预应力混凝土连续梁的施工监控与剪力滞效应研究

发布时间：2018-01-07 04:15

本文关键词：预应力混凝土连续梁的施工监控与剪力滞效应研究　出处：《兰州交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：近年来,随着高速铁路、公路建设的快速发展,宽跨度单幅单箱室梁越来越多的应用到预应力连续梁桥、连续刚构桥建设中,桥梁跨径及翼缘宽度的增大剪力滞效应越来越明显,不可忽略。本文以宝兰客专锦屏牛谷河大桥为工程背景,结合变高度连续刚构桥悬臂浇注的施工方法,研究在施工过程中各阶段在恒载及预应力作用下截面的剪力滞效应。在进行施工阶段分析时,本文运用ANSYS和MIDAS软件模拟悬臂施工全过程,并通过对该桥施工进行监控控制,提出一些施工过程控制和连续梁设计的理论和建议。重力恒载作用下宽跨比越大,未施加横向预应力,剪力滞效应更明显,而腹板厚度变化则对该效应影响不甚明显。在重力和预应力作用下,悬臂施工阶段在其刚浇注时剪力滞效应最大,随着浇注阶段的增加剪力滞效应呈现递减规律。悬臂施工体系转换过程中,各个截面应力及剪力滞变化比较复杂,中跨各个截面处剪力滞效应变化最大;墩柱处截面顶板压应力变大,剪力滞效应变化微小,顶板中间有负剪力滞效应,翼缘板两边正剪力滞效应明显;边跨截面在前三个过程中应力和剪力滞基本无明显变化,边跨合拢后压应力值减小,负剪力滞效应增大在施工阶段随着连续梁桥的结构和荷载状态的不断变化,结构内力和变形随之不断发生变化。通过现场实际监控数据得知,在连续梁桥悬臂浇筑施工过程中,其主梁挠度较大,由于设计时所采用参数,与实际工程中所表现出来的参数不完全一致,使得实际结构的每一状态未必能达到设计值,根据施工中结构的实测值对主要设计参数进行估计,逐步修正设计值,重新给出施工中挠度的理论期望值,消除理论值与实测值的不一致的主要部分,采用一定的方法和手段对结构变形、应力加以控制,以确保施工得以安全、准确实施。在此有限元分析基础上,对箱梁剪力滞效应在施工过程中的截面几何影响因素、预应力因素以及体系变换进行了计算分析,并对桥梁施工过程中以及设计中的相关问题提出了相关建议,研究结果对箱梁桥设计有一定的研究价值。
[Abstract]:In recent years, with the rapid development of high-speed railway and highway construction, the wide span single box box beam is more and more used in the construction of prestressed continuous beam bridge and continuous rigid frame bridge. The shear lag effect of bridge span and flange width is more and more obvious, which can not be ignored. This paper takes Baolanke special Jinping Niu Gu River Bridge as the engineering background, combined with the construction method of cantilever pouring of variable height continuous rigid frame bridge. The shear lag effect of section under dead load and prestress in each stage of construction is studied. In the analysis of construction stage, ANSYS and MIDAS software are used to simulate the whole process of cantilever construction. Through monitoring and controlling the construction of the bridge, some theories and suggestions of construction process control and continuous beam design are put forward. The wider span ratio is increased under the action of gravity dead load, the shear lag effect is more obvious without applying transverse prestress. Under the action of gravity and prestress, the shear lag effect of cantilever construction stage is the biggest when it is just poured. The shear lag effect decreases with the increase of pouring stage. During the transition of cantilever construction system, the variation of stress and shear lag of each section is more complex, and the shear lag effect at each cross section of middle span is the biggest. At the pier column, the compressive stress of the section roof becomes larger, the shear lag effect changes slightly, the negative shear lag effect exists in the middle of the roof plate, and the positive shear lag effect on both sides of the flange plate is obvious. The stress and shear lag of the side span cross section in the first three processes have no obvious change, the compressive stress value decreases after the side span is closed, and the negative shear lag effect increases with the continuous change of the structure and load state of the continuous beam bridge in the construction stage. The internal force and deformation of the structure change constantly. According to the field monitoring data, the deflection of the main beam is larger during the construction of cantilever of continuous beam bridge, because of the parameters used in the design. Because of the inconsistency with the actual engineering parameters, each state of the actual structure may not reach the design value, and the main design parameters are estimated according to the measured value of the structure in construction. The design value is revised step by step, the theoretical expected value of deflection in construction is given again, the main part of the inconsistency between the theoretical value and the measured value is eliminated, and some methods and means are used to control the deformation and stress of the structure. On the basis of the finite element analysis, the influence factors of section geometry, prestressing force and system transformation of box girder shear lag effect in construction process are calculated and analyzed. Some suggestions are put forward for the bridge construction and design, and the results are valuable to the design of box girder bridge.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U445.57

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