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Damage to buildings or houses in strong wind like typhoon or tornado are caused by flying debris such as roof tile in most cases. Measuring aerodynamic characteristics of flying debris is required to predict the motion of flying debris and to evaluate the impact for the wind resistant design of claddings and the reduction of damage to houses. This study aims to measure the aerodynamic characteristics of flying debris. Stand-alone measuring device assembled with microcomputer, three-axes accelerometer, gyro sensor, pressure sensors, SD card and small battery was built in three types of models of flying debris. These models were dropped from the stage located at 50m in the dome with no wind, and pressures, acceleration and angular velocity were measured, while capturing the motion of models by taking movies with video cameras and conducting image analysis. Based on the result of the measuring, the motion and wind force acting on each model was calculated.

Damages to houses in strong wind, e.g. typhoon or tornado, are caused by flying debrisin most cases. The configuration of flying debris such as branches of tree, pebbles, piecesof broken structures and so on is categorized as a "bluff body". Therefore, prediction offlying motion of bluff body is important to evaluate the impact of flying debris for thewind resistant design of claddings and the reduction of damage to houses.This study aims to develop a system to measure the motion of bluff body and to clarifyaerodynamic characteristics of flying debris. Some units of micro-computer, three axisaccelerometer, pressure sensors, A/D converter, Wi-Fi adaptor and small battery wereassembled as a stand-alone probe to measure the motions and wind forces on a flyingbody. The measuring probe was built in a rectangular shaped test body. The test body wasdropped in a test region with no wind. The pressure and the acceleration on the test bodywere measured, while capturing the motion of the body by taking movies with videocameras and conducting image analysis.

It is known that wind damage to houses is affected by wind speeds. Furthermore, the numerous conditions of constructions such as roof forms and materials influence increases in wind damage. It is clear that the roof forms and materials of houses are linked to winter climatic conditions like temperature and snow accumulation. The climatic condition in a cold snowy region, which has close relation to roofs of houses, seems to be related to increases in roof damage. The authors show a strong correlation between snow accumulations and roof forms of houses in a cold snowy region quantitatively. Residential damage rates which are estimated using not only winds but snow accumulations in place of roof forms of houses correspond with actual damage rates resulting from strong winds. If we use data which are easy to obtain like temperatures and snow accumulations, residential damage rates affected by structural condition may be estimated.

It is known that the wind damage spreading of residential houses is more strongly affected by gust speeds rather than maximum wind speeds. Furthermore, the age and the structure of buildings influence outbreaks of wind damage. The authors proposed the method to estimate residential damage rate associated with typhoon by considering wind-resistant performance of houses and strong winds. The residential damage rate has been better estimated using modified wind speeds associated with building structure distributions in municipalities. Residential damage rate due to strong winds might be able to estimate better considering performances of houses such as roof form, exterior material and maintenance. Considerable affecters to estimate residential damage rate more correctly should be established.

It is known that the wind damage spreading to residential houses is more strongly affected by gust speeds rather than maximum wind speeds. Authors have examined the effects of wind properties on residential damage due to typhoons. However it was not easy to indicate a clear correlation between properties of wind and damage, because the structural damage associated with strong winds is strongly affected by the various characteristics of structures. In this paper, we tried the damage analyses by quantifying the characteristics of buildings based on the information associated with Typhoon Bart(1999) and Typhoon Songda(2004). It was found that a rate of wooden buildings in an area has correlation to the residential damage due to the typhoons. Naturally if there are many aged buildings in the area, the wind damage of residential houses is spread. It is suggested that the characteristics of buildings as well as the gust speeds is a significant factor of spreading of structural damage.

気象庁では、10分間内の風速変動を細かく観測して、0.25秒毎の「瞬間風速」の10分間内での最大値を「最大瞬間風速」と呼ぶ。また、その「瞬間風速」の平均値を「10分間平均風速」と呼ぶ。これらの、「最大瞬間風速」を「10分間平均風速」で除した値を「突風率」(またはガストファクター)と呼ぶ。従来、この「突風率」は1.8 程度といわれているが、気象条件や地形によって変わることが指摘されている。この「瞬間風速」が大きい場合は突風災害が起きることがあるので、「突風率」を推定して、突風予測に結びつけることができれば理科教育と防災に役立てることが出来る。同様な目的をもった林ら(2008)の近畿地方の研究に引き続き、関東地方を対象領域として、1年間の気象データを収集・解析し、「突風率」を推定する次の実験式を得た。Y=-0.00188x+2.29(5≦x≦21)ただし、Yは「突風率」、xはm / s単位の「10分間平均風速」である。

気象庁では、10分間内の風速変動を細かく観測して、0.25秒毎の「瞬間風速」の10分間内での最大値を「最大瞬間風速」と呼ぶ。また、その「瞬間風速」の平均値を「10分間平均風速」と呼ぶ。これらの、「最大瞬間風速」を「10分間平均風速」で除した値を「突風率」(またはガストファクター)と呼ぶ。従来、この「突風率」は1.8程度といわれているが、気象条件や地形によって変わることが指摘されている。この「瞬間風速」が大きい場合は突風災害が起きることがあるので、「突風率」を推定して、突風予測に結びつけることができれば理科教育と防災に役立てることが出来る。このような目的をもって近畿地方を対象領域として、1 年間の気象データを収集・解析し、「突風率」を推定する次の実験式を得た。y=-0.0316x+ 2.26(5≦x≦24) ただし、yは「突風率」、xはm / s単位の「10 分間平均風速」である。

1999年9月24日に九州地方を縦断した台風9918号は, 熊本県鹿島村で最大瞬間風速83m/sを記録するなど, 各地で記録を更新する強風が吹き, 八代海沿岸地域で高潮による死者12人を含む甚大な人的・建物・鉄塔・農林被害をもたらした, 本報では現地調査および航空機による空からの被害調査を行い, 建物の被害状況や航空機からの映像によるシート率の分布を求め, 建物被害率との関係を検討した, また, 建物被害率と気圧場から推定した風速との関係も求めた., The damage of buildings and houses by Typhoon 9918 along Yatsusiro Sea was studied. The damage rate of buildings and houses was obtained.The sheet rate was also calculated by the aerial photos. The relation of these values was examined.The relation between the damage rate and the maximum gust wind speed was also evaluated.

台風9807号による建物の強風被害調査を行い, 建物の被害分布, 近畿圏の主な歴史的建造物の被害の概要を明らかにした。とくに, 建物の被害が多かった奈良盆地における市町村別の建物強風被害について, 被害把握に対する航空写真の有効性と問題点について検討を行った。その結果, 世帯ごとに求めた建物被害率と航空写真から求めた建物の被害率との間には市街地において良い相関があり, 建物強風災害の把握に有効であることがわかった。, Strong wind damages to buildings and houses by Typhoon 9807 were investigated. The damage rate was obtained from public reports and field investigation. The rate of buildings and houses covered with the sheet shielding from the rain, here we call "sheet rate", was counted by the aerial photos. These two damage rates have a good correlation in the urban area in Nara Basin.