双边箱主梁拱塔斜拉桥剪力滞效应及施工控制研究
发布时间：2018-08-01 17:43
【摘要】：马鞍山长江公路大桥右汉斜拉桥为国内三个主塔首次同时采用的拱形混凝土桥塔的斜拉桥,此种桥型采用塔梁同步的施工方案在国内尚属首次,现阶段并没有相关的资料可供参考,同时此桥的主梁为宽度达到了35.3m宽的双边箱梁,国内针对此类桥梁的剪力滞效应及施工控制方面的研究较少,本文以其为工程背景,主要研究内容和成果如下：(1)利用MIDAS软件建立了桥塔施工的空间有限元模型,分析了主塔的受力和变形情况,通过计算及实测结果可知,塔梁同步施工与非塔梁同步施工方案相比,施工过程中桥塔横桥向外侧最大拉应力及桥塔横桥向位移有所增大,但幅度有限,桥塔横桥向最大拉应力在安全范围内,塔梁同步施工方案对结构虽有一定的不利影响,但可行。在塔梁同步施工过程中,通过参数分析,确定塔梁同步施工过程中的主动水平力施加位置和大小,改善了桥塔受力。(2)采用ANSYS软件建立了主梁局部模型,通过参数分析可知,双边箱主梁顶板厚度增加5cm会使顶板平均压应力减少,底板平均压应力增大,顶板厚度减少5cm对主梁顶板和底板的平均应力影响较小。顶板厚度减少5cm将使顶板由正剪力滞效应转变为负剪力滞效应。主梁竖腹板厚度增加或减少5cm对主梁顶、底板剪力滞效应影响有限。设置横隔板将使主梁正应力分布更均匀,降低剪力滞系数峰值。(3)主梁悬臂施工过程中,已经张拉完成的斜拉索索力同其后7个梁段施工关系密切,之后节段的施工对其影响较小。实测的索力比理论索力略大一些,这同实际施工过程中的临时荷载过多,超重有关。(4)主梁悬臂施工过程中现场分析主梁标高及索力产生误差的原因并修正计算模型,同时将同主梁标高相关的信息作为输入样本,将施工完的标高误差作为输出数据,并采用MATLAB神经网络工具箱实现改进型的BP神经网络,将输入数据同数据之间进行训练,建立联系,得到一个相关的模型进行线形预测分析,通过与实测数据进行对比分析,验证了其正确性,并将预测结果反馈到了主梁立模标高上,最终实现了全桥顺利合拢且主梁线形流畅,斜拉索、主梁和桥塔受力合理,桥塔偏位正常,桥体结构安全可靠。
[Abstract]:The right Han Cable-Stayed Bridge of Ma'anshan Changjiang River Highway Bridge is the first cable-stayed bridge of arch concrete tower adopted simultaneously by three main towers in our country. At the present stage, there is no relevant data for reference. Meanwhile, the main girder of this bridge is a bilateral box girder with a width of 35.3m wide. There are few researches on the shear lag effect and construction control of this kind of bridge in China. This paper takes it as the engineering background. The main research contents and results are as follows: (1) the spatial finite element model of bridge tower construction is established by using MIDAS software, and the stress and deformation of the main tower are analyzed. Compared with the non-tower beam synchronous construction scheme, the maximum tensile stress and the lateral displacement of the tower transverse bridge are increased in the construction process, but the amplitude is limited, and the maximum tensile stress of the tower transverse bridge is in the safe range. The synchronous construction scheme of tower and beam has some adverse effects on the structure, but it is feasible. In the process of tower beam synchronous construction, the position and magnitude of active horizontal force applied in the process of tower beam synchronous construction are determined through parameter analysis. (2) the local model of main beam is established by using ANSYS software, and the parameter analysis shows that, The average compressive stress of the roof and the average compressive stress of the bottom plate increase with the increase of the thickness of the roof of the two-sided box main girder, and the decrease of the thickness of the roof 5cm has little effect on the average stress of the roof and the floor of the main beam. The thickness of the roof will change from the positive shear lag effect to the negative shear lag effect when the thickness of the roof is reduced by 5cm. The increase or decrease of the thickness of the vertical web of the main beam has a limited effect on the shear lag effect of the top and bottom of the main beam. The installation of the transverse diaphragm will make the normal stress distribution of the main beam more uniform and reduce the peak value of the shear lag coefficient. (3) during the construction of the cantilever of the main beam, the cable force that has already been tensioned is closely related to the construction of the following seven sections of beams. The construction of the subsequent segment has little effect on it. The measured cable force is slightly larger than the theoretical cable force, which is related to the excessive temporary load and overweight in the actual construction process. (4) the causes of the errors in the elevation and cable force of the main girder are analyzed on the spot during the construction of the cantilever of the main beam and the calculation model is revised. At the same time, the information related to the elevation of the main beam is taken as the input sample, the elevation error of the finished construction is taken as the output data, and the improved BP neural network is realized by using the MATLAB neural network toolbox, and the input data is trained between the input data and the data. A relative model is obtained for linear prediction and analysis. The correctness of the model is verified by comparing it with the measured data, and the prediction results are fed back to the elevation of the main beam. Finally, the bridge is closed smoothly, the main beam is linear smooth, the stay cable, the main beam and the bridge tower force is reasonable, the bridge tower is in normal position, and the bridge structure is safe and reliable.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U445.4;U448.27
