due to the constant mild seismic activity many of the existing homes have been further weakened with evidence of cracks in the foundation and in the wood-mortar walls. The currently available seismic strengthening systems involve a massive amount of intrusive work to the existing homes and are beyond the budget of an ordinary Japanese family. This paper serves as a case study, from Concept to Implementation, into how an affordable minimally intrusive seismic strengthening system was developed to strengthen typical Japanese wooden houses for earthquakes resistance by using Glass Fibre Reinforced Polymers (GFRP) materials. It will highlight the concept for the concrete strip foundation and the concept for the wood-mortar wall strengthening with GFRP as well look into specific details of four years of research and development with the participation of Kyushu University in Japan, Nanyang Technological University in Singapore and Oita University