噴射高性能水泥復(fù)合混凝土加固石拱橋承載力試驗(yàn)研究
發(fā)布時(shí)間：2018-08-03 22:00
【摘要】：石拱橋在我國歷史悠久，有著造型優(yōu)美、造價(jià)低廉、取材方便、技術(shù)嫻熟等優(yōu)點(diǎn)。建國初期石拱橋曾得到廣泛應(yīng)用，在我國交通建設(shè)和發(fā)展歷史上發(fā)揮著極其重要的作用。然而由于年久失修、交通量加重、自然災(zāi)害等原因，大部分石拱橋目前存在一定的開裂、破損等安全隱患。考慮到舊危橋數(shù)量多，覆蓋面廣，拆除重建不僅耗資巨大，新建期間社會(huì)付出的“綜合代價(jià)”更為高昂，因此對(duì)舊危橋進(jìn)行加固重利用是最佳選擇。 高性能水泥復(fù)合混凝土加固技術(shù)是一種新型的加固方法，能有效提高構(gòu)件的抗壓、抗彎承載力及整體性能，有效控制結(jié)構(gòu)裂縫開展，，正被廣泛應(yīng)用于砌體和混凝土加固領(lǐng)域。高性能水泥復(fù)合混凝土加固技術(shù)較其他橋梁加固技術(shù)相比，具有施工方便快捷，經(jīng)濟(jì)效益好，無機(jī)材料加固耐久性好等優(yōu)點(diǎn)。用高性能水泥復(fù)合混凝土加固石拱橋，能免去上部填土開挖，大大減少工程量，具有重要的社會(huì)和工程意義。 為了研究噴射高性能水泥復(fù)合混凝土加固石拱橋的加固效果，在湖南大學(xué)結(jié)構(gòu)實(shí)驗(yàn)室中砌筑兩相同模型拱橋，一座不加固，一座考慮到石拱橋通常具有較大的恒載不能卸除，在加載到破壞荷載的70%時(shí)持載做帶載加固試驗(yàn)。通過試驗(yàn)結(jié)果的對(duì)比分析，研究噴射高性能水泥復(fù)合混凝土加固后對(duì)石拱橋開裂模式、破壞形態(tài)及極限承載力的影響。 實(shí)驗(yàn)結(jié)果表明：未加固拱橋模型極限承載力為800kN,在達(dá)到破壞荷載70%時(shí)持載噴射60mm厚高性能水泥復(fù)合混凝土加固的拱橋模型極限承載力為1000kN,承載力提升幅度為25%，噴射高性能水泥復(fù)合混凝土能有效提高拱橋的承載力。 未加固拱橋模型在加載至破壞荷載95%時(shí)，在破壞位置拱側(cè)面迅速出現(xiàn)一條沿拱軸線方向的貫通裂縫，在裂縫出現(xiàn)后很短時(shí)間內(nèi)破壞，基本沒有反應(yīng)時(shí)間，破壞呈明顯脆性。加固后拱橋模型在加載至極限承載力90%時(shí)，在破壞位置拱側(cè)面已有明顯沿拱軸線方向的裂縫，有一定的破壞征兆，說明噴射高性能水泥復(fù)合混凝土能有效改善拱橋模型的脆性破壞特性。加載過程中加固層與拱橋模型粘結(jié)良好，無剝離及滑移現(xiàn)象。破壞后拱橋模型仍保持相當(dāng)?shù)恼w性，說明加固層能有效的加強(qiáng)拱橋模型的整體性。 最后，本文結(jié)合試驗(yàn)和理論分析，提出了對(duì)加固后拱橋模型承載力計(jì)算方法。計(jì)算結(jié)果與試驗(yàn)結(jié)果吻合良好，可供加固設(shè)計(jì)時(shí)參考使用。
[Abstract]:Stone arch bridge has a long history in our country. It has the advantages of beautiful shape, low cost, convenient material selection and skillful technology. Stone arch bridge was widely used in the early years of the founding of the people's Republic of China and played an extremely important role in the history of traffic construction and development in China. However, due to years of disrepair, increased traffic volume, natural disasters and other reasons, most of the existing stone arch bridges have some safety risks such as cracking and breakage. Considering the large number and wide coverage of old dangerous bridges, demolition and reconstruction not only cost a lot, but also the "comprehensive cost" paid by the society during the new construction period, so strengthening and reusing the old dangerous bridges is the best choice. High performance cement composite concrete (HPC) is a new reinforcement method, which can effectively improve the compressive capacity, flexural bearing capacity and integral performance of the members, and effectively control the crack development of the structure. It is widely used in masonry and concrete reinforcement fields. Compared with other bridge strengthening technology, high performance cement composite concrete reinforcement technology has the advantages of convenient construction, good economic benefit and good durability of inorganic materials. It is of great social and engineering significance to reinforce the stone arch bridge with high performance cement composite concrete, which can avoid the excavation of the upper fill and greatly reduce the amount of construction work. In order to study the strengthening effect of stone arch bridge strengthened by shotcrete high performance cement composite concrete, two same model arch bridges are built in the laboratory of Hunan University structure, one arch bridge is not strengthened, the other is that stone arch bridge usually has large dead load that can not be removed. When loading to 70% of the failure load, the loading is carried out with load reinforcement test. Through the comparison and analysis of the test results, the effects of shotcrete reinforced high performance cement composite concrete on the cracking mode, failure form and ultimate bearing capacity of the stone arch bridge are studied. The experimental results show that the ultimate bearing capacity of unreinforced arch bridge model is 800kN, and the ultimate bearing capacity of unreinforced arch bridge model is 1000kNwhen the failure load is 70kN. The ultimate bearing capacity of arch bridge model strengthened with 60mm thick and high performance cement composite concrete is 1000kN. High performance cement composite concrete can effectively improve the bearing capacity of arch bridge. When the model of unreinforced arch bridge is loaded to failure load 95, a through crack along the axis of arch appears rapidly in the failure position of the arch, and it is destroyed in a short time after the crack appears, and basically has no reaction time, and the damage is obviously brittle. When the model of the strengthened arch bridge is loaded to the ultimate bearing capacity 90, there are obvious cracks along the axis of the arch in the failure position of the arch side, and there are certain signs of failure. The results show that shotcreting high performance cement composite concrete can effectively improve the brittle failure characteristics of arch bridge model. During the loading process, the strengthened layer bonded well with the arch bridge model, and there was no peeling and slip phenomenon. After failure, the arch bridge model still maintains a considerable integrity, indicating that the strengthened layer can effectively strengthen the integrity of the arch bridge model. Finally, combined with experimental and theoretical analysis, this paper puts forward a method for calculating the bearing capacity of reinforced arch bridge model. The calculated results are in good agreement with the experimental results and can be used for reference in reinforcement design.
