本文關(guān)鍵詞：溫度對橋梁模態(tài)頻率識別的影響研究　出處：《吉林大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 橋梁 溫度 模態(tài)頻率 彈性模量 變化趨勢

【摘要】：交通是社會經(jīng)濟發(fā)展大動脈,橋梁則是保障交通暢通的首要因素。為保證社會經(jīng)濟持續(xù)發(fā)展和進步,橋梁功能的完整性,尤其是安全性則顯得尤為重要。統(tǒng)計數(shù)據(jù)表明,隨著近年來我國基礎(chǔ)設(shè)施建設(shè)大力發(fā)展,我國橋梁建設(shè)取得了舉世矚目的成就,每年有大量新橋陸續(xù)建成,為使公路橋梁安全運行,則需要對這些剛剛完工的橋梁進行承載力評定和必要的健康監(jiān)測。另一方面,許多已建橋梁經(jīng)過長期服役而缺少足夠充分的管養(yǎng),已經(jīng)接近設(shè)計壽命；橋梁的老化和損壞的現(xiàn)象層出不窮,對既有橋梁進行可靠鑒定以及損傷識別則迫在眉睫。近年來,以振動的結(jié)構(gòu)損傷為基礎(chǔ)的識別方法在得到了廣泛發(fā)展,同時也成為了土木工程的研究重點,而溫度對橋梁模態(tài)頻率的影響常常會掩蓋橋梁損傷的存在。本文的實驗研究旨在探求溫度影響模態(tài)頻率的內(nèi)在機理,揭示溫度對橋梁模態(tài)頻率影響的規(guī)律,以及橋梁不同損傷下的模態(tài)頻率變化規(guī)律,為有效的解決溫度對季凍區(qū)橋梁損傷識別問題奠定基礎(chǔ)。 本文的主要研究成果及結(jié)論如下： ①本文研究了溫度效應(yīng)影響橋梁模態(tài)頻率分析并得出以下結(jié)論：溫度的變化改變混凝土的彈性模量是造成橋梁模態(tài)頻率改變的主要原因,同時溫度對混凝土橋梁模態(tài)頻率的影響主要是通過改變混凝土力學(xué)的性質(zhì)來實現(xiàn)的。 ②利用動載試驗識別出小梁在不同溫度下的模態(tài)頻率。并做數(shù)據(jù)的相關(guān)性分析后,得出結(jié)論：橋梁的頻率隨環(huán)境溫度的升高而降低,兩者之間呈良好的線性負(fù)相關(guān)關(guān)系。 ③依托實際橋梁檢測工程進行了橋梁溫度、濕度的測試,并進行現(xiàn)場動載實驗。結(jié)果表明橋梁的自振頻率變化與外界環(huán)境變化表現(xiàn)出較好的相關(guān)性。同時,橋梁的自振頻率與環(huán)境溫度數(shù)值之間的相關(guān)系數(shù)較大,說明橋梁的自振頻率的變化主要受溫度的影響。在實際橋梁健康評價工作中,溫度確實會對橋梁的模態(tài)頻率識別產(chǎn)生影響。若在較低溫度環(huán)境下測得的結(jié)構(gòu)發(fā)生損傷后的模態(tài)頻率,就可能得出該已損傷橋梁結(jié)構(gòu)“沒有損傷”,或者“運行狀態(tài)良好”的錯誤結(jié)論。說明了在橋梁健康監(jiān)測中,剔除環(huán)境因素對橋梁模態(tài)頻率的淹沒作用至關(guān)重要。
[Abstract]:Traffic is the main artery of social and economic development, and bridge is the primary factor to ensure the smooth flow of traffic. In order to ensure the sustainable development and progress of social economy, the integrity of bridge function is ensured. Especially security is particularly important. Statistics show that with the rapid development of infrastructure construction in recent years, bridge construction in China has made remarkable achievements, and a large number of new bridges have been built one after another every year. In order to ensure the safe operation of highway bridges, it is necessary to evaluate the carrying capacity and necessary health monitoring of these newly completed bridges. On the other hand, many of the bridges that have been built have been in service for a long time and lack sufficient management and maintenance. Close to design life; The aging and damage of bridges emerge in endlessly, so it is urgent to identify the existing bridges reliably and damage. In recent years, structural damage identification based on vibration has been widely developed. At the same time, it has become the focus of civil engineering research, and the influence of temperature on the bridge modal frequency will often cover up the existence of bridge damage. The purpose of this experiment is to explore the intrinsic mechanism of temperature influencing modal frequency. The influence of temperature on bridge modal frequency and the variation of bridge modal frequency under different damage conditions are revealed, which lays a foundation for the identification of bridge damage caused by temperature in seasonal frozen region. The main research results and conclusions are as follows: 1. This paper studies the effect of temperature on the modal frequency analysis of bridges and draws the following conclusions: the change of the elastic modulus of concrete is the main reason of the bridge modal frequency change. At the same time, the influence of temperature on the modal frequency of concrete bridges is mainly realized by changing the mechanical properties of concrete. (2) the modal frequencies of the trabeculae at different temperatures are identified by dynamic load test. After the correlation analysis of the data, it is concluded that the frequency of the bridge decreases with the increase of ambient temperature. There is a good linear negative correlation between the two. (3) based on the actual bridge detection project, the temperature and humidity of the bridge are tested, and the field dynamic load experiment is carried out. The results show that the natural vibration frequency of the bridge has a good correlation with the change of the external environment, and at the same time. The correlation coefficient between the natural vibration frequency of the bridge and the value of ambient temperature is large, which indicates that the change of the natural vibration frequency of the bridge is mainly affected by the temperature. The temperature does influence the modal frequency identification of the bridge. If the modal frequency of the damaged structure is measured in the lower temperature environment, it may be concluded that the damaged bridge structure has no damage. Or the wrong conclusion of "good running state" shows that it is very important to eliminate environmental factors in bridge health monitoring for bridge modal frequency inundation.
【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：U441;U446

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