混凝土T型公路桥梁的温度观测与温度应力分析
发布时间：2018-08-27 15:15
【摘要】：温度作用是公路桥梁设计中需考虑的主要荷载之一,它的分布形式及大小直接关系到桥梁结构的安全性、适用性和耐久性。我国现行的《公路桥涵设计通用规范》JTJD60-2004直接沿用了美国AASHTO规范中关于温度作用计算的规定,未考虑我国地域差异及混凝土铺装层厚度对竖向温度梯度分布及最大温差的影响。为此,本文结合桥梁通用规范修订项目“公路桥梁竖向梯度模型研究”,开展了混凝土T型公路桥梁温度场的观测及温度应力分析。本文主要内容和结论如下： (1)针对温度作用,归纳总结了国内外规范的差异。 (2)制作了50mm、100mm两种不同厚度沥青混凝土和150mm、200mm两种不同厚度素混凝土铺装的混凝土T型梁,从2013年4月起至2014年2月,对8个横断面146个测点的温度进行了连续监测。结果发现,混凝土T型梁横向、纵向温差不大,竖向温差较大,两种铺装层T型梁截面竖向温差分别约为14℃和5℃。与公路桥涵规范相比,本试验沥青混凝土铺装层T型梁的最大温差均低于规定值(分别为20℃和14℃),混凝土铺装层也大大降低了桥梁最大温差值。规范温度梯度模式采用双折线,本试验沥青铺装层试件采用对数函数和双折线分布函数表示,双折线函数的转折点在距离桥面板顶面O.1m的位置处。混凝土铺装层试件采用指数函数和三折线函数描述,三折线函数的转折点分别在距离桥面板顶面0.25m和0.6m的位置处。对每一个单位(10天)的最大温差进行统计,发现全年的日最大温差随时间呈正弦函数变化。 (3)结合温度场有限元理论,利用实测资料及气象资料确定了综合温度、热交换系数等参数及混凝土的热物理性能参数,采用ANSYS有限元软件对混凝土T型梁进行了瞬态温度场的仿真模拟,并与实测值进行了对比。结果表明,温度场的理论计算值与实测值较为接近,且沿竖向走势也基本一致,这说明输入的参数值基本准确。 (4)采用理论公式和有限元软件MIDAS/Civil分别对七种温度梯度模式下的桥梁温度应力进行了计算。结果表明,不同温度梯度模式下桥梁沿梁高的温度应力趋势基本相同,即,梁顶板受压,腹板受拉,梁底受压。翼缘下方0.1m范围内的拉应力偏大,是裂缝产生潜在区域,在工程设计时应该加以注意。
[Abstract]:The effect of temperature is one of the main loads to be considered in the design of highway bridges. Its distribution and size are directly related to the safety, applicability and durability of bridge structures. The current General Code for Design of Highway Bridges and culverts in China JTJD60-2004 directly follows the provisions of the AASHTO Code of the United States on the calculation of temperature effects without considering the influence of regional differences in China and the thickness of concrete pavement on the vertical temperature gradient distribution and maximum temperature difference. In this paper, the temperature field observation and thermal stress analysis of concrete T-type highway bridge are carried out in combination with the project of "study on Vertical gradient Model of Highway Bridge", which is the revision project of general specification for bridges. The main contents and conclusions of this paper are as follows: (1) aiming at the effect of temperature, The differences of specifications at home and abroad are summarized. (2) two kinds of concrete T-beams with different thickness of 50mm / 100mm asphalt concrete and 150mm / 200mm plain concrete with different thickness are made, from April 2013 to February 2014, The temperature of 146 measuring points on 8 cross sections was continuously monitored. The results show that the transverse, longitudinal and vertical temperature difference of T-beam is small, and the vertical temperature difference is about 14 鈩，
本文编号：2207662
[Abstract]:The effect of temperature is one of the main loads to be considered in the design of highway bridges. Its distribution and size are directly related to the safety, applicability and durability of bridge structures. The current General Code for Design of Highway Bridges and culverts in China JTJD60-2004 directly follows the provisions of the AASHTO Code of the United States on the calculation of temperature effects without considering the influence of regional differences in China and the thickness of concrete pavement on the vertical temperature gradient distribution and maximum temperature difference. In this paper, the temperature field observation and thermal stress analysis of concrete T-type highway bridge are carried out in combination with the project of "study on Vertical gradient Model of Highway Bridge", which is the revision project of general specification for bridges. The main contents and conclusions of this paper are as follows: (1) aiming at the effect of temperature, The differences of specifications at home and abroad are summarized. (2) two kinds of concrete T-beams with different thickness of 50mm / 100mm asphalt concrete and 150mm / 200mm plain concrete with different thickness are made, from April 2013 to February 2014, The temperature of 146 measuring points on 8 cross sections was continuously monitored. The results show that the transverse, longitudinal and vertical temperature difference of T-beam is small, and the vertical temperature difference is about 14 鈩，
本文编号：2207662
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