【學(xué)位授予單位】：湖南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：U445.72;U446
本文編號(hào)：2163121
[Abstract]:Stone arch bridge has a long history in our country. It has the advantages of beautiful shape, low cost, convenient material selection and skillful technology. Stone arch bridge was widely used in the early years of the founding of the people's Republic of China and played an extremely important role in the history of traffic construction and development in China. However, due to years of disrepair, increased traffic volume, natural disasters and other reasons, most of the existing stone arch bridges have some safety risks such as cracking and breakage. Considering the large number and wide coverage of old dangerous bridges, demolition and reconstruction not only cost a lot, but also the "comprehensive cost" paid by the society during the new construction period, so strengthening and reusing the old dangerous bridges is the best choice. High performance cement composite concrete (HPC) is a new reinforcement method, which can effectively improve the compressive capacity, flexural bearing capacity and integral performance of the members, and effectively control the crack development of the structure. It is widely used in masonry and concrete reinforcement fields. Compared with other bridge strengthening technology, high performance cement composite concrete reinforcement technology has the advantages of convenient construction, good economic benefit and good durability of inorganic materials. It is of great social and engineering significance to reinforce the stone arch bridge with high performance cement composite concrete, which can avoid the excavation of the upper fill and greatly reduce the amount of construction work. In order to study the strengthening effect of stone arch bridge strengthened by shotcrete high performance cement composite concrete, two same model arch bridges are built in the laboratory of Hunan University structure, one arch bridge is not strengthened, the other is that stone arch bridge usually has large dead load that can not be removed. When loading to 70% of the failure load, the loading is carried out with load reinforcement test. Through the comparison and analysis of the test results, the effects of shotcrete reinforced high performance cement composite concrete on the cracking mode, failure form and ultimate bearing capacity of the stone arch bridge are studied. The experimental results show that the ultimate bearing capacity of unreinforced arch bridge model is 800kN, and the ultimate bearing capacity of unreinforced arch bridge model is 1000kNwhen the failure load is 70kN. The ultimate bearing capacity of arch bridge model strengthened with 60mm thick and high performance cement composite concrete is 1000kN. High performance cement composite concrete can effectively improve the bearing capacity of arch bridge. When the model of unreinforced arch bridge is loaded to failure load 95, a through crack along the axis of arch appears rapidly in the failure position of the arch, and it is destroyed in a short time after the crack appears, and basically has no reaction time, and the damage is obviously brittle. When the model of the strengthened arch bridge is loaded to the ultimate bearing capacity 90, there are obvious cracks along the axis of the arch in the failure position of the arch side, and there are certain signs of failure. The results show that shotcreting high performance cement composite concrete can effectively improve the brittle failure characteristics of arch bridge model. During the loading process, the strengthened layer bonded well with the arch bridge model, and there was no peeling and slip phenomenon. After failure, the arch bridge model still maintains a considerable integrity, indicating that the strengthened layer can effectively strengthen the integrity of the arch bridge model. Finally, combined with experimental and theoretical analysis, this paper puts forward a method for calculating the bearing capacity of reinforced arch bridge model. The calculated results are in good agreement with the experimental results and can be used for reference in reinforcement design.
【學(xué)位授予單位】：湖南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：U445.72;U446
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