【摘要】：簡支梁橋的橋面連續(xù)構造可以有效地改善行車的平順性提高橋梁的整體性能,因而在中小跨徑橋梁中被廣泛采用。然而在后期的運營過程中發(fā)現(xiàn)帶有橋面連續(xù)構造的簡支梁橋在橋面連續(xù)段尤其是連續(xù)縫處鋪裝層的表面產(chǎn)生了橫橋向的貫通裂縫,有的甚至會形成坑槽,影響正常行車;同時橋面連續(xù)構造在設計時并不經(jīng)過專門的分析計算而只通過一定的配筋來控制,隨意性較大。因此研究橋面連續(xù)構造產(chǎn)生裂縫的原因并提出改善措施具有重要的理論和實際應用價值。首先,以中小跨徑公路橋梁中常用的簡支板橋作為研究對象,針對橋面連續(xù)構造在使用過程中易開裂的現(xiàn)象,對其在荷載作用下橋面連續(xù)構造的受力機理進行了彈性分析,導出了其應力的解析表達式。利用有限元分析軟件建立了兩跨橋面連續(xù)的簡支空心板橋,對八種工況下橋面連續(xù)構造的混凝土和鋼筋的應力進行了線彈性分析,并重點針對上緣開裂的現(xiàn)象進行了材料非線性的分析,分析了開裂后鋪裝層內鋼筋的應力并估算裂縫寬度。其次,在考慮車橋耦合振動的基礎上對此類橋梁進行了動力特性分析,給出了帶有橋面連續(xù)構造的簡支板橋和普通簡支板橋的跨中的撓度時程曲線及連續(xù)縫處的彎矩時程曲線,計算了跨中的撓度動力放大系數(shù)和連續(xù)縫處的彎矩動力放大系數(shù)。最后,結合靜動力的分析結果,利用導出的橋面連續(xù)段應力的解析式提出了相應的改進措施。研究結果表明:橋面連續(xù)構造在荷載作用下連續(xù)縫處的上、下緣的混凝土應力都超過了其抗拉極限強度而開裂;車橋耦合振動對連續(xù)縫處混凝土的裂縫開展也較為不利;采用低彈模材料或者粘貼鋼板能夠改善橋面連續(xù)的受力和裂縫擴展的情況,使用碳纖維板材及橋面連續(xù)段張拉預應力的方法效果不佳。研究結果可為橋面連續(xù)簡支梁橋的評價及加固工程應用提供參考。
[Abstract]:The continuous construction of the deck of simply supported beam bridge can effectively improve the ride comfort and improve the overall performance of the bridge, so it is widely used in medium and small span bridges. However, in the later period of operation, it was found that the simple supported beam bridge with continuous structure of the bridge deck produced transversal cracks on the surface of the pavement layer in the continuous section of the bridge deck, especially at the continuous joint, and some even formed potholes, which affected the normal running of the bridge. At the same time, the continuous structure of bridge deck is controlled by reinforcement without special analysis and calculation. Therefore, it is of great theoretical and practical value to study the causes of cracks in continuous structure of bridge deck and to put forward improvement measures. Firstly, the simple supported plate bridge, which is commonly used in medium and small span highway bridges, is taken as the research object, and the stress mechanism of continuous deck structure under load is analyzed according to the phenomenon that the continuous structure of bridge deck is prone to crack in the course of using. An analytical expression of the stress is derived. A simple supported hollow slab bridge with two spans continuous deck is established by using finite element analysis software. The stress of concrete and reinforcement continuously constructed on the deck under eight working conditions is analyzed with linear elasticity. The material nonlinearity of cracking in the upper edge is analyzed, the stress of steel bar in the pavement after cracking is analyzed and the crack width is estimated. Secondly, on the basis of considering the vehicle-bridge coupling vibration, the dynamic characteristics of this kind of bridge are analyzed, and the deflection time history curve and the moment history curve at the continuous joint of the simply supported plate bridge and the common simply supported plate bridge with continuous deck are given. The dynamic magnification factor of deflection in span and the dynamic magnification factor of bending moment at continuous joint are calculated. Finally, combined with the static and dynamic analysis results, the corresponding improvement measures are put forward by using the derived analytical formula of the continuous section stress of the bridge deck. The results show that the concrete stress at the upper and lower edge of the continuous structure of the bridge deck under load exceeds its ultimate tensile strength, and the vehicle-bridge coupling vibration is also unfavorable to the crack development of the concrete in the continuous joint. Using low elastic modulus material or sticking steel plate can improve the continuous force and crack propagation of bridge deck, and the method of using carbon fiber sheet and continuous section of bridge deck tensioning prestress is not effective. The results can be used as reference for evaluation and application of continuous simply supported bridge.
【學位授予單位】：長安大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：U443.31;U445.7

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