CFRP加固混凝土箱梁日照溫度效應(yīng)研究
發(fā)布時(shí)間：2018-11-22 10:10
【摘要】：在過去，國(guó)內(nèi)外研究者對(duì)加固混凝土結(jié)構(gòu)和構(gòu)件的力學(xué)及使用性能進(jìn)行了大量的試驗(yàn)研究與理論分析，已取得了豐碩的研究成果。由于應(yīng)用廣泛的箱形梁橋出現(xiàn)得較晚，其加固實(shí)例還比較少，隨著時(shí)間的推移，早期修建的箱形梁橋?qū)⑾嗬^進(jìn)入服役后期，加固問題必定會(huì)提到議事日程上來。混凝土為熱的不良導(dǎo)體，當(dāng)外部環(huán)境出現(xiàn)較大的溫度變化時(shí)，混凝土結(jié)構(gòu)內(nèi)外會(huì)出現(xiàn)較大的溫差，從而導(dǎo)致較大溫差應(yīng)力的出現(xiàn)。CFRP具有不同于混凝土的熱物性參數(shù)，因此CFRP的外部粘貼使原混凝土箱梁溫度場(chǎng)發(fā)生改變，同時(shí)當(dāng)溫度變化時(shí)，CFRP-混凝土組合結(jié)構(gòu)中應(yīng)力和變形等性能也將發(fā)生改變。故對(duì)CFRP加固混凝土箱梁的日照溫度效應(yīng)的研究是非常有必要的。 本文進(jìn)行了CFRP加固混凝土箱梁日照輻射作用下溫度場(chǎng)及溫度應(yīng)力的試驗(yàn)研究。制作了三片試驗(yàn)梁，三片試驗(yàn)梁均為鋼筋混凝土箱梁，具有相同的幾何尺寸，梁長(zhǎng)3200mm，，橫截面高400mm，寬600mm，頂?shù)装搴穸染鶠?0mm，腹板厚60mm。在梁體L/4截面布置溫度傳感器，在跨中截面布置應(yīng)變片。第一片梁不進(jìn)行CFRP加固，對(duì)其余兩片梁進(jìn)行不同方式的CFRP加固，分別為底面單層加固與U型加固。使用保溫材料，采用不同的遮陰方式模擬出三種不同的日照工況，同種工況測(cè)試三天，分別獲得了各試驗(yàn)梁在不同工況作用下的溫度場(chǎng)及溫度應(yīng)力數(shù)據(jù)，進(jìn)行了初步的分析和探討。 使用ANSYS軟件對(duì)CFRP加固混凝土箱梁的日照溫度試驗(yàn)進(jìn)行有限元模擬，將實(shí)測(cè)數(shù)據(jù)作為初始條件，結(jié)合氣象學(xué)及大氣天文學(xué)的知識(shí)計(jì)算出邊界條件，以數(shù)組的形式施加給有限元模型，求得各試驗(yàn)梁在不同時(shí)刻的溫度場(chǎng)；直接將已求得的溫度場(chǎng)施加給箱梁模型，計(jì)算出各試驗(yàn)梁的溫度應(yīng)力；將實(shí)測(cè)數(shù)據(jù)與有限元模擬的數(shù)據(jù)進(jìn)行對(duì)比分析。 經(jīng)過對(duì)實(shí)測(cè)數(shù)據(jù)與有限元模擬數(shù)據(jù)的綜合分析最終得出；日照輻射作用下，箱梁頂板測(cè)點(diǎn)溫度最高值出現(xiàn)在下午15時(shí)~16時(shí)，而沿高度方向最大溫差出現(xiàn)在下午14時(shí)~16時(shí)。在箱梁同一截面，隨著高度的下降，溫度場(chǎng)時(shí)變規(guī)律有明顯的延遲現(xiàn)象，不同高度測(cè)點(diǎn)溫度時(shí)變曲線每天有兩次交叉點(diǎn)，此時(shí)基本不存在溫度梯度，箱梁整體溫度基本趨于一致；CFRP的粘貼改變了箱梁表面的太陽(yáng)輻射吸收率，與同等條件下未粘貼CFRP的混凝土表面相比，其表面最高溫度高出4~5℃，最終導(dǎo)致了箱梁截面豎向溫差增大；不同日照輻射條件作用對(duì)CFRP加固混凝土箱梁的豎向溫度梯度存在一定的影響，當(dāng)箱梁腹板位置直接承受日照輻射作用時(shí)，其豎向溫度梯度發(fā)生較大變化，尤其當(dāng)腹板表面粘貼有CFRP時(shí)，這種影響體現(xiàn)的更加明顯；未經(jīng)CFRP加固的混凝土箱梁在日照溫度荷載作用下，其頂板大部受拉應(yīng)力作用，部分受壓應(yīng)力作用，底板基本受拉應(yīng)力作用，最大拉應(yīng)力出現(xiàn)在頂板下側(cè)。在頂面粘貼CFRP后，頂板承受溫度應(yīng)力全為受壓，底板拉應(yīng)力大于未加固箱梁的底板拉應(yīng)力。
[Abstract]:In the past, the research and theoretical analysis of the mechanics and performance of the reinforced concrete structures and components by the researchers at home and abroad have made great achievements. Because of the late appearance of the wide box-beam bridge, the reinforcement of the box-beam bridge is less, and with the passage of time, the early-built box-beam bridge will enter the later stage of service, and the reinforcement problem will certainly be put on the agenda. The concrete is a hot bad conductor, and when the external environment has a large temperature change, a large temperature difference occurs inside and outside the concrete structure, leading to the occurrence of large temperature difference stress. The CFRP has a different thermal physical property than that of the concrete, so the external bonding of the CFRP changes the temperature field of the original concrete box girder, and the stress and deformation in the CFRP-concrete composite structure will also change when the temperature is changed. Therefore, it is necessary to study the solar temperature effect of the CFRP-reinforced concrete box girder. The experiment of temperature field and temperature stress under the action of the solar radiation of CFRP-reinforced concrete box girder is carried out in this paper The three test beams are produced. The three test beams are reinforced concrete box beams with the same geometrical dimensions. The