【摘要】：大跨徑預(yù)應(yīng)力混凝土連續(xù)剛構(gòu)橋憑借其跨越溝壑能力強,能適應(yīng)獨特地形、伸縮縫少,行車舒適性好、上部結(jié)構(gòu)剛度大等優(yōu)點,已經(jīng)在工程界得到了廣泛的應(yīng)用。但隨著服役時間的增長,許多連續(xù)剛構(gòu)橋已經(jīng)出現(xiàn)了非常嚴(yán)重的下?lián)虾烷_裂問題。為了解決上述問題,我們必須對損傷后預(yù)應(yīng)力混凝土連續(xù)剛構(gòu)橋的承載力進(jìn)行研究和探討,并提出有效可行的加固方案。關(guān)于橋梁損傷評估的研究文章較多,但就橋梁整體開裂后對橋梁結(jié)構(gòu)承載力影響程度的研究卻較少,另外就橋梁加固方法而言,最為常用也最為有效的是預(yù)應(yīng)力加固,但預(yù)應(yīng)力需要施加多大最為理想,是橋梁加固設(shè)計的重要內(nèi)容,也是其理論研究的關(guān)鍵。本文以陜西洛河大橋為工程背景,針對上述所提出的問題,做了下面三個方面的研究:1)計算預(yù)應(yīng)力損失多少時橋梁底板下緣出現(xiàn)拉裂應(yīng)力,即采用預(yù)應(yīng)力法加固橋梁時需要施加的預(yù)應(yīng)力控制值。2)分析計算中間跨開裂后對橋梁承載力的影響及全橋開裂后對橋梁承載力的影響程度。3)對比分析中間跨開裂與全橋整體開裂對橋梁結(jié)構(gòu)承載力的影響。研究分析結(jié)果表明:(1)當(dāng)預(yù)應(yīng)力損失達(dá)到23.8%時橋梁已經(jīng)開裂,為了確保結(jié)構(gòu)安全,考慮計算的誤差、并結(jié)合以往加固的一些經(jīng)驗,大跨徑預(yù)應(yīng)力混凝土連續(xù)剛構(gòu)橋預(yù)應(yīng)力損失接近20%時就需加固,加固時所需施加的預(yù)應(yīng)力以原設(shè)計值的20%進(jìn)行控制。(2)就橋梁整體承載能力而言,中間跨開裂后與全橋開裂后,橋梁承載力分別降低了12%和15%。(3)全橋開裂與僅中間跨開裂對橋梁承載能力影響相接近,即對于大跨徑預(yù)應(yīng)力混凝土連續(xù)剛構(gòu)橋來說只要一跨破壞,就標(biāo)志著橋梁已經(jīng)基本破壞。
[Abstract]:The long-span prestressed concrete continuous rigid frame bridge has been widely used in engineering field because of its strong ability to cross the gully, the ability to adapt to the unique terrain, the few expansion joints, the good driving comfort and the large stiffness of the superstructure. However, with the increase of service time, many continuous rigid frame bridges have appeared very serious problems of deflection and cracking. In order to solve the above problems, we must study and discuss the bearing capacity of prestressed concrete continuous rigid frame bridge after damage, and put forward effective and feasible reinforcement scheme. There are many research papers on bridge damage assessment, but there are few studies on the influence of bridge cracking on the bearing capacity of bridge structure. In addition, in terms of bridge strengthening methods, the most commonly used and most effective method is prestressed reinforcement. However, how much prestress needs to be applied is an important content of bridge reinforcement design and the key of its theoretical research. Based on the engineering background of Luohe Bridge in Shaanxi Province, the following three aspects have been studied in this paper: 1) when calculating the loss of prestressing force, there is tensile crack stress at the bottom of the bridge. That is, the pre-stress control value needed to be applied in the reinforcement of bridge by prestressed method. 2) the influence of cracking of intermediate span on the bearing capacity of bridge and the degree of influence on bearing capacity of bridge after cracking of whole bridge are analyzed and calculated. 3) in the comparative analysis, The influence of interspan cracking and whole bridge cracking on the bearing capacity of bridge structure. The results show that: (1) the bridge has cracked when the prestress loss reaches 23.8. in order to ensure the safety of the structure, the calculation error is considered. The prestressed loss of long-span prestressed concrete continuous rigid frame bridge needs to be strengthened when the loss is close to 20. The prestressing force needed to be applied in the reinforcement is controlled by 20% of the original design value. (2) as far as the overall bearing capacity of the bridge is concerned, After the middle span cracking and the whole bridge cracking, the bearing capacity of the bridge is reduced by 12% and 15% respectively. (3) the effect of the whole bridge cracking and the only middle span cracking on the bearing capacity of the bridge is similar. That is, for long span prestressed concrete continuous rigid frame bridge, as long as one span damage, the bridge has been basically destroyed.
【學(xué)位授予單位】：長安大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：U448.23;U441

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本文編號：2399864