Analysis of Wind Loading Coefficients of Wind Resistant Design Code(III)

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基本資料

Project title

Code/計畫編號

NSC98-2221-E019-016

Translated Name/計畫中文名

耐風設計規範風力計算相關係數研究(III)

Project Coordinator/計畫主持人

Jing-Jong Jang

Funding Organization/主管機關

National Science and Technology Council

Co-Investigator(s)/共同執行人

林博雄

Department/Unit

Department of Harbor and River Engineering

Website

https://www.grb.gov.tw/search/planDetail?id=1913122

Year

2009

Start date/計畫起

01-08-2009

Expected Completion/計畫迄

01-07-2010

Bugetid/研究經費

503千元

ResearchField/研究領域

土木水利工程

"台灣地處北太平洋西部的亞熱帶地區，為熱帶氣旋盛行的地方，在夏秋兩季經常會遭受到熱帶氣旋（台灣慣稱颱風）的侵襲，而颱風所挾帶的強風豪雨，使得建築物在風雨效應下，受到風與雨兩者作用而受力增加。然而，國內對風力之研究，部分承襲美國與日本之風力規範，但是臺灣氣候是屬於複雜的亞熱帶海島型氣候，在颱風來臨時，其溫度、濕度及大氣壓力等特性皆不同於歐美日規範考量之氣候，所以在防風設計上仍有許多部分需考量台灣之地理、氣候等條件而提出修正。因此本計劃將針對颱風來臨時，建築物面臨之風與雨同時作用下之影響。本研究為三年期計畫，第一年已執行的研究計劃是利用可降水量之觀念導出颱風來臨時之飽和空氣密度，以求得隨高度變化之風速壓力與設計風力，再引入陣風反應因子即得建築物之設計風力。再來利用粒子動量方程之原理，模擬各粒徑之雨滴軌跡求出其水平雨速，利用水平雨速及直接降雨強度計算橫埽雨量強度。第二年已執行的研究計劃是推求適合本國地理特性之風速剖面參數，過去因國內無相關本土自然風場資料及相關研究，致現行規範對風速剖面之係數之取捨大致依偱美、日規範。利用蒐集中央氣象局與中華民國空軍探空氣球實測數據，繼而初步運用本土自然風場數據加以分析推求更適用於台灣的α及Zg 值。而第三年將統合前二年研究成果，並考慮本土特性的空氣密度ρ值與風速剖面α、Zg 值，並針對空氣密度與風雨作用力做更合理的推估與計算。蒐集中央氣象局、台灣大學與中華民國空軍探空氣球實測數據、中央氣象局所屬氣象測站取得風速資料、國立中央大學大氣科學系雨滴譜儀提供雨的資料及淡江大學風工程研究中心量測的自然風場監測數據，收集近年來颱風橫掃臺灣所測得到之大氣資料如：可降水量、溫度、高度、濕度、大氣壓力、飽和水汽壓…等及常年風速資料。並以一高樓層範例進行模擬比較分析，探討影響差異程度，提供未來高樓耐風設計分析參考。探討臺灣地區颱風來臨時風雨作用力特性，以提供未來結構耐風設計分析及規範條文修訂之參考。相信本計畫之順利執行，研究成果將可提高和加強建築結構物抗颱風之安全可靠度。" "Taiwan is a subtropical island and located at the Pacific Ocean Rim where earthquake and typhoons occurred frequently and lots of building and bridge structures damaged every year. Usually, Typhoon comes with heavy rain in summer. Such as 1996 Herb typhoon and 1997 Winny typhoon. Both typhoons caused billions of economic loss for Taiwan. It is very important for us to design wind resistant structures in addition to predict the location, path and strength of typhoon which will strike Taiwan island in order to reduce properties damage and economic loss or prevent life loss. The current Taiwan building code for wind resistant design was published in 1974, and revised by Prof. Tasi in 1996 and reviewed by Architecture and Building Research Institute in 2004. Basically, it is based on USA’s ANSI/ASCE 7-2002 and Japan’s AIJ-96 building codes. The wind pressure q(Z ) is the function of the values of the wind speed profile α and Zg. The wind speed profile coefficient introduction into the current building code for wind resistant design is based on the codes of USA and Japan. There are no data or researches about the natural wind filed of Taiwan. Thus, this research will study the wind speed profile which approach to the characteristic of geography in Taiwan. This is a 3 years research proposal. First, we will collect the climate data such as: the atmospheric like precipitable water、 temperature、 height、 humidity、atmospheric pressure、 saturation vapor pressure、drop size of raindrops and the terminal velocity of a raindrop of Taiwan from the National Weather Bureau and National Taiwan University 、 Central University and Wind Engineering Research Center of TamKang University. This year, we will study the wind-driven-rain effect for the air density which is varied with height during typhoon based on the results of the first two years. The horizontal velocity of the raindrop will calculated by the equation of motion of the particles. Using the driven-rain intensity coefficient Cdr(Ih) the driven-rain intensity can be obtained. On the other hand, with reference to wind speed profile we will use the different instrument to sampling、 analyze and compare with real data and regression the value to calculate the design wind loading coefficient during typhoon. At last, a tall building example will be set up. Structural analysis and simulation will be performed to study the dynamic behavior of structure by using computer program. The building is subjected to both wind and wind-rain pressure loading. The results and conclusions or suggestions of this research will be helpful for future structure design code revised with wind-rain effect consideration. It will also useful for the future building design code and benefit the whole society."

Keyword(s)

風力係數
風速剖面
空氣密度
風雨效應
Wind Loading Coefficient
Wind Speed Profile
Air Density
Wind-Rain Effect

DSpace CRIS

Analysis of Wind Loading Coefficients of Wind Resistant Design Code(III)

基本資料

Description