，
本文编号：2158348
[Abstract]:The right Han Cable-Stayed Bridge of Ma'anshan Changjiang River Highway Bridge is the first cable-stayed bridge of arch concrete tower adopted simultaneously by three main towers in our country. At the present stage, there is no relevant data for reference. Meanwhile, the main girder of this bridge is a bilateral box girder with a width of 35.3m wide. There are few researches on the shear lag effect and construction control of this kind of bridge in China. This paper takes it as the engineering background. The main research contents and results are as follows: (1) the spatial finite element model of bridge tower construction is established by using MIDAS software, and the stress and deformation of the main tower are analyzed. Compared with the non-tower beam synchronous construction scheme, the maximum tensile stress and the lateral displacement of the tower transverse bridge are increased in the construction process, but the amplitude is limited, and the maximum tensile stress of the tower transverse bridge is in the safe range. The synchronous construction scheme of tower and beam has some adverse effects on the structure, but it is feasible. In the process of tower beam synchronous construction, the position and magnitude of active horizontal force applied in the process of tower beam synchronous construction are determined through parameter analysis. (2) the local model of main beam is established by using ANSYS software, and the parameter analysis shows that, The average compressive stress of the roof and the average compressive stress of the bottom plate increase with the increase of the thickness of the roof of the two-sided box main girder, and the decrease of the thickness of the roof 5cm has little effect on the average stress of the roof and the floor of the main beam. The thickness of the roof will change from the positive shear lag effect to the negative shear lag effect when the thickness of the roof is reduced by 5cm. The increase or decrease of the thickness of the vertical web of the main beam has a limited effect on the shear lag effect of the top and bottom of the main beam. The installation of the transverse diaphragm will make the normal stress distribution of the main beam more uniform and reduce the peak value of the shear lag coefficient. (3) during the construction of the cantilever of the main beam, the cable force that has already been tensioned is closely related to the construction of the following seven sections of beams. The construction of the subsequent segment has little effect on it. The measured cable force is slightly larger than the theoretical cable force, which is related to the excessive temporary load and overweight in the actual construction process. (4) the causes of the errors in the elevation and cable force of the main girder are analyzed on the spot during the construction of the cantilever of the main beam and the calculation model is revised. At the same time, the information related to the elevation of the main beam is taken as the input sample, the elevation error of the finished construction is taken as the output data, and the improved BP neural network is realized by using the MATLAB neural network toolbox, and the input data is trained between the input data and the data. A relative model is obtained for linear prediction and analysis. The correctness of the model is verified by comparing it with the measured data, and the prediction results are fed back to the elevation of the main beam. Finally, the bridge is closed smoothly, the main beam is linear smooth, the stay cable, the main beam and the bridge tower force is reasonable, the bridge tower is in normal position, and the bridge structure is safe and reliable.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U445.4;U448.27
，
本文编号：2158348
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