本文選題：結(jié)構(gòu)狀態(tài)評估 + 古建筑木結(jié)構(gòu)�。� 參考：《北京交通大學(xué)》2017年博士論文

【摘要】：古代建筑是先人為我們留下的珍貴文化瑰寶,具有歷史、文化、科技、藝術(shù)等多方面價值。古代建筑建造年代久遠(yuǎn),在其服役過程中會受到環(huán)境荷載作用及材料老化等不利因素,結(jié)構(gòu)不可避免的產(chǎn)生損傷積累和抗力衰減。使得很多古建筑的結(jié)構(gòu)安全狀態(tài)令人擔(dān)憂,甚至具有局部破壞或整體坍塌的可能性。這不僅會帶來巨大的經(jīng)濟(jì)損失和人員傷亡,從遺產(chǎn)保護(hù)的角度來說,這種破壞帶來的后果是災(zāi)難性的。因此,對古建筑結(jié)構(gòu)的安全性進(jìn)行評估是非常重要和緊迫的。考慮到古建筑材料受自然環(huán)境影響而退化;結(jié)構(gòu)內(nèi)部構(gòu)件連接松動會導(dǎo)致節(jié)點(diǎn)剛度退化;結(jié)構(gòu)內(nèi)部損傷累積導(dǎo)致承載力較弱,不宜通過加載試驗(yàn)確定結(jié)構(gòu)參數(shù),本文的主要目的是提出基于環(huán)境激勵的結(jié)構(gòu)工作狀態(tài)評估方法。工作狀態(tài)評估內(nèi)容主要包括安全性、適用性和耐久性三個方面。安全性是指結(jié)構(gòu)承載能力評估,與結(jié)構(gòu)和構(gòu)件剛度和穩(wěn)定性能有關(guān);適用性是指結(jié)構(gòu)的工作極限狀態(tài)評估,與結(jié)構(gòu)和構(gòu)件在荷載作用下的變形、振動等有關(guān);耐久性主要指對結(jié)構(gòu)損傷的評估。為達(dá)成上述研究目的,擬解決如下三個問題:1)在不同荷載作用下,結(jié)構(gòu)的動力特性如何?2)作用在結(jié)構(gòu)上的荷載情況如何考慮?3)古建結(jié)構(gòu)中未知的節(jié)點(diǎn)參數(shù)和邊界條件如何確定?因此,本論文的研究內(nèi)容主要如下:本文研究目的是提出適用于古代建筑的結(jié)構(gòu)狀態(tài)性能評估方法。(1)對結(jié)構(gòu)健康監(jiān)測的數(shù)據(jù)分析表明,外荷載與結(jié)構(gòu)參數(shù)的變化對結(jié)構(gòu)自振頻率和阻尼比均有顯著影響。利用結(jié)構(gòu)動態(tài)測試數(shù)據(jù)來診斷結(jié)構(gòu)是否發(fā)生損傷,進(jìn)而提出修復(fù)方案,其最大優(yōu)點(diǎn)是將導(dǎo)致結(jié)構(gòu)振動的外界因素作為激勵源,可以在不進(jìn)行加載的情況下完成結(jié)構(gòu)損傷的在線監(jiān)測與診斷。本部分詳細(xì)介紹了結(jié)構(gòu)動力監(jiān)測系統(tǒng),研究了該結(jié)構(gòu)在多種荷載作用下的動力響應(yīng)特性及結(jié)構(gòu)狀態(tài),并基于長期的監(jiān)測數(shù)據(jù),計(jì)算得到結(jié)構(gòu)在不同工作狀態(tài)下結(jié)構(gòu)動力性能參數(shù)變化的情況,為監(jiān)測系統(tǒng)構(gòu)建合理的預(yù)警機(jī)制,獲得相對完備的安全狀態(tài)評估系統(tǒng)所需信息及評價指標(biāo)做出貢獻(xiàn),并得到如下成果與結(jié)論:通過為期三年的動力監(jiān)測,基于協(xié)方差驅(qū)動狀態(tài)子空間法和奇異譜分解法分析獲得了結(jié)構(gòu)響應(yīng)與客流數(shù)量、溫度和地震作用的關(guān)系。其中結(jié)構(gòu)的第一、三階頻率更容易受到人群荷載的影響,在分析游客數(shù)量對結(jié)構(gòu)作用影響時該兩階頻率對應(yīng)的信號可以作為主要研究對象;結(jié)構(gòu)第一、二階頻率更容易受到溫度變化的影響,在溫度對結(jié)構(gòu)作用影響時該兩階頻率對應(yīng)的信號可以作為主要研究對象;地震作用對結(jié)構(gòu)的頻率和加速度信號有很重要的影響,但作用將會在一段時間后消失。地震作用將激發(fā)結(jié)構(gòu)更多頻率峰值的出現(xiàn),同時原有的一些頻率對應(yīng)的峰值會被削弱。(2)建筑結(jié)構(gòu)在正常使用情況下受到人群荷載、溫度荷載、地震作用和風(fēng)荷載等多種荷載的作用。如何反映建筑結(jié)構(gòu)上的真實(shí)荷載狀況,對建筑結(jié)構(gòu)的正常維護(hù)、安全運(yùn)營、損傷識別和狀態(tài)評估具有重要意義。特別是溫度荷載對大跨結(jié)構(gòu)、高層建筑結(jié)構(gòu)以及古建木結(jié)構(gòu)影響很大。因此本文提出了可同時識別結(jié)構(gòu)上外部荷載及溫度荷載的計(jì)算方法。該方法可在溫度荷載信息不完備的情況下,將溫度荷載從結(jié)構(gòu)外部荷載中進(jìn)行解耦,從而獲得作用在結(jié)構(gòu)上的準(zhǔn)確荷載情況。該部分成果與結(jié)論如下,此方法可以克服測量噪聲的影響,準(zhǔn)確的識別出作用在結(jié)構(gòu)上的外部荷載及環(huán)境荷載。數(shù)值模擬計(jì)算結(jié)果表明,當(dāng)考慮10%測量噪聲影響時,環(huán)境荷載識別結(jié)果與理想值誤差小于8%,因此可以認(rèn)為該方法可以準(zhǔn)確的識別環(huán)境荷載,為古建筑狀態(tài)評估提供了理論依據(jù)。(3)結(jié)構(gòu)參數(shù)識別是建立健康監(jiān)測系統(tǒng)、進(jìn)行結(jié)構(gòu)損傷識別與狀態(tài)評估工作的基礎(chǔ),對維護(hù)現(xiàn)役結(jié)構(gòu)的安全與正常運(yùn)營有重要的意義�？紤]到古建筑結(jié)構(gòu)節(jié)點(diǎn)連接方式復(fù)雜,剛度未知,本文提出了一個基于溫度靈敏度法對結(jié)構(gòu)參數(shù)進(jìn)行識別并對依據(jù)結(jié)構(gòu)初始狀態(tài)建立的有限元模型予以修正的計(jì)算方法。在模型建立中,考慮了構(gòu)件之間的摩擦作用、存在的縫隙以及暗銷的剪切作用,更為準(zhǔn)確的模擬了古建筑的工作情況。該方法基于結(jié)構(gòu)動力監(jiān)測數(shù)據(jù),建立了系統(tǒng)輸入(環(huán)境荷載)與系統(tǒng)輸出(結(jié)構(gòu)響應(yīng))之間的關(guān)系,從而對結(jié)構(gòu)中剛度不確定的構(gòu)件進(jìn)行了準(zhǔn)確的參數(shù)識別并提出了一種有效的邊界條件簡化方式,以便更合理的表示出古建筑木結(jié)構(gòu)狀態(tài)的變化,進(jìn)而為古建筑狀態(tài)評估奠定基礎(chǔ)。計(jì)算結(jié)果表明,該方法抗噪性強(qiáng),準(zhǔn)確度高。將基于該方法計(jì)算得到的結(jié)果與通過環(huán)境激勵法計(jì)算結(jié)果對比,驗(yàn)證了計(jì)算方法的可靠性。在此基礎(chǔ)上,對該算法中的計(jì)算參數(shù)進(jìn)行分析,得到了數(shù)據(jù)長度、溫差大小及傳感器布置情況對計(jì)算結(jié)果的影響。
