【摘要】：T型剛構橋在上世紀后半段一經(jīng)問世,便得到了廣泛應用。隨著運營時間的增長和車輛荷載的長期作用,T型剛構橋容易出現(xiàn)下?lián)�、位移等病�?影響橋梁結構的安全使用。依據(jù)橋梁定期檢查和長期監(jiān)測數(shù)據(jù),對運營期T型剛構的健康狀態(tài)進行評估研究,分析橋梁結構損傷程度,評價橋梁承載能力和安全度,為橋梁的養(yǎng)護和加固維修提供依據(jù),具有一定的理論和和實際工程意義。本文依托廣東某T型剛構橋長期變形監(jiān)測和定期檢測工程,應用MIDAS CIVIL軟件進行有限元建模分析計算,結合橋梁定期檢測、長期變形監(jiān)測和靜載試驗,對運營期橋梁的健康狀態(tài)進行了分析,結果表明:(1)橋梁懸臂端下?lián)吓c掛梁橫向位移兩種病害突出,懸臂端下?lián)系闹饕绊懸蛩赜谢炷潦湛s徐變、預應力損失和溫度效應等,掛梁橫向位移的可能影響因素有牛腿不對稱下?lián)稀⒅ё摽蘸蜋M向荷載作用;(2)混凝土收縮徐變對橋梁撓度的影響與時間有關,下?lián)喜『χ饕l(fā)生在成橋后一年內,隨后逐漸趨于平穩(wěn);預應力損失工況下下?lián)狭颗c預應力損失的系數(shù)大致呈線性相關;升溫作用會在邊跨部位輕微加大橋梁的下?lián)?在主跨部位使橋梁產(chǎn)生大幅的上拱以平衡下?lián)喜『?降溫作用反之亦然;(3)牛腿的不對稱下?lián)蠈炝簷M向位移并不明顯;支座脫空會加大橫向位移,支座脫空一處的影響大于兩處支座脫空;風速越大造成的橋梁橫向位移越大,但從外側而來的風對卻邊跨掛梁外移的病害有利;(4)該橋已安全運營20年,自2007年以來,橋面撓度變化較小,線形平順;定期檢測結果表明存在伸縮縫積砂土、支座輕微脫空、梁體和橋墩混凝土剝落、露筋銹蝕等病害;靜載試驗結果表明目前結構性能均滿足設計要求。本文的分析證明了主橋的撓度變化和掛梁的橫向位移均為多種因素共同作用的結果,雖然監(jiān)測顯示橋梁自加固以來橋梁撓度變化和橫向位移變化均不大,且受力狀態(tài)良好,但仍需繼續(xù)對橋梁進行長期健康監(jiān)測與定期檢查,及時發(fā)現(xiàn)和預測結構病害,確保橋梁安全運營。
[Abstract]:T-shaped rigid frame bridge has been widely used as soon as it came out in the second half of the last century. With the increase of operation time and the long-term effect of vehicle load, T-shaped rigid frame bridge is prone to deflection, displacement and other diseases, which affects the safe use of bridge structure. According to the regular inspection and long-term monitoring data of the bridge, the health state of the T-shaped rigid frame during operation is evaluated and studied, and the damage degree of the bridge structure is analyzed, and the bearing capacity and safety degree of the bridge are evaluated, which provides the basis for the maintenance and reinforcement of the bridge, and has certain theoretical and practical engineering significance. In this paper, based on the long-term deformation monitoring and regular detection project of a T-shaped rigid frame bridge in Guangdong, the finite element modeling and calculation are carried out by using MIDAS CIVIL software. Combined with the regular detection, long-term deformation monitoring and static load test of the bridge, the health state of the bridge during operation is analyzed. The results show that: (1) the two diseases of bridge cantilever end deflection and lateral displacement of hanging beam are prominent, and the main influencing factors of cantilever end deflection are concrete shrinkage and creep. Such as prestress loss and temperature effect, the possible influencing factors of transverse displacement of hanging beam are asymmetrical deflection of cow leg, void of bearing and transverse load. (2) the influence of concrete shrinkage and creep on the deflection of the bridge is related to time, and the deflection disease mainly occurs within one year after the completion of the bridge, and then tends to be stable gradually; under the condition of prestress loss, the coefficient of deflection and prestress loss is approximately linear; the heating effect will slightly increase the deflection of the bridge in the side span, make the bridge produce large arch to balance the deflection disease in the main span, and vice versa; (3) the asymmetrical deflection of cow leg has no obvious effect on the lateral displacement of the hanging beam; the clearance of the bearing will increase the transverse displacement of the hanging beam, and the influence of the emptiness of the bearing will be greater than that of the two supports; the greater the wind speed, the greater the lateral displacement of the bridge, but the wind from the outside is beneficial to the disease of moving out of the hanging beam. (4) the bridge has been safely operated for 20 years. Since 2007, the deflection of the bridge deck has changed little and the alignment has been smooth. The results of periodic test show that there are some diseases, such as sand accumulation of expansion joint, slight void of support, spalling of concrete of beam body and pier, corrosion of exposed tendons, etc. The results of static load test show that the structural performance meets the design requirements at present. The analysis of this paper proves that the deflection change of the main bridge and the transverse displacement of the hanging beam are the results of many factors. Although the monitoring shows that the deflection and lateral displacement of the bridge have little change since reinforcement, and the stress state is good, it is still necessary to continue to carry on the long-term health monitoring and regular inspection of the bridge, detect and predict the structural diseases in time, and ensure the safe operation of the bridge.
【學位授予單位】：華南理工大學
【學位級別】：碩士
【學位授予年份】：2016
【分類號】：U445.7;U448.23
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本文編號：2501300