本文選題：既有結構 + 可靠度　； 參考：《清華大學》2015年碩士論文

【摘要】：既有結構在服役過程中,碰撞損傷、介質侵蝕等原因會導致結構承載能力的降低,從而對其正常服役帶來安全隱患。可靠度分析以概率統(tǒng)計為基礎,著眼于結構在服役過程中的承載能力及荷載的不確定性,是結構安全評價的重要手段。對結構進行可靠度分析,可以得到定量的安全評估結果,進而為結構設計和服役期內的維護措施優(yōu)化提供重要依據(jù)。選取合適的承載能力衰減以及荷載過程模型是結構可靠度分析的基礎。在現(xiàn)有的可靠度研究中,概率模型選取往往基于很多假設;這些假設在簡化問題的同時也帶來了可靠度評估結果與真實情況的差異。本研究主要討論劣化結構時變可靠度分析中的模型改進,具體內容有:(1)考慮荷載隨機過程的相關性對結構時變可靠度的影響,指出:若不考慮荷載過程相關性,會低估結構的可靠度;并且,荷載過程相關性越大,低估的效果越明顯。(2)研究了荷載的統(tǒng)計參數(shù)(均值、標準差)的時變特性對結構可靠度的影響,并提出了可靠度計算的顯式公式。算例表明:車載隨機過程參數(shù)對結構可靠度的影響顯著。在20年的評估期內,均值每年增加1.1%或標準差每年增加1.3%,都會造成結構的失效概率增大兩倍。(3)以風荷載為例,研究了荷載發(fā)生頻率的時變特性對結構可靠度的影響,并給出了可靠度計算的顯式公式。(4)研究了既有劣化橋梁的服役歷史對結構后續(xù)服役期內的可靠度的更新效果,指出:當車載歷史中包含超載現(xiàn)象或橋梁承載能力明顯劣化時,更新后的可靠度更能反映既有橋梁真實的可靠度水平,而不考慮車載歷史則會明顯低估橋梁的可靠度水平。(5)研究了既有劣化橋梁的服役歷史對結構當前時刻初評承載能力的更新作用,并給出了顯式計算公式。分析表明,車載大小和承載能力衰減程度對可靠度的更新效果有顯著影響。當車載歷史中包含超載現(xiàn)象或橋梁承載能力明顯劣化時,更新后的可靠度更能反映既有橋梁真實的可靠度水平,而不考慮車載歷史則會明顯低估橋梁的可靠度水平。
[Abstract]:During the service of the existing structure, the damage of collision and the erosion of the medium will lead to the decrease of the bearing capacity of the structure, which will bring the hidden danger to the normal service of the existing structure. Reliability analysis, based on probability and statistics, focuses on the bearing capacity and the uncertainty of load in the course of service, which is an important means of structural safety evaluation. By analyzing the reliability of the structure, the quantitative safety evaluation results can be obtained, which can provide an important basis for the structural design and the optimization of maintenance measures during the service period. The selection of appropriate load capacity attenuation and load process model is the basis of structural reliability analysis. In the existing reliability studies, the selection of probabilistic models is often based on many assumptions, which simplify the problem and lead to the difference between the reliability evaluation results and the real situation. The main contents of this study are as follows: (1) considering the influence of the random process of load on the time-varying reliability of the structure, it is pointed out that if the correlation of load process is not considered, The reliability of the structure is underestimated, and the greater the correlation of the load process, the more obvious the effect of underestimation. (2) the influence of the time-varying characteristics of the statistical parameters (mean, standard deviation) of the load on the reliability of the structure is studied. An explicit formula for reliability calculation is presented. An example shows that the parameters of the vehicle random process have a significant effect on the reliability of the structure. During the 20-year evaluation period, the average value increases by 1.1% per year or the standard deviation increases by 1.3% per year, which results in a double failure probability of the structure. (3) taking the wind load as an example, the influence of the time-varying characteristics of the frequency of the load on the reliability of the structure is studied. The explicit formula of reliability calculation is given. (4) the renewal effect of the service history of the existing degraded bridge on the reliability during the subsequent service period of the structure is studied. It is pointed out that when the overloading phenomenon is included in the vehicular history or the bearing capacity of the bridge is obviously degraded, The updated reliability can better reflect the true reliability level of the existing bridges. The reliability level of the bridge is obviously underestimated without considering the history of the vehicle. (5) the renewal of the service history of the existing degraded bridge to the initial assessment of the bearing capacity at the present moment of the structure is studied, and the explicit calculation formula is given. The analysis shows that the vehicle size and the attenuation degree of the bearing capacity have a significant influence on the reliability renewal effect. When the overloading phenomenon is included in the vehicle history or the bearing capacity of the bridge is obviously degraded, the updated reliability can better reflect the true reliability level of the existing bridge, but the reliability level of the bridge will be obviously underestimated without considering the vehicular history.
【學位授予單位】：清華大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TU311.2

【參考文獻】

相關期刊論文 前10條

1 俞登科;李正良;韓楓;汪之松;;基于性能目標的特高壓輸電塔抗風可靠度分析[J];防災減災工程學報;2013年06期

2 黃銘楓;;基于風振性能的高層建筑抗風設計優(yōu)化[J];工程力學;2013年02期

3 趙明偉;顧明;;輕型鋼結構風災易損性概率分析[J];中南大學學報(自然科學版);2012年09期

4 李植淮;李春前;孫健康;李全旺;;基于GPD模型的車輛荷載效應極值估計[J];工程力學;2012年S1期

5 謝強;孫力;林韓;陳強;;500kV輸電桿塔結構抗風極限承載力試驗研究[J];高電壓技術;2012年03期

6 孫曉燕;潘宏;王海龍;王建秀;;大氣環(huán)境下服役公路梁橋結構時變可靠度分析[J];浙江大學學報(工學版);2012年04期

7 趙昕;丁潔民;孫華華;巢斯;;上海中心大廈結構抗風設計[J];建筑結構學報;2011年07期

8 潘鵬;李全旺;周怡斌;李運生;王元清;;某公路大橋車輛荷載調查與局部疲勞分析[J];土木工程學報;2011年05期

9 周彬彬;顧祥林;張偉平;金賢玉;黃慶華;;海洋大氣環(huán)境下鋼筋混凝土梁受彎時變可靠度分析[J];土木工程學報;2010年S2期

10 李全旺;李春前;孫健康;;基于結構可靠性理論的既有橋梁承載能力評估[J];工程力學;2010年S2期

相關博士學位論文 前2條

1 張立業(yè);基于隨機過程的橋梁系統(tǒng)可靠性及其模糊綜合評價研究[D];吉林大學;2013年

2 徐付霞;Copula理論與極值統(tǒng)計的應用[D];天津大學;2008年

相關碩士學位論文 前2條

1 雷旭;在役混凝土橋梁基于風險分析的承載能力評估研究[D];長沙理工大學;2011年

2 鐘曙亮;公路既有橋梁承載力評定方法研究[D];西南交通大學;2010年

，

本文編號：2054998