發(fā)布時間：2018-01-25 18:44

  本文關鍵詞： 懸索橋主纜 溫度效應 熱物性參數(shù) 溫度應力 施工監(jiān)控　出處：《重慶大學》2015年博士論文　論文類型：學位論文

【摘要】：大跨度懸索橋主纜為橋梁的主要承重結構,其性能決定了懸索橋的跨越能力和承載能力,但溫度的變化對其內(nèi)力和線形有著顯著影響。由于懸索橋主纜為組合結構,其導熱機理較復雜,當外部環(huán)境溫度變化較大時,主纜與外部環(huán)境以對流與輻射等多種形式進行熱交換,主纜表面溫度變化迅速,但由于主纜內(nèi)部溫度變換滯后,且隨著主纜直徑變大,滯后現(xiàn)象越顯突出,進而形成明顯的溫度梯度,導致內(nèi)外溫差很大。這種溫差會產(chǎn)生溫度變形,會引起懸索橋主纜結構受力和線形的變化,甚至會產(chǎn)生及大的溫度應力。這種溫度應力和變形影響到懸索橋的安全施工和后期健康運營,但相關溫度研究工作開展較少,也沒有相關的計算規(guī)范。且在大跨度懸索橋施工監(jiān)控中普遍采用主纜實測表面溫度或環(huán)境溫度代替主纜的實際溫度,影響懸索橋施工安全和精度。鑒于以上現(xiàn)狀,在國家西部交通建設科技項目管理中心、重慶市交通委員會的資助下,本文以重慶市最大跨度懸索橋(修建時)為工程背景,對大跨度懸索橋主纜的溫度場計算、溫度應力推導及其效應進行了較為系統(tǒng)的研究,本文所做的工作如下:1.主纜熱物性參數(shù)試驗及溫度場測量研究。本文進行了多工況的主纜模型熱物性參數(shù)測試,對主纜模型的一系列熱物性參數(shù)(表觀熱傳導系數(shù)、表觀熱擴散率、自然對流下的表面換熱系數(shù))進行了穩(wěn)態(tài)測試和非穩(wěn)態(tài)測試,并進行了依托工程現(xiàn)場環(huán)境下即橋址處(晴天、雨天)溫度場測試研究,得到了復雜環(huán)境下主纜溫度場分布規(guī)律;并通過模型實驗的有限元仿真對試驗測試方法的合理性進行了驗證,結果證明主纜橫截面溫度場實測值與計算值基本相符,誤差不大。2.懸索橋主纜溫度場的普適計算方法研究。通過對主纜溫度場分布規(guī)律的分析,以傳熱學、普通天文學以及太陽物理學為理論基礎,研究了對日照溫度效應有所影響的各種因素,如:材料參數(shù)、太陽輻射強度、經(jīng)緯度位置、天氣狀況和橋梁方位等,系統(tǒng)地建立懸索橋主纜結構日照溫度場分析的邊界條件,探討了主纜表面與外部環(huán)境和主纜表面與內(nèi)部之間熱量傳遞的機理,提出了一套懸索橋主纜溫度場的普適計算方法,建立了懸索橋主纜溫度響應的計算模型,進行能夠滿足對任意復雜條件的數(shù)值分析。3.懸索橋主纜三維溫度應力計算方法研究。溫度場及溫度應力現(xiàn)有分析基本是采用有限差分法與有限單元法等數(shù)值方法,計算較復雜且工作量較大,不便于實際應用。基于此,本文對懸索橋主纜結構三維溫度應力的更為簡便、實用的計算方法進行了探討,基于熱彈性力學理論,推導出了懸索橋主纜結構三維溫度應力的一般計算方法,研究了影響懸索橋主纜溫度應力的參數(shù),并對懸索橋主纜溫度應力進行了計算分析,在考慮了泊松效應引起的各應力分量間的藕合作用的同時,能夠實現(xiàn)采用二維問題代替三維問題分析的三維溫度應力空間分析方法,且只需運用結構力學方法即可實現(xiàn)。4.主纜溫度效應分析�；�于對懸索橋主纜的溫度場分布及溫度應力的探討,系統(tǒng)的研究了懸索橋各結構應力、內(nèi)力和變形等主纜溫度變化所帶來的溫度效應,更進一步對懸索橋安全性和耐久性等方面進行了探討。以依托工程為例,系統(tǒng)計算了依托工程主纜索股架設過程索股溫度場及對主纜內(nèi)力、線形及張力差的影響,為減少內(nèi)力和線型的偏差提供依據(jù);評估溫度變化對成橋后主纜的內(nèi)力、線形以及索塔內(nèi)力的影響。5.溫度場與溫度效應計算實例。研究項目直接服務于西南最大懸索橋(修建時)的架設施工,通過對依托工程基準索股架設階段、主纜索股架設階段、大橋索夾定位階段以及加勁梁架設階段等不同季節(jié)主纜溫度場測試研究工作,以試驗結論為依據(jù),對依托工程主纜溫度場和溫度效應進行了計算,研究成果將實測溫度數(shù)據(jù)和計算數(shù)據(jù)進行比較分析,及時調整參數(shù)取值、修正計算模型,保證用于依托在主纜架設控制的主纜溫度場的準確性及可靠性,順利完成了依托工程的施工監(jiān)控工作,主纜上下游高差和橋梁線形達到了目前其他同類橋梁施工尚未達到的目標,確保了施工安全和精度。
[Abstract]:The main load-bearing structure of the main cable of large span suspension bridge bridge, its performance determines the suspension bridge spanning capacity and bearing capacity, but the change of temperature has a significant effect on the internal force and alignment. The main cable of suspension bridge is a composite structure, the heat conduction mechanism is more complicated, when the external environment temperature changes greatly. The main cable and the external environment of the heat exchange by convection and radiation in various forms, the main cable surface temperature changes rapidly, but because of the internal temperature of the main cable transform lag, and with the main cable diameter becomes larger, the hysteresis phenomenon is more prominent, and the formation