beam length is 3200mm, the cross section is 400mm, the width is 600mm, the thickness of the top base plate is 80mm, and the thickness of the web is 60. mm. The temperature sensor is arranged in the section of the beam body L/ 4, and the cross-section arrangement shall be The first beam is not reinforced with CFRP, and the other two beams are reinforced with CFRP in different ways, which are single-layer and U-shaped on the bottom surface, respectively. The temperature field and temperature stress data of each test beam under different working conditions were obtained by using different shading methods, and the preliminary analysis was carried out. In this paper, the method of ANSYS software is used to simulate the sunshine temperature of the reinforced concrete box girder with CFRP, and the measured data is used as the initial condition, and the boundary condition is calculated by the knowledge of meteorology and atmospheric astronomy, and is applied to the form of an array. The finite element model is used to obtain the temperature field of each test beam at different time points, and the temperature field obtained is directly applied to the box girder model, and the temperature stress of each test beam is calculated; and the measured data and the data of the finite element simulation are The results of the comprehensive analysis of the measured data and the finite element simulation data are as follows: the maximum temperature of the top plate of the box girder under the action of solar radiation is at 15: 15 to 16, while the maximum temperature difference in the height direction appears below In the same section of box girder, the time-varying curve of temperature field has obvious delay in the same section of box girder. The temperature-varying curve of different height measuring points has two cross points every day. At this time, there is basically no temperature gradient, and the whole box girder the temperature is basically consistent; the bonding of the CFRP changes the solar radiation absorption rate on the surface of the box girder, and the maximum temperature of the surface of the concrete is 4-5 DEG C compared with the surface of the concrete which is not pasted with the CFRP under the same conditions, and finally the box girder The vertical temperature difference of the cross-section is increased; the effect of different sunshine radiation conditions on the vertical temperature gradient of the CFRP-reinforced concrete box girder has a certain effect, and when the position of the box girder web is directly subjected to the solar radiation action, the vertical temperature gradient of the box girder is greatly changed, especially when the surface of the web plate The effect of this effect is more obvious when the CFRP is pasted; under the action of the sunshine temperature load, the top plate of the reinforced concrete box girder under the action of sunshine temperature is subjected to tensile stress, the part of the top plate is subjected to compressive stress, the bottom plate is basically subjected to tensile stress, and the maximum tensile stress The force appears on the lower side of the top plate. After the CFRP is attached to the top surface, the top plate is subjected to temperature stress all under pressure, and the tensile stress of the bottom plate is greater than that of the non-reinforcement.