[Abstract]:Ancient architecture is a precious cultural treasure left for us by the ancestors. It has many aspects of history, culture, science and technology, art and so on. Ancient architecture was built for a long time. In the course of its service, it will be subjected to adverse factors such as environmental load and material aging. The structure inevitably produces damage accumulation and resistance attenuation. It makes many ancient buildings. The state of structural safety is worrying, even with the possibility of local damage or overall collapse. It not only brings huge economic losses and casualties, but the consequences of this destruction are catastrophic from the point of view of heritage protection. Therefore, it is very important and urgent to assess the safety of the structure of the ancient buildings. The ancient building materials are degenerated by the natural environment, and the looseness of the structural internal components will lead to the degeneration of the stiffness of the joints; the internal damage accumulation in the structure leads to the weak bearing capacity. It is not suitable to determine the structural parameters through the loading test. The main purpose of this paper is to put forward the evaluation method of the working state based on the environmental excitation. It mainly includes three aspects of safety, applicability and durability. Safety refers to the evaluation of structural bearing capacity, which is related to structure and component stiffness and stability performance; applicability refers to the evaluation of the working limit state of the structure and the deformation and vibration of the structure and components under the load; the durability mainly refers to the assessment of structural damage. The purpose of this study is to solve the following three questions: 1) how is the dynamic characteristics of the structure under different loads? 2) how to consider the load situation on the structure? 3) how to determine the unknown node parameters and boundary conditions in the ancient construction structure? Therefore, the main contents of this paper are as follows: the purpose of this paper is to put forward the application The structure state performance evaluation method of the ancient building. (1) the data analysis of the structural health monitoring shows that the changes of the external load and the structural parameters have significant influence on the vibration frequency and damping ratio of the structure. As the excitation source, the vibration monitoring and diagnosis of structural damage can be completed without loading. The structural dynamic monitoring system is introduced in detail, and the dynamic response characteristics and structure state of the structure under various loads are studied, and the structure is calculated based on the long-term monitoring data. The changes in the dynamic performance parameters of the structure under different working conditions have contributed to the construction of a reasonable warning mechanism for the monitoring system and the information and evaluation indexes required for a relatively complete safety state assessment system. The following results and conclusions are obtained: the covariance driven state subspace method and the odd one are obtained through three years of dynamic monitoring. The relationship between the structure response and the number of passenger flow, the temperature and the earthquake action is obtained. The first, third order frequency of the structure is more easily affected by the load of the crowd. The signal corresponding to the two order frequency can be used as the main object in the analysis of the influence of the number of tourists on the structure. The first, second order frequency of the structure is more capacitive. It is easy to be affected by the temperature change, the signal corresponding to the