of the temperature gradient is obvious, resulting in significant difference in temperature inside and outside the temperature will produce temperature. Deformation will cause changes in the structure of the main cable suspension bridge stress and linear, and will even produce large temperature stress. The temperature stress and deformation affect the suspension bridge construction safety and healthy operation of late, but the temperature. The work carried out less, there is no calculation of related specifications. The actual temperature and in the construction control of long-span suspension bridge is widely used in the main cable measured surface temperature or ambient temperature instead of the main cable, affect the bridge construction safety and accuracy. In view of the above situation, in the Western Transportation construction technology project management center, the Chongqing Municipal Transportation Commission under the support of the Chongqing city is the biggest span suspension bridge (built) as the engineering background, the calculation of the temperature field of main cable of large span suspension bridge, the temperature stress is deduced and its effects were studied systematically. The work of this paper are as follows: the experiments and Research on temperature field measurement of thermophysical properties of 1. main cable in this paper the main cable parameters. The model of thermal parameters of multi operating tests on cable model of a series of thermal parameters (apparent thermal conductivity, apparent thermal diffusivity, surface under natural convection heat exchange system The number of steady state test) and non steady state test, and the on-site environment is at the bridge site (Qing Tian, rain) test of temperature field, the complex environment of the main cable temperature field distribution; and through the finite element model of the experimental simulation test method of rationality were verified. The results prove that the main cable cross section temperature field measured values are consistent with the calculated results, method of computing error is small.2. suspension bridge main cable temperature field in general. Based on the analysis of the main cable temperature field distribution, the heat transfer, general astronomy and solar physics as the theoretical basis of various factors, influence the temperature effects of the material parameters, such as the solar radiation intensity, the latitude and longitude location, weather conditions and Bridge orientation, systematically establish the boundary condition of the main cable suspension bridge structure temperature field, discusses the main cable 琛ㄩ潰涓庡�栭儴鐜�澧冨拰涓葷紗琛ㄩ潰涓庡唴閮ㄤ箣闂寸儹閲忎紶閫掔殑鏈虹悊,鎻愬嚭浜嗕竴濂楁?zhèn)�绱㈡ˉ涓葷紗娓╁害鍦虹殑鏅�椋?

本文編號：1463449