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Cryptotermes brevis - a silent earthquake for the wood structures in a World Heritage city in the Azores Islands
2016 - IRG/WP 16-50316
In the Azores archipelago the exotic drywood termite Cryptotermes brevis, detected in early 2000’s, is destroying the wood structures of the typical buildings and is already considered the main urban pest in these islands. This work aims to show the spread evolution of this pest along the last six years in the first Portuguese city classified as world heritage by UNESCO, Angra do Heroísmo. For six years, several buildings were monitored, using traps with glue to catch the alates (flying individuals), during the swarm season that occurs, normally, from the late spring until the end of summer. The number of captured individuals was used to determine the density per building. This data was analysed with a GIS in order to build risk maps of the termite spread in space along time. The results clearly indicate that the pest species is expanding. The city centre is no longer the only affected area. The percentage of buildings that are affected or in risk to be affected is very high in the entire city. Traditional construction, with timber load bearing structures, is being replaced by metal or other materials. There is still no Integrated Urban Pest Management implemented in the region or in the city. Therefore, with time, timber structures might become restricted to exist only in buildings like museums, churches or palaces.
O Guerreiro, P A V Borges, L Nunes


The Influence of Wood Included Salinity on Nail
2019 - IRG/WP 19-40863
In the Great East Japan Earthquake that occurred on March 11, 2011, many buildings suffered from natural seawater dipping due to the tsunami. It has become clear that corrosion progresses in nail that had submerged in natural seawater compared to nail that had not submerged in natural seawater. However, processing for this has not been developed. Therefore, in this research, we experimentally explored the possibility of continuous use of nail in wooden building submerged in natural seawater by tsunami. In order to verify the usefulness of rinsing by fresh water, the following experiment was conducted. At first, the wood specimens with nail was submerged in natural seawater, artificial seawater, and sodium chloride solutions. Nails were driven into the wood specimens before submerged and after submerged. Secondly, the rust of specimens, which was rinsed by fresh water or not, was quantified after promoting accelerated rusting. The nail was visually confirmed that the progress of corrosion was suppressed in the nail which was rinsed with fresh water after submerged in natural seawater. However, no significant difference in the degree of corrosion due to the presence or absence of rinsing with fresh water from the quantification of the rust. Each study result was subjected to a significant difference study for each submerged period depending on the presence or absence of rinsing with fresh water. Regarding the calculation results, from this study, there is no significant difference in rinsing with fresh water under any condition, I seemed that it was ineffective. In conclusion, it was confirmed that fresh water rinsing may be inappropriate as a countermeasure against nail that submerged in the natural seawater.
R Nakano, H Ishiyama, K Sakano