two order frequency can be used as the main research object when the temperature is affected by the structure. The seismic action has a very important influence on the frequency and acceleration signal of the structure, but the effect will disappear after a period of time. Some of the corresponding peaks will be weakened. (2) under normal use, the building structure is subjected to a variety of loads, such as crowd load, temperature load, earthquake action and wind load. How to reflect the real load status in the building structure is important for the normal maintenance of the building structure, safety operation, damage identification and state assessment. In particular, the effect of temperature load on large span structure, high-rise building structure and ancient construction wood structure is very important. Therefore, this paper proposes a method to identify the external load and temperature load on the structure simultaneously. This method can decouple the temperature load from the external load of the structure under the condition of incomplete temperature load information. The results and conclusions are obtained as follows. This method can overcome the influence of measurement noise and accurately identify the external load and environmental load on the structure. The results of numerical simulation show that the error of environmental load identification is smaller than that of the ideal value when the effect of 10% measurement noise is considered. In 8%, it can be considered that this method can accurately identify the environmental load and provide a theoretical basis for the assessment of the state of ancient buildings. (3) the identification of structural parameters is the foundation of establishing a health monitoring system, which is the basis of structural damage identification and state assessment, and is of great significance for the maintenance of the safety and normal operation of the active service structure. The connection mode of structural nodes is complex and the stiffness is unknown. In this paper, a method based on the temperature sensitivity method to identify the structural parameters and to modify the finite element model based on the initial state of the structure is proposed. In the model, the friction between the components, the existing cracks and the shear effect of the pin are considered. It is more accurate to simulate the work of ancient buildings. Based on the dynamic monitoring data of the structure, the relationship between the system input (environmental load) and the system output (structural response) is established, thus the accurate parameter identification of the components with uncertain stiffness in the structure is identified and an effective method of boundary condition simplification is proposed. It is more reasonable to show the change of the structure state of the ancient building wood, and then lay the foundation for the assessment of the state of the ancient building. The calculation results show that the method has strong anti noise and high accuracy. The results of the calculation based on this method are compared with the results calculated by the environmental excitation method, and the reliability of the calculation method is verified. On this basis, the algorithm is used in the algorithm. The calculation parameters are analyzed, and the influence of data length, temperature difference and sensor layout on the calculation results is obtained.

【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：TU-87
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本文編號：1873753