發(fā)布時間：2018-01-17 23:31

  本文關(guān)鍵詞：預應(yīng)力混凝土連續(xù)箱梁橋施工中臨時中支墩垮塌對主梁的影響及對策研究　出處：《長安大學》2014年碩士論文　論文類型：學位論文

  更多相關(guān)文章： 連續(xù)梁 裂縫 預應(yīng)力鋼筋 拉應(yīng)力 撓度

【摘要】：預應(yīng)力混凝土連續(xù)箱梁橋以受力合理、結(jié)構(gòu)剛度大、行車平順性好、造型美觀和養(yǎng)護簡單等特點，成為被廣泛應(yīng)用的橋型之一。但這種橋型在施工中，往往會因為施工方式、施工過程中自然災害等因素的影響導致主梁出現(xiàn)裂縫，這嚴重影響了橋梁的使用性和耐久性。因此研究橋梁施工時出現(xiàn)裂縫后的應(yīng)對措施對橋梁的使用性和耐久性有重要意義。 本文以采用支架整體現(xiàn)澆法施工的甘肅某橋為例，通過ANSYS建立三維實體模型，研究了采取不同頂推截面數(shù)、不同頂推力、預先張拉不同位置的預應(yīng)力鋼筋和不同預應(yīng)力大小、以及粘貼不同厚度鋼板和不同厚度碳纖維的應(yīng)對措施對中跨主梁的受力影響，主要成果如下： （1）隨著中跨主梁貝雷梁臨時支架下頂推截面數(shù)的增加，，主梁的最大拉應(yīng)力在不斷減小，并且承受較大拉應(yīng)力的區(qū)域也在不斷縮小。 （2）中跨臨時中支墩處頂推力對主梁的受力有明顯的影響，在一定范圍內(nèi)，隨著頂推力的不斷增加，中跨主梁的最大撓度值和最大拉應(yīng)力值在都不斷減小。 （3）當采取張拉單根預應(yīng)力鋼筋的應(yīng)對措施時，越是張拉遠離底板位置處的預應(yīng)力鋼筋，主梁腹板位置處的最大拉應(yīng)力和撓度減小的越明顯；而采取同時張拉所有預應(yīng)力鋼筋的應(yīng)對措施時，對主梁的強度和剛度產(chǎn)生的效果明顯優(yōu)于采取單獨張拉任何位置處預應(yīng)力鋼筋產(chǎn)生的效果；隨著張拉預應(yīng)力的增加，主梁的最大拉應(yīng)力值和最大撓度值在不斷減小。 （4）采取粘貼鋼板和粘貼碳纖維的應(yīng)對措施對主梁的撓度和應(yīng)力幾乎沒有改善，效果不明顯。 （5）當中跨臨時中支墩處頂推力為250t，并且張拉所有預應(yīng)力鋼筋50%預應(yīng)力時，該橋的強度和剛度都得到了較好的改善。
[Abstract]:Prestressed concrete continuous box girder bridge is one of the widely used bridges because of its reasonable force, large structure stiffness, good ride comfort, beautiful shape and simple maintenance. Often because of the construction mode, construction process of natural disasters and other factors resulting in cracks in the main beam. Therefore, it is of great significance to study the measures to deal with the cracks in the construction of bridges, which is of great significance to the use and durability of the bridges. In this paper, a bridge in Gansu Province which is constructed with support monolithic cast-in-place method is taken as an example. The three-dimensional solid model is established by ANSYS, and the different pushing cross sections and different top thrust are studied. The main results are as follows: (1) the effects of pre-tensioning different positions of prestressed steel bar and different prestressing force size, as well as different thickness of steel plate and different thickness of carbon fiber on the stress of the mid-span main beam are as follows: 1) with the increase of the number of pushing sections under the temporary support of Beilai beam with medium span, the maximum tensile stress of the main beam is decreasing continuously, and the region bearing the larger tensile stress is also shrinking. The top thrust of intermediate span temporary middle pier has obvious influence on the force of the main beam, and in a certain range, with the increasing of the top thrust. The maximum deflection value and the maximum tensile stress value of the middle span main beam are both decreasing. 3) the more the prestressed steel bar far away from the bottom plate is tensioned, the more obvious the maximum tensile stress and deflection of the main girder web are reduced when the measures are taken. The effect on the strength and stiffness of the main beam is obviously better than that of the prestressed steel bar at any position of the single tensioning when the corresponding measures are taken to stretch all the prestressed steel bars at the same time. With the increase of tensioning prestress, the maximum tensile stress and maximum deflection of the main beam are decreasing. 4) the deflection and stress of the main beam are hardly improved by the measures of sticking steel plate and carbon fiber, and the effect is not obvious. The strength and stiffness of the bridge are improved better when the top thrust is 250 t and 50% prestressing bar is tensioned.
【學位授予單位】：長安大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U448.35;U445.7

【參考文獻】

相關(guān)期刊論文 前5條

1 林小楊,李志能;普通鋼筋混凝土連續(xù)箱梁裂縫分析[J];中外公路;2002年04期

2 張元海;李喬;;預應(yīng)力混凝土連續(xù)箱梁橋的溫度應(yīng)力分析[J];土木工程學報;2006年03期

3 劉來君;大跨徑橋梁施工控制溫度荷載[J];長安大學學報(自然科學版);2003年02期

4 李方東;預應(yīng)力砼連續(xù)箱梁橋常見裂縫成因分析[J];公路與汽運;2004年03期

5 張軍營;;粘貼碳纖維板工藝在混凝土橋梁加固工程中的應(yīng)用[J];科技創(chuàng)新導報;2008年05期

本文編號：1438482