【學(xué)位授予單位】：蘭州交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：U441.5;U445.72
本文編號(hào)：2348988
[Abstract]:In the past, the research and theoretical analysis of the mechanics and performance of the reinforced concrete structures and components by the researchers at home and abroad have made great achievements. Because of the late appearance of the wide box-beam bridge, the reinforcement of the box-beam bridge is less, and with the passage of time, the early-built box-beam bridge will enter the later stage of service, and the reinforcement problem will certainly be put on the agenda. The concrete is a hot bad conductor, and when the external environment has a large temperature change, a large temperature difference occurs inside and outside the concrete structure, leading to the occurrence of large temperature difference stress. The CFRP has a different thermal physical property than that of the concrete, so the external bonding of the CFRP changes the temperature field of the original concrete box girder, and the stress and deformation in the CFRP-concrete composite structure will also change when the temperature is changed. Therefore, it is necessary to study the solar temperature effect of the CFRP-reinforced concrete box girder. The experiment of temperature field and temperature stress under the action of the solar radiation of CFRP-reinforced concrete box girder is carried out in this paper The three test beams are produced. The three test beams are reinforced concrete box beams with the same geometrical dimensions. The beam length is 3200mm, the cross section is 400mm, the width is 600mm, the thickness of the top base plate is 80mm, and the thickness of the web is 60. mm. The temperature sensor is arranged in the section of the beam body L/ 4, and the cross-section arrangement shall be The first beam is not reinforced with CFRP, and the other two beams are reinforced with CFRP in different ways, which are single-layer and U-shaped on the bottom surface, respectively. The temperature field and temperature stress data of each test beam under different working conditions were obtained by using different shading methods, and the preliminary analysis was carried out. In this paper, the method of ANSYS software is used to simulate the sunshine temperature of the reinforced concrete box girder with CFRP, and the measured data is used as the initial condition, and the boundary condition is calculated by the knowledge of meteorology and atmospheric astronomy, and is applied to the form of an array. The finite element model is used to obtain the temperature field of each test beam at different time points, and the temperature field obtained is directly applied to the box girder model, and the temperature stress of each test beam is calculated; and the measured data and the data of the finite element simulation are The results of the comprehensive analysis of the measured data and the finite element simulation data are as follows: the maximum temperature of the top plate of the box girder under the action of solar radiation is at 15: 15 to 16, while the maximum temperature difference in the height direction appears below In the same section of box girder, the time-varying curve of temperature field has obvious delay in the same section of box girder. The temperature-varying curve of different height measuring points has two cross points every day. At this time, there is basically no temperature gradient, and the whole box girder the temperature is basically consistent; the bonding of the CFRP changes the solar radiation absorption rate on the surface of the box girder, and the maximum temperature of the surface of the concrete is 4-5 DEG C compared with the surface of the concrete which is not pasted with the CFRP under the same conditions, and finally the box girder The vertical temperature difference of the cross-section is increased; the effect of different sunshine radiation conditions on the vertical temperature gradient of the CFRP-reinforced concrete box girder has a certain effect, and when the position of the box girder web is directly subjected to the solar radiation action, the vertical temperature gradient of the box girder is greatly changed, especially when the surface of the web plate The effect of this effect is more obvious when the CFRP is pasted; under the action of the sunshine temperature load, the top plate of the reinforced concrete box girder under the action of sunshine temperature is subjected to tensile stress, the part of the top plate is subjected to compressive stress, the bottom plate is basically subjected to tensile stress, and the maximum tensile stress The force appears on the lower side of the top plate. After the CFRP is attached to the top surface, the top plate is subjected to temperature stress all under pressure, and the tensile stress of the bottom plate is greater than that of the non-reinforcement.
【學(xué)位授予單位】：蘭州交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：U441.5;U445.72
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