本文選題：轉體施工 + 大體積混凝土承臺　； 參考：《武漢理工大學》2014年碩士論文

【摘要】：隨著我國橋梁建設事業的不斷發展，大跨徑大噸位的橋梁越來越多的采用轉體施工。橋梁轉體施工工藝，在建造過程中本著“轉得動、轉得穩、轉得準”的原則，對轉動體系的施工與監控尤為重要。大噸位轉體橋梁不僅要求施工精良的轉動體系，而且要求體積大、強度高、穩定性好的混凝土承臺。本文以京包鐵路分離式立交橋轉體施工控制和穩定性分析項目為工程背景，選用ANSYS分析軟件對大噸位T構轉體橋承臺進行了抗裂性能分析。主要內容有： (1)分析了大體積混凝土結構早期開裂的主要原因，是水泥水化放熱致使混凝土結構內部產生不均勻拉應力引起的。從而通過對大體積混凝土承臺澆筑后前十天的養護環境模擬，對大體積混凝土承臺進行了溫度場和溫度應力場分析，并通過分析的結果與實測結果對比，驗證了分析方法的可行性。 (2)對比了大體積承臺的兩種主要設計方法：控制截面法和空間桁架模型分析法，對轉體橋承臺施工過程中和轉體就位封裝后，承臺的有效高度發生變化，根據承臺矩厚比，分別對承臺進行了承載能力分析，并對承臺內關鍵受力部位進行了精細化分析。 (3)通過對京包鐵路分離式立交橋轉體施工過程的分析，確定了針對承臺的三個典型工況：稱重試驗前，配重后，封裝后，分別對承臺進行分析計算，得出了承臺的傳力模式和破壞機理。 (4)按照現場隨機振動實測數據，近似轉化成隨機荷載施加在承臺上，，分析了承臺關鍵受力部位在隨機荷載作用下的響應。驗證了轉體橋承臺內鋼轉盤應力并非圓心處最大，而是延半徑方向距圓心2/3R處最大。 (5)參照規范要求，結合現場實測數據，對大體積承臺的溫度抗裂措施提出了建議。并通過分析轉體橋承臺在巨大豎向荷載作用下的傳力模型和破壞機理，提出了轉體橋承臺在荷載作用下的抗裂建議。 研究表明：導致大噸位T型剛構轉體橋承臺開裂的因素主要有溫度應力引起的開裂，和不平衡荷載以及隨機荷載作用下的開裂。根據京包鐵路分離式立交橋轉體橋施工過程分析，證明了稱重試驗前承臺內的應力狀態為最危險狀態。對包含轉動體系的大體積承臺的抗裂性能分析結果提出溫度裂縫以及荷載裂縫的預防措施，對大噸位轉體橋施工特別是承臺的施工提供保障。
[Abstract]:With the continuous development of bridge construction in our country, more and more bridges with long span and large tonnage are constructed with rotary construction.In the process of construction, it is very important for the construction and monitoring of the rotational system to follow the principle of "turning can move, turning steadily and turning accurately".The large tonnage rotary bridge requires not only a well-constructed rotating system, but also a concrete cap with large volume, high strength and good stability.In this paper, based on the construction control and stability analysis project of separated interchange bridge of Beijing-Baotong railway, the anti-crack performance of large-tonnage T-structure rotary bridge cap is analyzed by using ANSYS analysis software.The main contents are:1) the main causes of early cracking of mass concrete structures are analyzed, which are caused by uneven tensile stress in concrete structures caused by hydration and heat release of cement.The temperature field and temperature stress field of mass concrete cap are analyzed by simulating the maintenance environment ten days before pouring, and the results are compared with the measured results.The feasibility of the analytical method is verified.This paper compares two main design methods of mass cap: control section method and spatial truss model analysis method. The effective height of the cap changes during the construction process of the cap of the rotary bridge and after the turning-in package, according to the ratio of the cap moment to the thickness,The bearing capacity of the cap is analyzed, and the key parts of the cap are analyzed in detail.Through the analysis of the construction process of the separated interchange bridge of Jingbao railway, three typical working conditions are determined: before weighing test, after weighing, and after encapsulation, the pile cap is analyzed and calculated separately.The transmission mode and failure mechanism of cap are obtained.4) according to the measured data of random vibration in the field, the response of the key part of the cap subjected to random load is analyzed.It is verified that the stress of the steel turntable in the cap of the rotary bridge is not the largest at the center of the circle, but the maximum at the direction of the extension radius being 2 / 3R from the center of the circle.5) according to the requirements of the specification and the field measured data, some suggestions are put forward for the temperature crack resistance measures of the mass cap.Based on the analysis of the load transfer model and failure mechanism of the turning-bridge cap under the huge vertical load, the paper puts forward the anti-crack suggestion of the turning-bridge cap under the load.The results show that the main factors leading to the cap cracking of the large-tonnage T-type rigid frame rotary bridge are the cracking caused by temperature stress, the unbalance load and the cracking under random load.According to the analysis of the construction process of the rotary bridge of the separated interchange bridge of the Beijing-Bao-Baotong Railway, it is proved that the stress state in the cap before weighing test is the most dangerous state.Based on the analysis of crack resistance of large cap with rotating system, the preventive measures of temperature crack and load crack are put forward, which can provide guarantee for the construction of large tonnage rotary bridge, especially for the construction of pile cap.
【學位授予單位】：武漢理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U443.25

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